Parking brake won't release on old bus RV

[wsc9tt]

This isn't a tractor, but it seems like the type of thing people on this forum would enjoy.

I have an old bus made into an RV

It is a 1964 Flxible New Look suburban model with a Detroit 6v71 engine and a 5-speed manual transmission.
It was originally the VIP airport shuttle at the Hanford Nuclear power plant in western Washington.
We have driven across the country multiple times and all around the midwest.

Anyway, I couldn't get the air brakes to release the parking brake before leaving for our most recent trip. Three wheels were fine but one of the rear duals was still locked. This was after sitting for about 10 months. I have never had this problem before. I read online that I need to knock them loose with a sledge, but you really can't get to them. I hired a guy from a local repair place and he thought he was going to fix it with 2ft rod and a hammer and ended up needing an air hammer. Even then he only got the top brake shoe loose. Then we needed to use the engine to break the other shoe loose. The problem is that my bus sits with one pair of tires on gravel.

The locked tire was on the left of the picture on concrete and the pair that would spin was the one on gravel. As you can guess it dug a hole. I needed to jack up the rear and replace the gravel before it finally came out.

Suggestions on how to avoid this in the future? The truck place said I need to move it once a month, even if it is only going 10ft. That isn't really an option in the winter here. I think last year I moved the bus after a week of working on it in the driveway so my theory was that the brakes were cold and it was a damp day. This time I drove the bus enough to get the brakes hot before parking it.

 

[Dftodd]

The biggest issue for air brakes not releasing is the linkages and pivot points rusting and sticking. Making sure all the zirc fittings are greased will sure help.

 

[Jstpssng]

Sorry that I can't help you, but you are right on your first point... this is the type of thing which some of us enjoy.
That bus is just 5 years younger than I am. I'll bet that you've had some fun times based out of it.

 

[jaxs]

I had a 1947 Chevy Fleetmaster Sedan with air brakes when I was a kid. Passengers would ask "air the brakes even working on this thing"? Anyone else ever have to "pump the brakes up" on a car?

 

[ROUSTABOUT]

You can probably get under there and un bolt the bottom half of dust shield behind brake pads and tap the shoe loose. It will move sideways a little. I wouldn't get too happy with a sledge because they can bust. Shoes just rusted to drum and need a little coaxing. Make sure they are off so you can tap loose.

You can put some traction under gravel tires and try that. You can take the wheels off the stuck side if you want. I can only give you three bad options. That is, if it won't break loose externally.

 

[wsc9tt]

The biggest issue for air brakes not releasing is the linkages and pivot points rusting and sticking. Making sure all the zirc fittings are greased will sure help.

Yes, they are all greased and once the shoe was unstuck from the drum the brakes operated smoothly. But yes it is probably time for me to go crawl around under that thing and grease everything again.

Shoes just rusted to drum and need a little coaxing. Make sure they are off so you can tap loose.

I am not sure you are really picturing these things. ;-) The drum is 16.5in diameter and the shoes are 10in wide. The backing is heavy steel and the material is at least 3/4" thick. They were rusted to the drum and "tapping" won't be noticed.

 

[ROUSTABOUT]

If you take the dust cover off you can tap the shoe. Directly on the shoe itself. And if you have them released or backed off at the chamber adjustment, they should come loose with a little tapping. I just got some loose on an old mack we put a log loader on. We had bought the truck a few years ago, but the other one kept going. I have an F850 with air brakes. Un stuck it right rear stuck. Yeah I can picture it. Hitting the s cam don't always do it.

Yes, they are all greased and once the shoe was unstuck from the drum the brakes operated smoothly. But yes it is probably time for me to go crawl around under that thing and grease everything again.


I am not sure you are really picturing these things. ;-) The drum is 16.5in diameter and the shoes are 10in wide. The backing is heavy steel and the material is at least 3/4" thick. They were rusted to the drum and "tapping" won't be noticed.

 

[tacticalturnip]

I can't help you any, but I've got to chime in and let you know your RV is pretty awesome.

 

[bcp]

The truck place said I need to move it once a month, even if it is only going 10ft. That isn't really an option in the winter here.

I would think moving it even a few inches would break loose any rust. Probably could do that even with lots of snow.

Bruce

 

[wsc9tt]

If you take the dust cover off you can tap the shoe. Directly on the shoe itself. And if you have them released or backed off at the chamber adjustment, they should come loose with a little tapping. I just got some loose on an old mack we put a log loader on. We had bought the truck a few years ago, but the other one kept going. I have an F850 with air brakes. Un stuck it right rear stuck. Yeah I can picture it. Hitting the s cam don't always do it.

Yeah sorry.

In this case, these are old Rockwell Coach brakes. There isn't a dust cover and you can directly see the shoes from under the bus. Unfortunately, they are mostly blocked by this train-like frame that holds the rear differential and the 4 air shocks that hold the coach itself.

When I say we pounded on them with a 2ft rod and a sledgehammer that was directly on the shoes themselves and they didn't budge. With everything fully aired up and the brakes disengaged.

It took an air hammer on the side of the shoes directly to get them loose and then only one of them because we couldn't get a clear site of the other shoe.

To address another comment removing the tires is a major undertaking that I don't have to tools to do and doesn't actually provide much more access to the shoes. Just a nicer place to stand while working.

I would think moving it even a few inches would break loose any rust. Probably could do that even with lots of snow.

The issue is not snow, but starting that big cold diesel in the cold. It doesn't have glow plugs and starts by pure compression. I don't have a block heater installed. It originally had a Webasto heater that didn't work, I ended up removing that and selling it on ebay for a couple thousand $$. It also had a 4-cyl Kubota diesel pony engine that ran the old coach AC units that I sold and that covered a good fraction of my original purchase price and gave me space for a storage locker.