Any reason not to proactively replace brake chambers?

belfert · October 04, 2012, 08:16:41 AM

Twice now I've had bad brake chambers that won't retract fully. Any reason not to just replace the brake chambers that have not yet been replaced? The expensive part is going to be the spring brake chambers as they are type 3636 so they are over $150 each.

eagle19952 · October 04, 2012, 09:10:28 AM

i could be wrong but..
Often the cause of brakes not fully retracting could be broken springs in the drum at the shoes and/or S cam bushings worn or "dead" grease.

belfert · October 04, 2012, 09:20:26 AM

In both cases replacing the chamber fixed the problems. The return springs on the shoes are all relatively new. I have no idea on the S cam bushings. Everything is lubed yearly.

It could certainly be something else besides the chambers causing issues, but the chambers and some of the slack adjusters are about the only things not already replaced. I have automatic slack adjusters and legally I can't replace them with manual adjusters. Several of my slack adjusters have broken in a way that they just keep getting tighter and tighter.

B_K · October 04, 2012, 11:35:44 AM

Brian I just replaced my drive chambers both last summer and if I remember correctly my costs was about $180 for the pair. Now before you get all upset remember if your buying them from C & J or any other garage they will have a mark up on them. (especially if it's a special order item they don't buy in quantity and keep in stock!)

But also keep in mind if the brakes have been HOT then it is best to replace ALL Brake hardware.
It can be bought in a "hardware kit" and includes all rollers, springs and clips to do one axle (some kits might only do one wheel. but your supplier can tell you that)

If you haven't replaced the chambers and have no history as to when they were last changed it would be good insurance to go ahead and replace them due to the age of your bus and the known lack of proper maintenance it had prior to your ownership.
Also MOST (not all) chambers have a grease fitting or 2 it is important to grease these every so often. (most coaches in service get it on a regular PM schedule.) We know as few miles as your coach gets you only have a PM done once a year. Which is fine for oil changes and some items. But it would be in your best interest to get a pair of coveralls a creeper and a good grease gun and slide under you bus and give the brake, u-joint and any steering fittings a shot of fresh grease at least two or three times a year in between the PMs.

BK

belfert · October 04, 2012, 12:25:04 PM

Quote from: B_K on October 04, 2012, 11:35:44 AM
Brian I just replaced my drive chambers both last summer and if I remember correctly my costs was about $180 for the pair. Now before you get all upset remember if your buying them from C & J or any other garage they will have a mark up on them. (especially if it's a special order item they don't buy in quantity and keep in stock!)

I'm just looking online for type 3636 brake chambers and they are all $150 and up each. I need to stop by Fleetpride tomorrow anyhow so I will ask them. I haven't asked any service place how much for the chambers.

Most of my problems seem to have started after my trip to Florida in the winter at the end of 2010. I should have found a place to wash the bus as it was just covered in salt when I got home. The bottom side had twice as much rust as when I started the trip.

buswarrior · October 05, 2012, 06:49:58 AM

I would definitely change out the spring chambers for preventive maintenance purposes.

The return spring in a service brake chamber isn't that strong, you can overcome it with your own hands.

Air integrity for older tired diaphragms, and strength/integrity of the parking springs. Lots of broken springs out there, hiding inside those chambers.

For your sticking brakes, I'd be worried about the state of the camshafts. "dead grease" as mentioned can be a problem here, grease may go in, but not all the way to the ends, as the grooves are plugged with old grease. You want the camshaft to rotate fairly freely but without any sideways movement. There is such a thing as too free!

A full tear down of all mechanical braking components and subsequent replacement of all seals is important to a busnut. You can make a safe bet that the previous commercial owner did it the cheap way by slapping minimum parts on it and not taking things apart for inspection, cleaning and lubrication.

happy coaching!
buswarrior

belfert · October 05, 2012, 08:35:13 AM

I had the brakes completely gone through when I got the bus. All of the of the shoes and drums were replaced along with some slack adjusters. They also replaced all of the wheel bearings. My total bill with a new exhaust pipe and fixing the intercooler was close to $10,000 because some of the parts like the drums were really expensive. I think the parts bill alone was around $6,000.

