| Author | Message | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 22 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
Hi everyone. A couple of newbe questions. 59 PD 4104, 6-71. I'm just getting into my air system and have been through the manual several times but still have questions. I can only get 60psi on my dash. Is there a way of knowing if the compressor is putting out proper air, ie isolate it by itself for a test? I'm a bit afraid of disconnecting it to test it for fear of loosing my ability to shut the engine off, and the only test procedure in the book has a full-up test bench. I fired up the engine and put a tire guage on the fitting near the "T" where it goes back into the compressor gov and it got to 60 psi in about 1 min, then slowly started to show on the dash. It took about 20 mins to get to 35 psi, then I shut it down as I know these engines don't like to idle - by the way I was fast idling - 1000rpm with frequent revving - is that OK?? Maybe just takes longer? The bus has only been driven twice in the past month, then 3 years before that. I read if they sit, it can take a long time to air up? Also, how do I know if the compressor is pumping or bypassing? Does it make a sound that is noticibly different? This is a whole new world! Thanks in advance. | ||
| Bill Gerrie (Bill_gerrie)
Registered Member Username: Bill_gerrie Post Number: 255 Registered: 3-2006 Posted From: 216.198.139.38 Rating: N/A |
Jim There is a govenor (round thing about 1 1/2"x 4") on the side of the compressor that controls the cut in and cut out pressure of the compressor. Could be that it is not working properly. They are cheap to buy or if you are mechanicly inclined you can take it apart. There isn't much inside it. Take the cap off the end, loosen the lock nut and try to adjust first. Bill | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 881 Registered: 11-2005 Posted From: 208.54.200.17  Rating: N/A |
Jim, It takes a long time to air up the suspension, maybe 20 - 30 min if it is sitting a long time, so give it more time. It is much slower to air up at normal slow idle which you shouldn't be using anyway. The pressure is low because the suspension is taking so much. My 4104 does the same thing. Air doesn't start to go into the suspension until it reaches 65psi. You have two large tanks, one aft and one forward, and one small one under the driver. It takes a long time to fill all those tanks plus the suspension. You can fast idle it as long as you like. The book says 1/3 throttle but I don't idle mine quite that fast. 1000rpm is probably good. I never checked mine, I go by sound. If your hand throttle doesn't work (They tend to rust and stick) block the foot pedal to make it run medium fast. It won't hurt it a bit and after sitting so long it will enjoy it!! | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 811 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
Jim, 1. Something is wrong. 2. The compressor governor should cut out (unload the compressor) at about 120 psi, and cut in (load the comp) at about 105 psi. 3. It won't hurt the engine to idle for half an hour, eventually the exhaust will get "wet" with unburned fuel, and because the engine doesn't get warm, it doesn't dry out. 4. Either the compressor is badly worn, which is a possibility, or the air system is leaking. 5. TAKE DAVE'S ADVICE ON AIR RIDE IMMEDIATELY ABOVE, DON'T GO UNDER AN AIRED UP AIR RIDE BUS WITHOUT BLOCKING IT UP AT THE JACKING POINTS! 6. Fast idle is air operated, so you are getting some air pressure at the engine. 7. You should have a low air alarm on... 8. Many buses have a protection valve which doesn't allow air into the auxiliaries until the pressure reaches about 75 psi, I'm not sure about yours. My suggestion for a quick find is to get up what air you can with fast idle, (they do equip buses with fast idle, so it can't hurt) then shut it off and see how long it takes to go down. If the air goes down in a couple of minutes, you have a big leak, which can be easily found with a spray bottle of really soapy water. Spray everything, air bags, valves, lines and fittings, etc. Window cleaner doesn't make as good bubbles. The engine is shut off with air, so find the stop cylinder on the governor, and push the lever, to be familiar with its operation, so you can stop the engine from the rear with no air. You should also be familiar with the emergency shutdown so you know how to reset it if it is tripped. It is on the side of the air intake, and is a small tab, held in position by a latch tripped by a solenoid. HTH, George | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1433 Registered: 10-2003 Posted From: 71.58.110.9  Rating: N/A |
Another thing you should do is: on the air tank in the compartment below the driver's seat, remove the fitting on the bottom after you have exhausted all the air from the coach system. If it has a drain fitting now, you need to tee it there so you can install an air fitting. If you use a male end, you'll need a shutoff valve between it and the tank, so the air doesn't leak out when disconnecting a hose from an air compressor. If you use a female end, you can omit the shutoff as the female has a check valve in it. If you go this way, you'll need to make up a male to male adapter to air up. Why do I mention this? It is a great way to supply air while finding leaks and problems in your system, especially if you get a 100ft hose and get compressor away from coach so noise doesn't drown out the sound of leaks. Another benefit is to save idling time and fuel airing up system. With this and a block heater, once you get everything working right, you can fire up and pull out in less than a minute. Don't forget to unhook the airline and power cord before you pull out.  | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 882 Registered: 11-2005 Posted From: 208.54.200.90 Rating: N/A |
