| Author | Message | ||
| Jim Connelly (Desertbum)
Registered Member Username: Desertbum Post Number: 9 Registered: 2-2005 Posted From: 207.200.116.13 Rating: N/A |
I am trying to tow my 4106 on the hy way to my yard. I filled the air reservoir under the floor of the drivers seat to 100 pounds. It released the breaks but the foot break doesn't work. Only the emergency break works. Every thing else sems ok. I never had a problem with the breaks. The motor quit running yesterday and I am only 3 miles away from my place. I have a friend with a big rig to tow it but not without breaks. Any help is appreciated. Thanks | ||
| Pete/RTS Daytona (Pete_rtsdaytona)
Registered Member Username: Pete_rtsdaytona Post Number: 532 Registered: 1-2005 Posted From: 97.104.13.172 Rating: N/A |
If your Bus is anything like my RTS The e brakes work off the suspension tank -There is a check valve between the the suspension tank and the other tanks (pri / sec brakes , wet tank, etc) - It's there so that a severe failure in the suspension air system will not deplete the air brake tanks so - if you fill only the suspension tank - that's all you get - that check valve prevents the other tanks from being filled. | ||
| Bob MacIsaac (Wildbob24)
Registered Member Username: Wildbob24 Post Number: 26 Registered: 5-2007 Posted From: 74.184.58.175 Rating: N/A |
What Pete says You need to fill the air system from the rear. You should be able to install a fitting at the ping tank to attach your compressor | ||
| David Guglielmetti (Daveg)
Registered Member Username: Daveg Post Number: 5 Registered: 2-2009 Posted From: 69.238.199.247  Rating: N/A |
"ping" tank? What is that...I suppose in Bus Nut slang that is the 'wet' tank, the one that you heard going pingpingpingping while compressor is working? Sorry for the silly question...I'm new here. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 826 Registered: 11-2005 Posted From: 208.54.200.32 Rating: N/A |
Pete, That is correct as far as you went, but there is more. In the original air system if the pressure leaks out of the main tanks the air in the aux tank will flow back to the main tanks. This is to provide for emergency use of brakes. This works because the air suspension, if working properly, will not drain air from the air bags even if the aux tank is empty. In a nutshell, air will flow from the aux to the mains but not from the mains to the aux unless there is adequate pressure in the mains. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 741 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
Pete G, There's no such thing as silly questions. More problems arise when people don't ask questions before doing things. There's no limit on questions here! What Pete RTS meant to say was that BRAKE air is taken off before the auxiliaries. Most of these buses have a protection valve which will not allow air to flow beyond the brake reservoirs until the pressure reaches about 80 pounds. Usually there is a check valve between the wet or ping tank, and the BRAKE reservoir(s). This way, if a pipe or something breaks between the compressor and the brake res, it won't drain the brake res. Also, if something fails in the auxiliary system, the protection valve will close before the leak drains the brake reservoirs. This is why Jim's BRAKES didn't work when he put air in the front of the bus, the protection valve stayed closed because brake reservoir pressure was below 80, and wouldn't allow backwards flow. The solution is to put air in the bus from the back, so the flow is the same as when the engine is running. Connect air to the closest point to the compressor output, and everything will work. Regards, George | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 530 Registered: 7-2006 Posted From: 70.210.237.61 Rating: N/A |
Gus....is that on all airbag systems or 4106 specific? Thanx. RCB | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1517 Registered: 12-2000 Posted From: 67.182.126.60  Rating: N/A |
David - A "ping tank" is another term for the muffler plumbed into the bus air system immediately downstream of the compressor and ahead of the wet tank or wet tank/air dryer assembly. About 6"-8" in length, usually with a drain petcock on the bottom. Here's a pic of the one on my GM 4106, it's the grey cylindrical device to the left of the brass quick-disconnect fitting. This is mounted on the roof of the engine compartment, immediately inside the transmission access door on the curb side.  George - What you and Pete are describing is a dual-air system, something that was unheard of back when the 4106 was in production. Gus's description of the original air system is correct for the 4104s and 4106s. FWIW & HTH. . .  | ||
| Bob MacIsaac (Wildbob24)
Registered Member Username: Wildbob24 Post Number: 27 Registered: 5-2007 Posted From: 74.184.58.175 Rating: N/A |