Wouldn't checking the S-CAMs basically mean pulling all of the drums and removing all of the brake shoes along with possibly removing the slack adjusters? I can see a LOT of $$$ in doing that labor. I have almost zero confidence in doing it myself. The Bendix class I went to didn't talk about actual wheel end stuff.

It sounds like I should plan on replacing the four brake chambers that haven't been replaced already. They really aren't all that expensive to replace.

B_K · October 05, 2012, 10:21:38 AM

Brian I know you had all that done when you bought the bus. But you KNOW at least 2 of the brakes have been overheated AT LEAST once and with that knowledge I'd PROACTIVELY replace all "brake hardware" on the drives and tags if not all the way around.

When the springs get hot they get weak!
WEAK SPRINGS will let brake shoes drag.
Dragging brake shoes cause heat.
Heat causes parts failures.
Part failures cause breakdowns.
Breakdowns cause $ to leave the wallet.

SO as the old saying that I hate when our are field rep from Setra say's (as he holds his hand out) "You can pay me now, or YOU WILL PAY ME LATER!"
But he's right either pony up and fix issues before they become problems or pay a lot more after they do!

BK

belfert · October 05, 2012, 10:50:22 AM

The tag axles have had basically everything except the shoes and drums replaced in the past year. The wheel bearings on the side that locked up was replaced.

I wish I had the knowledge to install the brake chambers myself, but the labor cost isn't too bad for that job.

bobofthenorth · October 05, 2012, 11:35:26 AM

Quote from: belfert on October 05, 2012, 10:50:22 AM
I wish I had the knowledge to install the brake chambers myself, but the labor cost isn't too bad for that job.

Easy for me to say from far away but the thought of the project is way worse than the actual doing. If you can get under there you can do it. Take some pictures before you start. Hold the new part up against the old before you disconnect anything to make sure you got the right part. Then take the old one off and hang the new one. Changing the brake chambers is about the easiest part of any brake service.

Oonrahnjay · October 05, 2012, 12:00:31 PM

Quote from: bobofthenorth on October 05, 2012, 11:35:26 AM
Quote from: belfert on October 05, 2012, 10:50:22 AM
I wish I had the knowledge to install the brake chambers myself, but the labor cost isn't too bad for that job.

Easy for me to say from far away but the thought of the project is way worse than the actual doing. If you can get under there you can do it. Take some pictures before you start. Hold the new part up against the old before you disconnect anything to make sure you got the right part. Then take the old one off and hang the new one. Changing the brake chambers is about the easiest part of any brake service.

I agree. Also, if there are, say, three lines connected to a component, I label them (can be just 1, 2, 3) with white tape and a sharpie, then take the photo. With this, I can be sure that the right line (or other attachable component) gets reattached to the same place on the new component as the old. Also, if I'm not sure, I'll write the number on the old component at the attachment point with the sharpie. There are a number of different ways of getting this done, but slow and careful will work for you.

belfert · October 05, 2012, 12:11:33 PM

My issue with DIY is not changing the brake chamber itself. My issues are not knowing how to make sure the push rod is the right length and how to adjust the brakes properly when done. Obviously, all stroke lengths need to be the same, but my understanding is the angle between the slack adjuster and the chamber is important too. It would be nice to find someone who would train me for some cash.

The simple answer on the push rod is to cut it the same length as the old one. I know enough from reading BW's posts over the years that the last guy may not have cut the push rod to the right length. In my case I highly doubt the chambers have ever been replaced from new, but I don't know for sure.

Oonrahnjay · October 05, 2012, 01:26:59 PM

Quote from: belfert on October 05, 2012, 12:11:33 PMMy issue with DIY is not changing the brake chamber itself. (snip)

Yes, I understand. I think you have a good and balanced attitude between the "do it yourself" and getting pro help. If everyone was all the way to do it yourself, we'd have a lot of mess rolling down the road; if they were all the way to pro, we'd all be broke. It's a balancing act -- and often you're buying experience and knowledge. Going "pro" is often the cheapest way.