A completely empty 4104 is very slow to air up as I said in my first post. The 4104 does not have an air fast idle system, all it has is a cable hand throttle. Most 4104 low air lights seem to be inop, mine included. It is part of the very complex Alarm system and seems to suffer from owner modification over the years! Original cut in/out for a 4104 is 80/102 psi with the original governors. The original gov was mounted on the firewall just fwd of the compressor. There are two original type gov (No longer available as far as I can tell). I have the regular truck type gov on mine but it won't adjust to the original so I have it at 96/105 psi. It doesn't look anything like the original ones but the fittings are the same so it wasn't hard to convert. There is no way to know for sure your air is going down because you aren't giving it enough time to fill all three tanks and the suspension. If it goes down in two min after that then you have a big leak. John's idea about the air fitting at the aux tank is excellent and the system I use. I have a normal female quick connect fitting for using bus air and back to back male quick connect fittings for airing up with shop air. This won't work at the rear on the muffler drain fitting because of the check valve. I also have a valve before the female fitting so that I can still drain the tank by inserting the double male fitting without blowing the fitting across the parking lot!! | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1534 Registered: 12-2000 Posted From: 98.192.173.82  Rating: N/A |
Jim - Here's a photo of the quick disconnect air fitting in the front compartment of my 4106, under the driver. Your 4104 is exactly the same. As John suggested, hook up a remote air supply to this and let it fill the entire system - save the diesel!  Note that there are two valves on this. Bottom one must be closed to add air, upper one must be open. Open both to drain tank to remove any condensation. FWIW & HTH. . . | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 23 Registered: 1-2009 Posted From: 76.14.148.75 Rating: N/A |
Thanks guys! Here is what I have done. I do have a fitting on my Aux tank and did air it up with my compressor, with some odd results. My compressor is about 2 HP/13 gal/115psi - small but adequate. After about 20 mins, got the suystem up to 65 psi, bags inflated and bus up, but even after an hour with the compressor it would not get over 85 PSI. Unhooked the compressor and it went to 115 and shut off quickly so it is capable. With the compressor off, I found my WW wiper had a good leak, fixed that, and could not hear any other leaks, although I did not get under the bus as I have not set up blocks yet. I found the rear tank, opened the drain and got a little uguly air/oil but not much flow. I stuck a wire in the drain hole to dislodge whatever was pluggin it, and got about a quart of the most discusting 85 psi oil spray ever! Everywhere - live and learn. Apparently the engine has been worked on quiet a bit and the muffler and compressor out were beautifull and clean, but this tank had not been drained in YEARS! So much for the PO's start up routine. By the way, the front Aux tank was clean with just a little water mist, no oil. Have not found the front "dry" tank yet. Pumped it for another hour, still would not get over 85 psi so I am guessing I have a leak bigger than my 3 scfm my compressor puts out. I disconnected the compressor, and interestingly the bags held air, but the system bled down in about 1/2 hour. I think that says my valves for the bags work and are not letting my air bleed back, and the bags are working and holding air. Also interesting is the whole system bled down, not just the Aux. I was under the impression that it should let the aux system go down, but the main "brake" system should not go below 65 psi - right? Does this mean my big leak is in the "brake" part of the system, and not the "aux" part? I'm on my boat now and have been since friday so I don't know how long the bags stayed up. I spend thursday cleaning gobs of grease and dirt out of the tool/aux compartment under the drivers seat so I can see what I have. I'm going to jack it up next week and pull the front tires for the first time. Is it better to jack and block both front tires at the same time to keep things "square", or just do one side at a time? I plan to start to pull all of the air regs/filters/valves etc and clean/rebuild them - I want this bus to be roadworthy and safe! And yes, my low-air buzzer does not work either... Thanks everyone - really appreciate the help and advice! This is a lot of work, but I'm lovin' it! Still cannot get over how well this 51 year old bus has held up - a testament to quality and design excellence! Jim | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1437 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
