| Author | Message | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 5 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
I have a 1960 4104. It has an air valve that is next to the shifter. The air lines go throught the floor and into the compartment below the dirver. There is a small air tank and some kind of air device that kind of looks like a diaphram. I have activated the lever but nothing seems to happen. (well there is a little clicking noise) What is this for????? | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 42 Registered: 12-2000 Posted From: 71.30.252.100 Rating: N/A |
Just a guess, maybe someone added an air assist clutch of some type. Len | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 6 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
It does have air assist clutch. But what does the valve do? Enable/disable the air assist? . | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 43 Registered: 12-2000 Posted From: 71.30.252.100 Rating: N/A |
To the best of my knowledge, air assist was not stock, it's something someone has cobbled up. Some of them might be actual air assist and some are just an arrangement to hold the clutch down while stopped at a light. There's no way to tell from here. It sounds like you might have the latter. Press the clutch in and operate the valve - see if it holds it down. Len | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 7 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
Thanks I'll try that. . | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1035 Registered: 12-2000 Posted From: 67.181.163.170 Rating: N/A |
A picture would be helpful. It could be the OEM ICC valve. Try rolling forward about 5 mph and flip the switch to see what happens. HTH. . . | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 9 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
ICC Valve? OK, if it is this ICC Valve, what should I expect to happen? . | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 45 Registered: 12-2000 Posted From: 71.30.252.100 Rating: N/A |
The ICC valve was before spring brakes. It's function was to divert all the available air to the rear brakes in an emergency. If you operate it, you would definitely hear the rear brakes apply and then a "whoosh" from the valve when you release it. I didn't mention the ICC because you weren't getting those sounds. That said, I think you should get and study the maintenance manual for your bus. You should have a solid understanding of the air brake system with all it's various valves and components. The old GM maintenance manuals are some of the very best ever written, clear, well illustrated, easy to read and understand, and a fantastic education. Len | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 10 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
My mistake not mentioning the sound of released air when the valve is returned to "off" position. So this ICC valve will apply full air preasure to the REAR brakes. (not something I want to test at high speed then) I have ordered the PD4104 Maintenance Manual 55018A and the Engine Series 71 Inline Maintenance and Repair Manual 55055C from Coachinfo .com. A bit pricey but money well spent. | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 46 Registered: 12-2000 Posted From: 71.30.252.100 Rating: N/A |
You are going to want to look into installing spring brakes on your bus. In your case (and mine) if you have a catastrophic failure and lose all air pressure, there will be NO brakes! In a 45-50 year old bus, the chances of a failure are pretty high. The handbrake is all but worthless to try to stop a moving coach. Len | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 11 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
OK, Now I am confused. I thought that Air Brakes worked opposite. Meaning that it took air preasure to release the brakes. I'm sure that is how the brakes work on my bus. . | ||
| Bob greenwood (Bob_greenwood)
Registered Member Username: Bob_greenwood Post Number: 198 Registered: 7-2006 Posted From: 4.227.112.10 Rating: N/A |
remember the 'swooch'...air escapeing | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 12 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
HHHMMMM,,,,, Yes, it does make sense that applying preasure is activating the brakes instead of releasing them. when you think about the air release "swooch". I guess I need to start using the hand brake more often when parking for an extended time. The air leaks down to about 20psi if it sets for about a week. (it has been parked on level ground though) . | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 907 Registered: 12-2000 Posted From: 65.92.188.47 Rating: N/A |
Austin, Is there some educational establishment nearby that offers training to new truck drivers? You might want to take an air brake course, and then when you are done, remembering your bus does not have any of that built in safety. More than likely, the instructor won't have a clue about how your bus works, and may pretend to and give you bad advice. Learn what they teach, and then work from there. Get your manuals, and then do your thought checking on the BNO board. We don't want you to hurt yourself, or heaven forbid, someone else! You need to find out how your particular bus is equipped, what some previous owner may have scewed up or retrofitted, and be absolutely sure that your ideas of how it is working are correct. Driving along, and having no brakes to stop with, never mind if it rolls away when parked, only because you didn't know what you were doing, does not make for a good day! There are quite a few of us on here that can help you. Get a digital camera and get some photos on here. If you don't know how, Ian, the BNO bossnut, will help you, e-mail them to him, and he can resize and add them to your post. And everyone will learn something, not just you! happy coaching! buswarrior | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 13 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