Dave, The ping tank (also called the "air compressor discharge muffler")is not the wet tank. It is the small tank at the end of the compressor's large discharge hose. It will be mounted high on the bulkhead on the right hand side of the engine compartment. There should be a drain valve in the bottom of it. A 1/4" pipe quick connect airline fitting, to attach your auxiliary compressor, can be installed in this valve. | ||
| Bob MacIsaac (Wildbob24)
Registered Member Username: Wildbob24 Post Number: 28 Registered: 5-2007 Posted From: 74.184.58.175 Rating: N/A |
RJ, You beat me to the punch. We were typing at the same time. | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1504 Registered: 12-2000 Posted From: 76.71.102.226  Rating: N/A |
All bets are off if this is a spring brake conversion. You need someone who knows what they are doing to trace your system and then decide whether is has been safely installed. The aux is not a good place to be plumbing the parking circuit. And I don't mean the average mechanic when I say someone who knows.... happy coaching! buswarrior | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 67 Registered: 5-2007 Posted From: 76.68.231.178  Rating: N/A |
Buswarrior (bus worrier;) ) I had read soemwher that the air supply for the spring brakes could come off the aux tank. The reasoning being that you can watch the air pressure more carefully there, I pressume from your comment above the proper place would be from the main front tank? (that's a little harder to do BTW) | ||
| Jim Connelly (Desertbum)
Registered Member Username: Desertbum Post Number: 10 Registered: 2-2005 Posted From: 207.200.116.13 Rating: N/A |
Thanks for all the feedback. I moved my 4106 off the main road to a safe place to look it over(again). I found a mobile mechanic and he found the problem for the starter not turning over the engine.It was a poor connection on the main positive cable going from the battery to the starter. There is a connection on the bulkhead that was bad. You have to get under the bus to reach it. I'm back on the road again. Thanks again for you comments. Jim | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 827 Registered: 11-2005 Posted From: 208.54.200.69 Rating: N/A |
RJ has completely answered all the other posts. I assumed the 4106 was the same as my 4104 because they are so similar. I also assumed this similarity once before on another part and RJ straightened me out on that one!! I air my 4104 from the front through the Aux tank all the time. It works much better than from the rear. Spring brakes have no effect on any of this. RCB, I don't know about other buses but assume they work the same way. It wouldn't make much sense for the air bags to lose air just because the Aux or Main tanks do. On the 4104 (and probably the 4106) the air suspension controls have check valves to capture the bag air. This is the reason most suspensions stay up much longer than the rest of the air system holds air. The Aux tank may be the best place from which to supply spring brake air because air is needed to release the parking brake and you couldn't release it until full brake air is available. That way the spring brake would apply in case of Aux air loss before you lost normal brake air. But, maybe not! It is a thought. (Message edited by gusc on March 01, 2009) | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 532 Registered: 7-2006 Posted From: 70.212.145.222 Rating: N/A |
Thanx Gus...I think we're on the same "page" RCB | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1267 Registered: 5-2001 Posted From: 65.74.69.188 Rating: |
Gus, if some part of my auxiliary system failed, I would not want to be parked until I got the rig where I wanted it. With the parking brakes connected to the main tank, they would only set when I started losing brake system air supply, and then, I would want them to set. That's why I think that the parking brakes ought to be connected to the main tank. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| Bill Gerrie (Bill_gerrie)
Registered Member Username: Bill_gerrie Post Number: 231 Registered: 3-2006 Posted From: 216.198.139.38 Rating: N/A |
In my bus the parking brakes are connected to the main tank. The release is connected to the emergency air tank so I could remove the bus to a safe location if needed. I have spring brakes. I have since put in a dual circut system but it operates the same way. Bill | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 830 Registered: 11-2005 Posted From: 208.54.200.18 Rating: N/A |
Tom, You're right, it was just a thought going through my overactive mind! After I gave it more thought I realized that even though this would provide a reserve of air in the mains I wouldn't be able to use it to release the springs, so it wouldn't do me much good!! | ||
| David Guglielmetti (Daveg)
Registered Member Username: Daveg Post Number: 7 Registered: 2-2009 Posted From: 69.238.199.247 Rating: N/A |
RJ and Bob, thanks for the muffler lesson. Got lots to learn about buses. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 742 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