I don't know if your shutters are still on the coach, but they often leak at the small chamber that closes them till the engine get's warm enough. If it is leaking, there is a small shutoff in the engine compartment to temp eliminate that leak. Also, you need to check with a mechanics stethoscope in that compartment below driver at the bottom of the airbrake treadle. There is often a leak there and it is a real PITA to change or rebuild that treadle. Unbelievable how many pipes are back in that area, not counting the mountains of grease lying around from servicing all those fittings under there. You say it only goes to 85 like when engine was running? Maybe the governor is dumping the excess. You need to get the compressor far enough away so the noise doesn't mask the air leak noises. Even if the air bleeds out, the leveling valves have check valves to keep the air in the bags unless leveling is called for. For some items, you'll need some soapy soulution to check, but for now, a mechanic's stethoscope will allow you to find some pretty small leaks and they aren't that expensive and can be handy to have. I don't know whether you have maxi brakes or the old system, but those actuating valves can leak, and also check the air horn actuating valve in that lower compartment. If you have the original ac/ heat system; they can have several leak sources to also check. | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 24 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
Thanks John. I think the shutters you are talking about are in the radiatior to cut air and warm up - if so, I do not have them but I will see if I can find the air line that would have driven them. I was only able to get to 85 with my shop compressor - did not have the engine compressor going. The shop compressor will do 115 whthout leaks, so there is a pretty good one. I got about the same pressure with the engine compressor so it might be good. I just bought a mechanice stethoscope so I will start tomorrow. As a good point, the air bags on the drivers side are still up after 4 days, and the passenger side is about down, although it seems like the front might still be higher. I will start in the compartment below the drivers seat, although I noticed when I turned the shop compressor off, there was a fairly loud hiss that I beleive was the air escaping the aux tank and "feeding" the leak somewhere else. I'll find it! Thanks - I appreciate the guidance. Jim | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 884 Registered: 11-2005 Posted From: 208.54.200.72 Rating: N/A |
This is about normal for a 4104. There are innumerable places for small leaks, a bunch of small leaks = a big leak!! The aux system leaks into the main system before the main leaks down. The bags should stay up much longer, just as yours does. If you lose air in the brake system the aux will automatically leak into the main so you have brakes. As John says, your gov is probably set for a high of 85psi or faulty. Wipers and wiper controls and connections are some of the worst leakers. Your dry tank is just above the front axle. It is very small and pretty high up. Please do not crawl under there until you have blocks on the bumpers at the air bags. I have a spring loaded drain valve on the dry tank with a cable leading through one sleeve and attached to a screw in the wheel well next to the door so I can drain it easily. The rear wet tank should have an automatic drain installed. It is easy to reach to install from just forward and under the radiator. The original drain valve is a beautiful bronze work of art, but a pain to drain without getting most of the goop on yourself. It is huge, about 2" in diameter. | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 226 Registered: 12-2000 Posted From: 24.164.20.23  Rating: N/A |
Chances are very good on a 4104 that the low air buzzer does not work because they did not rewire the alarm rectifiers when they converted to negative ground. | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1572 Registered: 12-2000 Posted From: 76.68.133.185  Rating: |
oil in the tank indicates a failing compressor passing oil to the air system. Either the present one, or the previous one, if it is new. You have leaks. Keep finding them. All of them. Busnuts are notorious for accepting that the bus leaks...the standard, and the goal, is no leaks. All bets are off with EVERY VALVE in a new-to-you coach. You cannot make assumptions of how the system "should" work, or that it is "working" until you have confirmed functionality of all your valving, and that some previous owner has not rigged it up somehow. Unfortunately, the coach manuals do not always do a good job of informing you as to how to do this... Bendix is an excellent resource to spend some evenings doing some reading on air systems. happy coaching! buswarrior | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 90 Registered: 5-2007 Posted From: 70.53.182.252  Rating: N/A |
Just a note here. My 4104 fully aired out doesn't take more than 10 mins (if that) to air up. That being said I have recently discovered that my rear tank is not plumbed in so it takes 10 mins max to air up the 2 front tanks. FWIW I would check the cut in and out of the governor and if that passes then go on to the compressor, after first checking that you air gage is accurate. Does the dash gage match the pressure at the aux tank? RE: shuttin down the bus once you have cracked into the air system/ if you have no air pressure. Learn how to shut it down either at the air valve shut down thing or by removing the valve cover and pushing the rack shut. (Message edited by zubzub on May 04, 2009) | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 28 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