I will dfinetly be looking at the manual when it arrives. I have not yet found anything that I cannot figure out by either taking it apart or by reading up on it. I'm sure this bus will be no different. My GTO was in boxes when I first got it and it only took me about 3 weekends to put it together and get it running. Thanks for everyones help. I will get some photos and post them. | ||
| R.J.(Bob) Evans (Bobofthenorth)
Registered Member Username: Bobofthenorth Post Number: 104 Registered: 10-2004 Posted From: 64.110.227.34 Rating: N/A |
Just make sure you are reading accurate information when it comes to brakes. There is a tremendous amount of MISinformation gets published about air brakes. Armchair experts abound on a system that leaves little margin for error. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 198 Registered: 11-2005 Posted From: 63.97.117.14 Rating: N/A |
The ICC valve works the opposite of spring brakes and is for underway emergency use only. The 4104 manuals say "Do not use for parking" for a good reason, when the air leaks down the brakes release! | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 14 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
Do not use What for parking? the ICC valve? I have a valve on the dash for parking. It releases the air when applying the parking brake. that is why I was thinking the air preasure is dropped to apply the brakes. I also have a hand brake that locks the driveshaft. I will try to get photos tonight. . | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 910 Registered: 12-2000 Posted From: 64.228.90.2 Rating: N/A |
Maybe best to block the wheels on that bus until we get this sorted out.... better safe than sorry!!! happy coaching! buswarrior | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 15 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
OK. Here are a few photos. MY Bus  ICC Valve?  Clutch Air Assist  Parking Brake valve  | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1036 Registered: 12-2000 Posted From: 67.181.163.170 Rating: N/A |
OK, NOW we're getting somewhere!! The "ICC valve?" pic is exactly right - that's the OEM ICC valve, which, as previously described, supplied emergency air to the rear brakes. At least it did when it was new from the factory. The "Parking Brake valve" pic is the more modern and common parking brake valve that the majority of non-early GMC owners recognize. It SHOULD be plumbed in such a way that when you pull it out, it releases the air in the rear brake chambers and sets up the spring brakes. Pushing the valve back in puts air back into the chambers to overcome the spring tension, thereby releasing the brakes. Unless they're DD3s, in which case you have to push in the button, then fully apply the foot brake pedal for 5 seconds or so to release the brakes. Because you've got that button on the dash for the parking brake, it is possible that the ICC valve has been disabled. The only way to know for sure is to trace the plumbing. Same goes for the clutch air assist. The only way to really know how it's controlled is to trace the plumbing. The old "Johnson bar" handbrake is a good supplemental parking brake, but not to helpful in an emergency situation. As for "So this ICC valve will apply full air preasure to the REAR brakes. (not something I want to test at high speed then)", there was a discussion about this just recently both here on BNO as well as over on the MAK BBS. Here are links to the two threads: http://www.busnut.com/bbs/messages/11/14556.html?1155780115 http://www.busconversions.com/bbs/index.php?topic=1489.0 HTH, and thanks for posting the pics! | ||
| Austin Davis (Zimtok)
Registered Member Username: Zimtok Post Number: 17 Registered: 9-2006 Posted From: 63.94.78.194 Rating: N/A |
I have tested the ICC valve at a SLOW ROLL. It does still work. The rear brakes did start to lock up just before I released the valve. I push the parking valve in to release the brake and pull it out to apply it. No need to have the foot brake aplied. I'm fairly sure the Clutch air assist works also. I do hear the air release when the clutch is released. I think the clutch needs a little adjustment though. I have to push the pedal to the floor to fully release the clutch. Inn comparison my GTO has full release with some pedal travel still left. Is the "hand wheel/knob" on the clutch linkage where I would adjust the clutch? . | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1039 Registered: 12-2000 Posted From: 67.181.163.170 Rating: N/A |
Austin - Proper clutch adjustment on your 4104 actually begins up front, and works it's way to the rear. The procedure is outlined in the shop manual, which I understand you've got coming from coachinfo. And yes, the "hand wheel/knob" is part of the adjustment process. When adjusted properly, the 4014's clutch is almost as light as a VWs. . . HTH. . .  | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 47 Registered: 12-2000 Posted From: 71.30.252.100 Rating: N/A |
Austin, Keep the ICC valve. It comes in very handy when you are trying to run the coach up on ramps. It's very difficult to work the clutch, throttle and brakes at the same time. Len | ||
| David Evans (Dmd)
Registered Member Username: Dmd Post Number: 90 Registered: 10-2004 Posted From: 71.125.20.114 Rating: N/A |
Austin, $ well spent is George Myers' Air Brake systems book. You will find the link on the main page here at Bus Nut. Maybe youve read his articles in the BusConversions magazine. This is the whole airchilada. George is good people. |