Brake issue(s) finally fixed, it's been a journey!

[Nasdaqsam]

I don't get on IRV much anymore. No time and had a few experiences some time ago on here I was not happy with so I left. But I wanted to share my brake dilemma so others with similar issues might have a direction to go.

Since I bought this coach (2nd owner) I have never felt the brakes were quite right. To begin with it had a clunk in the brakes under hard braking. It also had a modest pull to the drivers side when the brakes were applied. And lastly I never felt this coach had the braking power it should have. This is a 26,000lb, 37' rig with the same brakes, chambers and drums as many semi's that stop 100k loads all day long. It didn't add up.

Setting the stage. As this is a 2004 and has always been registered in NY it has gone through 17 state inspections to date. I have also had the brakes specifically looked at 7 times by 7 different shops from NY all the way to Florida. 4 of those times I asked that my specific concerns be addressed and stated I had no issue changing out everything if that corrected the issues. To date no one was able to correct the issues I was describing.

After all this I decided to just have a look myself. To note, I have never worked on air brakes before but have a descent mechanical background. I brought the rig to my friends shop since he has big enough tools to tackle a job like this. He owns an excavation company with full time mechanics. I used one in particular for guidance but I did all the work.

The coach has 80k miles on it. I began with the rear brakes. As expected it had the original pads/drums and about 60% wear. Both sides had even wear so everything looked good on the rears. I replaced the chambers, slack adjusters, pads and drums.

The front brakes. The passengers side looked like they had about 10% wear on the original pads/drum. 10% wear? That's not right. The slack adjuster is working fine. The chamber appeared to be ok the pads move when the brake is applied. We checked the air to the chamber it is fine. So, why only 10% wear? After some further investigating it turns out the chamber was indeed moving the pads but without any real pressure. Faulty chamber. I have to assume this happened very early on in this coaches life since there was so little wear. This also had to be the pulling to the drivers side issue and the lack of braking power issue.

The drivers side pads had been replaced and at some point someone put a used chamber in. It was clear this was a rusted chamber that was painted over. The replacement pads were also the wrong pads. They were slightly smaller than the correct ones. This had to have been causing the clunk. The pads were rotating to the stops under hard braking.

I replaced everything on the fronts as well. Everything is working perfectly now and it has a "significant" increase in braking power, it feels like a different coach all together. No pulling and no clunk.

So the $64k question is how did so many professional mechanics miss this? I do not believe it was incompetence as I have had this rig to some really good shops. My thought is complacency. They looked at the passengers side, saw full pads that moved when the brake was applied, so move on it has to be something else. The drivers side doing all the work was always way out of adjustment so adjust it and be done with it. Even when they replaced them it could have been they felt the passengers side was out of adjustment so put all the pressure on the drivers. As far as the wrong pads that is easily understandable also. It is very difficult to get part numbers for a coach of this age and the original pads were so full of brake dust, grime and rust finding part numbers is impossible. The only way to get new ones is to match them up from the old ones. The wrong ones were very close but not exact.

Whenever I had it looked at I believe they thought they fixed it. Even a quick road test when freshly adjusted under regular braking proved to back up the brakes are ok. But the minute I got on the road under hard braking it acted up again.

Some advise I can give is. If you think something is wrong with your rig even when the professionals are telling you nothing is.....you're probably right keep looking.

[Bobby F]

Originally Posted by Nasdaqsam

So the $64k question is how did so many professional mechanics miss this?

Nobody loves our rigs or vehicles like we do. So, if you can educate yourself about the specific equipment, DIY isn't just cheaper, it's better.

[shootist]

Professionals are only professional because they charge for what they do.
By the time most of us really are good at our trade we're ready to retire. There are exceptions and they are to be admired.

[Nasdaqsam]

Originally Posted by Bobby F

Nobody loves our rigs or vehicles like we do. So, if you can educate yourself about the specific equipment, DIY isn't just cheaper, it's better.

So true. I saved over half doing it myself plus I got educated in the process and now I know how to adjust my own brakes and what to look for if something goes wrong.

[Nasdaqsam]

Originally Posted by shootist

Professionals are only professional because they charge for what they do.
By the time most of us really are good at our trade we're ready to retire. There are exceptions and they are to be admired.

Have to agree with you. I was surprised by one of the guys I brought it to though. He is considered to be a great at diagnosing issues and has impressed me more than once.