This is great stuff - I really appreciate your help. It was too cold/windy today to work on the air system so I started the project of jacking it up and taking the wheels off. Started at Drivers front, but could not get the lugs loose! I'll get a bigger impact wrench and hoefully that will do the trick. Don't know what I'll find - the joys of an old bus! Jim | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 886 Registered: 11-2005 Posted From: 208.54.200.101 Rating: N/A |
Len, Same here, there are a bunch of those old rectifiers scattered around my 4104 that are not hooked up and I'm not about to mess with them. I'm eventually going to hook up my "Low Air" light directly to the switch under the driver floor. Zub, My rear wet tank was bypassed just like yours, I didn't know it until I tried to drain it and found no pressure!! The bypass was so neat it couldn't be seen. I now have a new tank installed and that makes airing up a much longer event. The up side is that it also takes much longer to lose all the air. The rear wet tank is much larger than either the front dry tank or aux tank. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1440 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Remember that lug nuts on one side are left hand thread. The wheel studs will have an "L" stamped directly on the thread end. | ||
| L James Jones Jr (Jamo)
Registered Member Username: Jamo Post Number: 62 Registered: 11-2007 Posted From: 24.59.114.248  Rating: N/A |
Huh??? John, are you serious?? I have left & right threaded (single) lugs in the center of my MGB wire wheels, but that's for obvious reasons. Never heard of, or a need for, rt & lt threads on lug nuts. You been drinking??? Thinking you're on the MGBNuts board?? | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1046 Registered: 12-2000 Posted From: 71.3.157.139  Rating: N/A |
Almost every bus/truck I have seen with stud piloted wheels (as opposed to Hub piloted) has left hand threads on the left side and right hand threads on the right side. Jack | ||
| L James Jones Jr (Jamo)
Registered Member Username: Jamo Post Number: 63 Registered: 11-2007 Posted From: 24.59.114.248 Rating: N/A |
Wow...that's a new one on me. What is the reason for that?? Makes no sense to me at this point...at least not until someone can explain. Gonna have to check the Corn Rocket now... Jamo | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 29 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
John, Mine are Left with the "L" on the stud. Still have not been able to crack them loose - those buggers are TIGHT! The spec is 350-400 Lbs, but I suspect they have not been off in 10 years and are rusted. Put some WD40 on them last night so I'll give it a try again today. It's been pretty cold so I have been doing inside projects. I was avoiding spending the money to buy a BIG impact wrench, but my back says it might be time. Off to Harbour Freight (again) later today. Interesting note in the book - I never knew it, but with this high tire pressure, they say that the valve stem cap, metal with a seal, is the actual seal to keep tire pressure up, and not the little spring valve in the tire stem. I have cheap plastic ones on some tires and thought they were just to keep the dirt out! Something to check. Jim | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1048 Registered: 12-2000 Posted From: 71.3.157.139 Rating: N/A |
Jim, If the WD-40 does ot work, try PB Blaster, I have had much better results freeing rusted bolts with the Blaster. I think the metal valve cap is a secondary seal, in case the Schrader valve fails. We had them on our airplane.Jack (Message edited by JackConrad on May 06, 2009) | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1577 Registered: 12-2000 Posted From: 76.66.17.98 Rating: N/A |
Fleet men have always considered the cap to be the seal. The valve is considered to be there to help you keep air in the tire while the cap is off. Metal valve caps with the rubber seals in the bottom have not let down nearly as many tires as what bare/plastic capped valves have... Not easy to find at the automotive store, you have to go commercial. happy coaching! buswarrior | ||
| Bruce Henderson (Oonrahnjay)
Registered Member Username: Oonrahnjay Post Number: 404 Registered: 8-2004 Posted From: 76.21.223.150  Rating: N/A |
Jack wrote: "If the WD-40 does ot work, try PB Blaster, I have had much better results freeing rusted bolts with the Blaster." Yes, "WD" means "water displacement" -- it was never designed to be a lubricant (much less a penetrating oil) and, of course, it was redesigned a few years ago to be "more environmentally friendly" which means that now it doesn't work as well as the original formula did. If you want penetrating oil results, use a penetrating oil -- and PB Blaster seems to be a very good one. It melts 30 year old British rust, salt, dirt and diesel soot better than anything I've tried. But don't depend on WD-40 for lubrication. After it's done it's thing (which is basically drawing water out of components), the chemicals in the stuff draw water out of the air and deposit it on the part you were trying to lubricate. It's pretty good at what it does, but it's not a good lasting lubricant or a good penetrating oil. | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 456 Registered: 3-2007 Posted From: 71.55.197.237  Rating: N/A |
