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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Michael_e on October 10, 2012, 02:50:08 PM

Title: Scenicrusier Brakes???
Post by: Michael_e on October 10, 2012, 02:50:08 PM
Hi folks, i'm back again and i sure hope it to be more regular with my visits and questions. Life sure has presented some challenges over the last several years, like it has done to so many others. Kyle B. (Kyle4501) provided a good ear to listen to my problems and helped me rethink some decissions. I/we finally got our house in Colo sold and are now in a small town in the middle of Kansas. Anyway, i think the worst of our challenges are now behind us and we are trying to 'gain traction' and move forward.
Our bus is a 1955 GM Scenicrusier. We upgraded to a 8V92TA and 5 speed Allison. We gathered a lot of other various parts for upgrades and interior work before getting layed off. I'm wanting to move the bus around to a different location at my shop. I tried airing up our crusier yesterday and ran into some challenges. First, the bags on the front axle don't seem to be getting any air at all. Second, i don't seem to be getting much more than 60-70 lbs on the pressure gage at the front. Finally, when you press on the brake pedal and release, you get that normal air exhaust sound and the gage shows a loss of pressure and never seems to build back up. I tried tracing the path the air would take in the front left corner compartment under the drivers area and just got lost in all the valves and controls and all the other associated lines and such. I tried to find information in my shop manual but all i found was one grainy picture with no real explanation. Does any 4501 owners out there know how all those things work and have a 'flow' chart or diagram? Sorry, didn't mean to write a book.     Mike

Title: Re: Scenicrusier Brakes???
Post by: ol713 on October 11, 2012, 10:05:44 AM

     I don't have a 4501, but it might be similar to MCI.
     You might have a close look at the governor on your
     air compressor.  If you replace it, they are only about
     $40 --$50 or so.  They are mounted on the air compressor.
     Hope you can find it.


Title: Re: Scenicrusier Brakes???
Post by: belfert on October 11, 2012, 11:05:38 AM
If you can't get the air pressure above 60 to 70 pounds that likely explains your problems with the air suspension.  Many air systems have pressure protection valves that don't allow air to accessories when the main air system has low air pressure.

Title: Re: Scenicrusier Brakes???
Post by: Michael_e on October 11, 2012, 03:03:57 PM
Thanks for the replys so far. I went back and re-read my post and it looks like i had one of those brain pfharts. I forgot to say that i was airing up the bus with my shop air compressor, and, that the rear axles air bags do inflate, just not the front axle air bags. I took pencil and paper and spent about an hour trying to diagram out all the lines, fittings, and valves in that left front compartment under the drivers area. Man-o-man were there a lot of t-fittings, valves, and lines. I did have the throttle converted over to an air throttle, so that just added a little more to the picture. I think i understand about 20% of whats going on there, but still have a long way to go before it's all clear. Maybe i can try and post a pic or two tomorrow. Does anyone know where i could purchase a new front leveling control valve for the front axle/bags?

Title: Re: Scenicrusier Brakes???
Post by: B_K on October 11, 2012, 03:53:39 PM
Just thought I'd chime in an say if your paying $40 for a D2 governor your paying too much! They run about $15-25. (depending on where you buy them and if you get a discount or not)
;D  BK  ;D

Title: Re: Scenicrusier Brakes???
Post by: kyle4501 on October 11, 2012, 06:45:59 PM
Hey Mike!
Luke at US Coach can help you with parts like the leveling valves.

The air system can be a funny thing - leave the shop air connected & see if she wakes up. Some of mine that have sat for a long time, took several hours before the front would air up.

Title: Re: Scenicrusier Brakes???
Post by: Michael_e on October 14, 2012, 03:16:53 PM
I reconnected my shop air compressor, disconnected the front leveling valve arm from the coach and hooked up a temporary wire so i could work it back and forth. Well, after doing that for about 10-15 minutes she started taking air to the bags. As long as our bus has been sitting, i think a good cleaning of the air valves and lines would be a good idea. Any suggestions on how to flush out the air lines? I just don't quite know how i should deal with all the brake 'stuff' in the left forward compartment. Maybe disconnect what looks like the main feed and install a temporary bleed line there. Is there some kind of liquid cleaner i could use as a flush?
Also, i finally called it a day after getting all the air bags working and seeing ole 278 standing proud on her legs. It really felt like i had made some real progress. Next day comes around and what was interesting was that the front air bags were still holding air, but the rear bags were completly down. There must be some leakage on the rear axles. Just something else to chase down. Thanks for listening...

Title: Re: Scenicrusier Brakes???
Post by: belfert on October 14, 2012, 05:10:04 PM
My personal suggestion would be to replace the valves.  Most valves are available as re-manufactured to save money.  There is a good chance the valves have seals and o-rings that are no good by this point, especially if air line antifreeze was ever used.

Unless you need to drive the bus, I would leave fixing the air system closer to the end of the project.  You don't want the new stuff to age prematurely while you finish the rest of your project.

Title: Re: Scenicrusier Brakes???
Post by: sledhead on October 15, 2012, 06:16:04 AM
Mike if you want to remove the air bags from the air system you can put on a 4 point  leveling system with a one way valve. This is what I did for camping . Now at lest the level of the coach is not losing air like the rest of the bus when it is siting.     dave

Title: Re: Scenicrusier Brakes???
Post by: gus on October 15, 2012, 01:07:42 PM
I'm assuming your '55 has the same air system as my '54 4104.

If so; it takes a long time to air up the suspension which, I assume, has air beams. Especially if it has been parked a long time.

Where are you connecting the shop air? It doesn't work well at the muffler just after the comp. It needs to go directly into the wet tank or aux tank. The Aux tank is usually the easiest to access.

As already posted, the Aux tank which goes to the suspension, doesn't fill until the two main tanks have at least 60psi.

You will probably find this has a simple solution if it worked OK before you parked.

Title: Re: Scenicrusier Brakes???
Post by: buswarrior on October 15, 2012, 07:34:10 PM
Also, how big a shop compressor?

The big box retailer size compressors at 120 volts are given a real workout airing up a coach.

If you want to help out your tired air valving, choose an oil spray LUBRICANT of your choice that is NOT laced with solvents.

So, NOT WD40...

These lubes are usually the more expensive cans on the shelf.

Shop air tool oil is also a good choice.

Crack open the air connection upstream, and give it a blast of lubricant, and reassemble.

Build air pressure and cycle the lubricated valving. Expect oily over spray out the exhaust ports of lubricated circuits.

happy coaching!

Title: Re: Scenicrusier Brakes???
Post by: gus on October 16, 2012, 01:41:02 PM
Be sure to let us know the outcome.