[jacwjames]

Good writeup.

Can't complain about my braking at his point but I know it is coming as I have ~110K on my rig. I inspect my brakes at least 2 times a year and all appears good. Just got back from a long trip and the rig performed well. Some bozo pulled in front of me in heavy traffic and I had to do a hard stop almost locking up the tires. New tires and good brakes saved his bacon and mine.

[NXR]

Originally Posted by Nasdaqsam

Have to agree with you. I was surprised by one of the guys I brought it to though. He is considered to be a great at diagnosing issues and has impressed me more than once.

If you have not already done so, please consider contacting him and letting him know what you found. Nothing bothers a true professional more than missing something. If nothing else, you can bet he won't miss that problem for anyone else.

Ray

[outlaw5067]

Originally Posted by NXR

If you have not already done so, please consider contacting him and letting him know what you found. Nothing bothers a true professional more than missing something. If nothing else, you can bet he won't miss that problem for anyone else.

Ray

Agreed. It's aggravating not being able to solve the problem, but to find out what caused it, he'll never miss that again...

[CountryB]

Originally Posted by Nasdaqsam

The front brakes. The passengers side looked like they had about 10% wear on the original pads/drum. 10% wear? That's not right. The slack adjuster is working fine. The chamber appeared to be ok the pads move when the brake is applied. We checked the air to the chamber it is fine. So, why only 10% wear? After some further investigating it turns out the chamber was indeed moving the pads but without any real pressure. Faulty chamber.

The drivers side pads had been replaced and at some point someone put a used chamber in. It was clear this was a rusted chamber that was painted over. The replacement pads were also the wrong pads. They were slightly smaller than the correct ones. This had to have been causing the clunk. The pads were rotating to the stops under hard braking.

Can you clarify? Do you have front "drum" bakes or "disc" brakes?
You use the term "pads" which are associated with disc brakes but also say "drum" (drum brakes have "linings" or "brake shoes").

I'm curious how the air brake chamber failed. If the air diaphragm is not leaking, there is not much else that can go wrong (there's only one moving part). What happened to yours?

Could someone have installed a smaller brake chamber (i.e. they incorrectly installed a smaller Type 16 on the passenger side where the drivers side had a Type 20 chamber)?

https://www.haldex.com/en/na/actuato...9-through-t20/

[Xmcdog]

Originally Posted by CountryB

Can you clarify? Do you have front "drum" bakes or "disc" brakes?
You use the term "pads" which are associated with disc brakes but also say "drum" (drum brakes have "linings" or "brake shoes").

I'm curious how the air brake chamber failed. If the air diaphragm is not leaking, there is not much else that can go wrong (there's only one moving part). What happened to yours?

Could someone have installed a smaller brake chamber (i.e. they incorrectly installed a smaller Type 16 on the passenger side where the drivers side had a Type 20 chamber)?

https://www.haldex.com/en/na/actuato...9-through-t20/

Kinda curious about the pot myself. Was it a partly restricted or crimped hose maybe? Usually a pot works or leaks air.

Any reason you started with the rear axle? Most braking effect is with the fron tires.
Thank you.
Very good write up BTW.

[twinboat]

Originally Posted by Xmcdog

Kinda curious about the pot myself. Was it a partly restricted or crimped hose maybe? Usually a pot works or leaks air.



Any reason you started with the rear axle? Most braking effect is with the fron tires.

Thank you.

Very good write up BTW.

The brakes with the most weight over them do the most work.

On trucks and RVs, that would be the much larger rear brakes.

[dieselclacker]

Originally Posted by twinboat

The brakes with the most weight over them do the most work.

On trucks and RVs, that would be the much larger rear brakes.

The front and rear disk brakes on my Workhorse chassis are all the same size. It has a 14500 lb rear axle, and 7000 lb front. Weight transfer on the chassis with forward momentum motion also has to be considered in brake sizing.

[dfuelman]

Good work and good find. I have done some jacked up things when money was tight, but who in the world installs USED BRAKE PARTS? It's a shame we can't go back in time and find out what they were thinking at the time.

[twinboat]

Originally Posted by dieselclacker

The front and rear disk brakes on my Workhorse chassis are all the same size. It has a 14500 lb rear axle, and 7000 lb front. Weight transfer on the chassis with forward momentum motion also has to be considered in brake sizing.

Same size rotor, pad, and caliper piston diameter ?