I had to take a bar [6-8ft] put on the socket and actually let the coach do the work. Not a good safe way to do it but,that's all I had to bust them loose with. Do not use anti-sieze on them when you get them off either. If all else fails, I hate to use it but, HOT WRENCH time is here!! Heat the nut up take it off and throw it away and get new to replace them. Do not reuse heated lug nuts, they will not work!! Gomer | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1443 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Take a 3/4 or 1 inch drive breaker bar or ratchet if you don't have the bar. Install the appropriate socket on front wheel stud. Add a 6 foot piece of pipe to the breaker bar or ratchet and with the leverage, you should be able to loosen the lug nut if you are turning in the correct direction. I doubt that rust is the problem, although PB Blaster wouldn't hurt. Those wheel studs are grade 8 and usually don't rust. If the 6 foot pipe doesn't work, use an 8 footer. Make sure the pipe is large enough in diameter that it isn't going to bow and bend. If the ratchet or breaker bar breaks, go to Sears and get one that is guaranteed. If you have air supply, go to a Harbor Freight and buy one of their 1" drive air wrenches when they are on sale, which is usually pretty often. You could get 3/4 or 1 inch stuff there too. They will replace stuff you break. You don't need to mention the pipe. Be careful not to mix left and right lug nuts.You need to use an extension to reach the rear lug nuts. Support the end of ratchet on something so you don't get it off perpendicular and round off lug nuts or break socket. BTW, wear safety glasses in case you split a socket, which can happen if those nuts have been on for a long while. Wire brush and spray the threads showing before you start. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 890 Registered: 11-2005 Posted From: 208.54.200.93 Rating: N/A |
Jim, Gomer and John use the same system I use. Many guys think that using 400 p-f on means it only takes 400 to remove, but it takes far more than that!! One other method for seized large nuts is a nice big nutcracker. It will take a big one but they always work for me. The usual problem is access to the nuts but at least front lug nuts are easy to reach. Jamo, Many vehicles have used L-R lug nuts for many, many years and, as far as I know, big trucks still do. I haven't driven or noticed the newer trucks. Autos stopped using them in the '70s or '80s as far as I can remember. All my older vehicles have them. (Message edited by gusc on May 07, 2009) | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 32 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
Great Ideas. I had a 4 foot cheater on the original bus lug wrench and could not budge it. I was afraid of rounding the nut so I quit. Went to good old Harbor Freight today and bought a 600 Lb impact wrench and matching impact sockets. The whench was on sale for $79 - gotta love H-F! I didn't realize WD was not a true penetrating oil, but I do have some of the PB Blaster so I will give it a try in the morning. This big stuff is all new to me - I build microchips the size of a pin-head for a living, or did until I retired, so a 6 or 8 ft breaker bar is intense! I'm lovin' it, and appreciate the advice - thanks again! Jim | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 893 Registered: 11-2005 Posted From: 208.54.200.26 Rating: N/A |
Jim, Pay close attention to these words by John, "Support the end of ratchet on something so you don't get it off perpendicular". I use a "four-way" truck lug wrench because it is really tough and very easy to support on the opposite end from the lug nut. I usually use a step ladder but anything that can be adjusted for height will work. | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 37 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
Hi All - I bought the impact whench and with a little PB Blaster, it did the trick. It was still a bit of time, but eventually got them all loose with no damage, retightened one at a time, and now I'm ready to jack her up. I have a really cool 25 ton air over oil truck jack, like they use in a commercial shop, but couldnt get it under the axle! If it ain't one thing, it's another! I'm going to drive the tire onto a few 2x12's to get a few more inches, then I'll be ready. It's not like changing a tire on a car! I am deathly scared to get under this beast ( I mean girl) and being super carefull. My front air bags are still full, so thats good news, although the system has bled to zero. I am thinking I should perssure up the system with my partable air compressor, lift the axle, then block the axle. Question - can I block the body now with the bags full, or should I let it come down before I block it? I would prefer to do it up so I have more room under there - I am going to start to remove and rebuild/replace any of the valves, regs, air lines, brakes, etc when I'm there. FYI, I am using clean RR ties for my blocking. Thank you all again! Jim | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 457 Registered: 3-2007 Posted From: 71.55.197.237 Rating: N/A |