Agreed we don't know who did what to whom on the bus in question before the failure to start, but. If the bus was built as described, (aux tank able to charge a lower pressure brake tank,) why didn't the brakes work when the aux tank was charged from the front? Even though the low pressure alarms are on the brake reservoir(s,) I would want spring brakes to apply when brake reservoir pressure was suddenly lost, regardless of auxiliary pressure. Being stopped unexpectedly by a brake application is far better than being stopped by an object belonging to someone else, (that I have to pay to fix, as well as the front of my bus!) Also, why be 'emergency stopped' because of an auxiliary system failure, when the whole brake system is fine? Happy stopping, George | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 831 Registered: 11-2005 Posted From: 208.54.200.130 Rating: N/A |
Can't explain why his main tanks don't charge from the front, but they should? Mine do since they were designed to return aux air to the mains when the pressure drops below 65psi. | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 409 Registered: 3-2007 Posted From: 71.55.228.218  Rating: N/A |
Just a thought??? could it be the line maybe clogged and won't take the air? I had one of them mud dobbers build a nest in an air line fitting and I had to drill it out to get it loose. Just thinking out loud. gomer | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1507 Registered: 12-2000 Posted From: 76.68.133.183 Rating: N/A |
I would wager that many of the more obscure valves are not functioning as intended on many bus conversions. Mechanics don't know how to check them, the maintenance manuals rarely have the procedures for checking them outlined, and busuts have more pressing issues to spend their time fixing. You can't expect ancient valving to work as advertised, if we even know what "as advertised" even means. If you think the reams of educational info on just the simple parts of the brake system are tedious, imagine what it takes to test pressure protection valves, pressure reducing regulators, cracking pressures of relay valves, delay and check features of height control valves, servicing of air suspension filters, the new fangled air operated front door mechanisms.... Should the air go backwards through a pressure protection valve of a certain vintage, even if it does? Then mix in the unconventional ways we try to tap in or otherwise try to make the coach work in ways that were not conventional to their intended purpose.... The wild modifications that some previous owner attempted.... And the advice from those who have decided if it works like that on their bus, it is supposed to work like that.... We must be really careful, this isn't father's Oldsmobile.... happy coaching! buswarrior | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1269 Registered: 5-2001 Posted From: 65.74.69.188 Rating: N/A |
Gus, our 4106 is the same as your 4104 in that the auxiliary tank should pass air into the main tank anytime the auxiliary pressure is higher than the main. It's hard saying what has been modified or has failed, but I think that the check valve ought to be fixed as soon as Jim can get it done. I think that circuit is important for safety and that Jim will want to know what happened. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| Jerry Coombs (Jerry_c)
Registered Member Username: Jerry_c Post Number: 15 Registered: 11-2005 Posted From: 205.188.116.203  Rating: N/A |
my 4106 came with an air pressure regulator between the main air tanks and the aux -- it will not pass air pressure from the main to the aux until the pressure rises to above its setting (about 65psi) As I understood it this was to get pressure in the main system first and quicker. There is a check valve between the aux and main that does allow air to pass between the AUX and MAIN anytime the AUX pressure is higher as mentioned above. I fill my bus from the AUX air tank (its 35' closer to my home air compressor than the rear of the bus -- plus the rear of my bus bumper is about 5-6' off the ground -- engine air fitting would need a laddar or pull the bus off my "railroad tressel" parking spot -- only way I could get a leval parking spot with nothing but hills around). | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 1023 Registered: 11-2005 Posted From: 209.142.172.129  Rating: N/A |
I also charge my system from the aux tank, it is easier to reach and works just fine. I tried it once just down stream from the muffler and it made the check valve at the muffler do a noisy dance, haven't done it since. It appears the 4104 and 4106 have about the same air system, since they are close siblings this makes sense. I like the system because it is pretty simple as built but, as was posted, many things get changed over the years. For example, my ICC valve is hooked up in reverse. Needless to say I have locked it out of the system!! |