River Rat; BLOCK BLOCK BLOCK when the air is up and then when it goes down, it will sit firmly on the blocks. Please be careful and you can't block the beast{HER] enough to be safe. Running it on boards to get it higher in the air will be no problem,just make sure you are BLOCKED SOLID. This board does not support accidental deaths or injuries caused by coaches dropping on there owners. You won't recover overnight and then you won't be able to finish what you started and that is the sad part. If in doubt about blocking, do it anyway,anywhere. On the 04 there are several places that will be sufficient to hold er up. Bulk head at the front of the axles,both sides, the cradle for the engine and tranny also. KEEP COOL when doing this. Gomer | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1458 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
I have to use one of those low profile hydraulic jacks on the 04. I also have jacking plates attached to the bottom of the beam. The one problem with a low profile jack is that it,s travel is limited. I just use it out on the road. At home I now have a pit. | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 39 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
Gomer - BLOCK, BLOCK, BLOCK - you guys have really made that message sink in - I'll be carefull, don't worry. On the board and death - it should be a Board RULE that if a member is killed by not blocking, he should be banned from the board, for at least 6 months, no exceptions! (kidding, of course). John, I am probably going to do a pit down the road, although I just found out a neighbor has one and it might work. Right now I am interested in pulling the drums/hubs to inspect wheel bearings, shoes, etc as well as all the air stuff so jacking is the way right now. I obviously need to know how to do it so I can take care of road emergencies. I think the big shop jack is only off by about an inch, so driving onto a couple of 2x10's will get me there. I bought a nice little 2HP portable compressor for the bus, and I have both 8 and 12 ton bottle jacks in the bus. I also have 2 of the heavy 6-10 ton jack stands, and enough blocks to have, say, a 4-5 hour bonfire! Best to be prepared and practiced if the need arises. Just saw the post on shocks, so will do them now too. I am so loving this bus thing! I feel a little guilty only going to my boat every-other week now, but I don't think she is too upset! Holy smokes, is this palligamy - 2 girls?? Lots of hard work, but my (new) girl is slowly taking shape. You guys are all right! Thank you again! Jim | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1463 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
If any of those airbags have cracks in them, be careful around them and wear ,at least earplugs and eye/ face protection. You wouldn't one to blow out while under there. If you find any in this condition, now is the time to replace them, including installing the air beam block off plates if it doesn't already have them, because, sooner or later, those beams will start leaking. | ||
| David Lower (Dave_l)
Registered Member Username: Dave_l Post Number: 146 Registered: 11-2007 Posted From: 67.58.201.132  Rating: N/A |
Jim I know you are kidding about the death thing but try not to make light of the danger as some of us such as my self have worked with guys that have been crushed by colapsing vehicles it aint a pretty sight! Just do as Gomer says and keep cool when under there and be safe.:-) Dave L | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 896 Registered: 11-2005 Posted From: 208.54.200.33 Rating: N/A |
Again, you must block between the suspension and the body right next to the airbag. I don't trust the bulkhead locations if I'm under the bus. I only use them if I'm not going under. If they were new they would no doubt be ok but there is no way no know how much corrosion is there now after all these years. | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 41 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
Sorry about the joke -bad tast, I apologize - this is dangerous stuff and I will be more carefull.. Gus - Good point on blocking between the suspension and body - thank you. I got the thing up, blocked with 2 hydraulic, 2 heavy stands, and much wood. I pulled the tire, looked around a bit, and then put the wheel back on for the night - just in case! I'm letting it sit on my blocks for a couple days to be sure (got to go to a boat meeting for a couple days) so I want to be sure all is safe. Everything looked better than I expected. Bags had no cracks and were in good shape, at least visually. It still has the air beams working, I beleive, as I seem to remember that the block-off plates require an outside air line. The beams have little rust, at least on the outside, and hold air pretty well. The rubber lines to the brake actuators are not bad, but I am going to replace them to be safe. The shocks are shot I am sure - look really old. I saw the front air tank, but have not started to really crawl around and clean stuff. When I get back, if everything is still stable and as I left it, I will block more and especially between the suspension and body. Then I will dig in with my whire wheel and clean up a few years of dirt and grime. Noticed a fair bit of oil on all the PS gear, but really can't tell too much. I think I will wait till I have a pit to dig into it - it works. My brake shoes lookes good, although I have not pulled the drums. Just doing a wiggle test like on a car wheel, there was no apparent play in the bearings - not sure if you could feel it in such a big system. Damn this stuff is BIG!! I am thinking I should pull the brake actuator and look inside to see what the bellows look like. Is this a good idea, or will I do more damage than good? Do you guys usually change bellows or replace actuators? It's funny as you start to ge into these machines how well built they are. Every thing is very slow and carefull, but I am sure as time goes on, it becomes less intimidating and you you start to learn your way around. Can't imagine doing this without you folks helping and coaching! Thanks again - be back in a couple days. Hey, a general question on air brakes. The rear brakes can be applied with the air switch on the dash. It takes air to apply them. If the air in the system bleeds down, do they stay on, and if so, how? Jim | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1283 Registered: 5-2001 Posted From: 65.74.69.200 Rating: N/A |
DD3 and spring brakes stay on; the ICC lever will allow release. The ICC lever will only be present if you have neither DD3 or spring brakes. Count your rear pot lines; one will bleed off while pots with two or three will not. Be careful and study your service manual. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1055 Registered: 12-2000 Posted From: 71.3.157.139 Rating: N/A |
"Hey, a general question on air brakes. The rear brakes can be applied with the air switch on the dash. It takes air to apply them. If the air in the system bleeds down, do they stay on, and if so, how? Jim" If it takes air to apply them and they stay on when air bleeds off, they are DD3 brakes (there will be 3 hoses on each can) One hose is the service brake, one is to the diaphragm that sets the brakes and the 3rd is to the collar that releases the rollers that were locked against the shaft when you set the brakes (when you make a firm service brake application after pushing in the parking brake knob). Jack (Message edited by JackConrad on May 11, 2009) | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 45 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
I'm back! Got back in there and did some clean up. Aired it up with my portable compressor but it would not get above 80 psi, going in below the aux tank. Soaped everything and saw no leaks, but did notice the leveling valve was leaking out the (I think)exhaust port, based on the drawings. It's between the 2 exit lines to the air boxes. The bus airs up and bags seem to hold fine. I think the bags are full - but remember the body is blocked up. It is possible that it is blocked at max and the valve is wanting to lower it, but I don't think so. It seems to me the leak is from the supply air side, and the bags are staying full. I say this because when the compressor is running,the valve is leaking the whole time. When I turn the compressor off, it continues to leak until the system is bled down, but I think the bags are still full. Seems to me if the valve were wanting to lower the bus, it would just drain the bags, and not the air system, right? I am thinking I can do one of two things to check it. One is to remove and cap the air inlet into the valve and pump up the system. If it gets to 100 psi, thats my big leak. If not, there is another. Second thing would be to remove the control linkage arm and see if moving it elimanated the air leak. It looks like pulling the valve is a pretty good project, especially getting it back in with all those close-fit flare fittings. Any advice or thoughts? Also, the main system seems to be holding air when the aux bleeds down - checked it with a tire guage at the rear. Thats good! Thanks again Jim | ||
| Ralph Peters (Ralph7)
Registered Member Username: Ralph7 Post Number: 12 Registered: 3-2004 Posted From: 66.59.120.99 Rating: N/A |
Most likely leveling valve, or valves but the air boxes for the air bags may have small holes. I would disconnect level valve arms from easyest point first, the valves may leak no matter what. They move and wear. The rear bags on my mc-8 leaks down rapidly (1 hour) but the front stays up for 4 hours or more. BUT I can not hear it leaking. All my air bags have blocking plates. Check all drain valves on all tanks. | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 93 Registered: 5-2007 Posted From: 76.69.254.204 Rating: N/A |
if your main tank in the rear is leaking it may be hard to hear it. It is stuck up in front of the left rear wheel. Sure sounds like you have a big leak in the aux sysytem unless of course as mentioned before your air gagge on the dash is out of wack have you cross checked the pressure with a decent air pressure gage? K>I>S>S> | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 46 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
Thanks! I darined all of my tanks - the rear "wet" had a bunch of oil, but the front "dry" and Aux were clean with just a water vapor. I have cross-checked the air guage and its pretty close, withing 5 lbs of an external gauge so it is a big leak. I will try disconnection the leveling valve today and see what I come up with. Slowly gettin' there, and learning a lot in the process! Thanks again, Jim | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 47 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
My front height control valve has a problem. I pulled it and cleaned it off and started taking the minor parts of it apart looking for leaks, dirt, etc. Turns out the front (fill)control valve assembly was not seated and air was leaking around the valve assembly to the bags, but they were full, so the exhaust valve was just dumping the air! Good size leak. I capped the line after I pulled the valve assy, hooked up my portable compressor, and it pumped right up to 80PSI Vs the 50 with that valve in place. I then discovered the pressure regulating valve under the driver seat compartment leaking like crazy! Don't recall it leaking before, might be because I am pumping in through the Aux tank, or maybe it's just bad. I'll try getting to it through what looks like a floor hatch and see what I can find. On the Height control valve, it takes a special set of wrenches to hold and tighten the control valve assembly called a J-6049-7, a -2, and a -8 Anyone know a trick to doing it, or where to get one of the tools? Thanks again, Jim | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 907 Registered: 11-2005 Posted From: 208.54.200.113 Rating: N/A |
Jim, I don't think there is a floor hatch, sure wish there were! The regulating valve under the driver keeps air out of the aux tank until the press is up to 65 to guard the brakes. There is also a valve there that dumps air back into the brake tanks if they go below 65. It may be the same valve, I don't remember offhand. Airing up through the aux tank won't make anything leak. There are a few check valves there also, it is quite a mess of valves and lines in a very confined space. The clutch/shift linkages are thrown in for good measure! I've spent many hours in that "black hole"! Was 80psi as far as it would go? Should go right on up to 100+. I have a feeling that your leveling valve was dumping air because your suspension was too high, this is normal for that valve. Be sure to apply air to it and see if it dumps air even when you move it up and down. The manual covers this test very well. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 718 Registered: 7-2006 Posted From: 75.209.148.250 Rating: N/A |
I replaced the entire front leveling valve system and it was not much $$ as I recall...did it a several years ago and just paid attention to how the former setup was and had to do a wee bit of "fabrication" for the positioning to be right for the valve to work properly.... no special tools. I agree with Gus...air should go way beyond 100# IMHO Mine goes to 120+- fairly quicklly. Air system thruout is "worked on" constantly...to catch leaks before they get obnoxious and unsafe. RCB (Message edited by chuckllb on May 17, 2009) | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 910 Registered: 11-2005 Posted From: 208.54.200.119 Rating: N/A |
I don't let mine go above about 105 because the original system was designed for 80-100. I'm afraid if I go over that very much I might blow some things. However, it went to 150 a couple of times when the gov failed so I guess it is pretty strong! | ||
| Jim Gibson (River_rat)
Registered Member Username: River_rat Post Number: 49 Registered: 1-2009 Posted From: 75.95.96.192 Rating: N/A |
My front air system is now in great shape. After reading countless posts here about people replacing the leveling valves, I took that route. The leak-prone leveling valves were designed to accomadate 30 people on and off a dozen times a day, and since a "Coach" only varies by about 3-4 people, putting a less "active" system made sense. There are lots of good leveling system designs that allow each bag to be independent, so I will work there as I learn more. I wanted something simple and safe for now, so I removed the valve and installed a dryer and precesion regulator in the bay with all the rest of the plumbing. I put a shutoff valve and additional guage after the regulator, then plumbed back to both front bags. All copper. The air line that originally fed the leveling valve will now feed this system. At 20 psi, the bus starts to lift, 40 psi it is normal height, and 50 about an inch higher. When the bus is running, the system maintains the 40 psi - no more or less. When I park, if I choose, I can close the valve on the exit of the reg so if the main air system drops, the bags will not. If I want to raise or stiffen the ride, I can add air, although I have to stop to do it. Same for lowering/softer ride. It's been 4 days and I have only lost 1-2 psi out of 40 so my bags are tight, and the leaking valve gone! I also have an air guage for this system in the cockpit to see all is OK. It really is simple and effective, but down the road I want to build a fully controlled 4-bag system - in due time. My brakes are adjusted, barly touching the drums, 11/16" shoe, wheel bearings tight and full of clean white grease, and the brake bellows/lines all look good. Got the wheel back on today (first up&down with no mis-hap - a BusNut MILESTONE!) fired up the engine, and got to about 90 psi with the bus and little complessor. Still a major leak in the back, and I suspect the leveling valves. On on front right now, should be a bunch easied this time. BLOCK, BLOCK , BLOCK!! I have a 7.5 Onan, JB series and got it sorted out too. Drained the bus gas tank - really yellow gas but not a lot of particles, then flushed another 5 gallons through the tank. Relpaced the gas lines, bulkhead into the gen bay, added a really big water-separating filter (boat stuff, the size of an oil filter), then added a new electric fuel pump and lines. Pulled and cleaned the carb, new batt and cables, and fired it up. 49 volts, not 120! Working on that one too! Thanks so much for your encouragement! Jim | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 96 Registered: 5-2007 Posted From: 70.53.180.166 Rating: N/A |
Sounds like your getting there.. |
