Brake Issue

[lrquil]

Coach stops OK, but takes heavy foot pressure. Not sure if this is an air problem or if I need brakes. Anyone know what a brake job costs on a class A diesel?

[lrquil]

Well, this has been interesting. My wife wrote the original threads because I had not gotten around to it. (The coach is in storage, no harm, no foul). Yes, this is our sixth coach and four were diesel pushers. We were 'full-timers' for three years in a 41' Holiday Rambler. I familiar with air brake systems and operation, I had a CDL for about a year several years ago. After I retired, I drove a school bus 'to give back to the community', (or whatever). I always do an air brake check before operating any coach and that checks out OK. I have never had this particular problem with air brakes and while I do appreciate the positive replies and those who actually answered my question, I was shocked and dismayed at some of the condescension and vitriol. (My wife also knows how to do an air brake check, but we just bought this coach and she has not driven it yet...just sayin').

[wolfe10]

lj2654 wrote:
I have a 40' Beaver DP with air over hydraulic brakes and picking it up tomorrow after having all new front brake rotors, wheel seals, pads, calipers, brake fluid flush and bleed. New oil bath hubs and seals and new gear oil. The parts and labor is about $1700 for mine.

Are you sure it is not hydraulic over hydraulic? That is what Safari used for many years.

[bjbear]

lrquil wrote:
It's a 2002 National (Marlin) 300 Cummins w/a Spartan chassis. 89,400 miles. Not sure what the cut-in and cut-out pressure is. This is our 6th motorhome in 20 years, all but one had air brakes. We have had tire issues over the years but never a problem with brakes.

The following link is an excellent manual on air brakes. You may find it useful to go through it and learn about how to test the components in the system, do a pre-trip inspection, adjust slack adjusters, etc.....

https://www.mpi.mb.ca/en/pdfs/airbrakemanual.pdf

If you follow the steps, you will isolate your problem. Also, as others have suggested, inspect the drums for signs of axle seal leakage. Good luck and be safe....

[timjet]

FormerBoater wrote:
Your unit with a Spartan chassis has automatic slack adjusters.

They need to be calibrated periodically which is done from the driver's seat.

This involves fully stroking your brake pedal for 30 seconds or so, repeat 5 times.

Roll down your window, if you hear a clicking sound then your slacks are adjusting to restore your full braking power.

Often overlooked, simple to do and does not cost you a dime!

Videos are available on the web.

I would try this first.

FormerBoater is right, try this first. I go through this routine everytime at startup. Next call Spartan and talk to Big Mike. This will save you some money.

[azdryheat]

When getting a CDL there is an endorsement for Air Brakes that requires the applicant to take a special written test and to perform an air brake pre-trip check on a vehicle equipped with air brakes. Miss a step and you flunk. It's that important.

[lj2654]

I have a 40' Beaver DP with air over hydraulic brakes and picking it up tomorrow after having all new front brake rotors, wheel seals, pads, calipers, brake fluid flush and bleed. New oil bath hubs and seals and new gear oil. The parts and labor is about $1700 for mine.

[gutfelt]

As it is where I live mandatory to attend and pass a air brake course before your allowed to drive a air brake vehicle it should be like that everywhere in North america

[FIRE_UP]

lrquil wrote:
Coach stops OK, but takes heavy foot pressure. Not sure if this is an air problem or if I need brakes. Anyone know what a brake job costs on a class A diesel?

lrquil,
The short answer to your issue is, it could be a lot of things.

1. Improperly adjusted slack ajusters
2. Leaking oil seals on any one or more of the hub seals
3. Glazed brakes due to over use (too dependent on) the use of the exhaust brake and not using the service brakes on a regular basis
4. As Brett was alluding to, possibly low air pressure.

Now, for the bad part. Partner, without sounding too condescending or derogatory here, you maybe should park that thing and LEARN ABOUT AIR SYSTEMS and air brakes. You state you've had 6 coaches in the last 20 years and ALL BUT ONE has had air brakes and, you DON'T KNOW ABOUT CUT IN AND CUT OUT air pressure? Wow.

Sir, there's a lot going on in front, behind and underneath you when running a diesel coach. What I'm say is not meant for you to become a master diesel mechanic, not even close. I'm just saying due to you owning and operating a diesel coach, (and apparently 4 others) WITH AIR BRAKES, you really should know even some basics.

This will give you some operational knowledge on how your system works, when things might be wrong, or if your air system is building air properly and in the appropriate amount of time so that your brake system works as it's designed and, even things like low air warning, automatic spring brake air pressure, things like that. Again, not trying to belittle you, just saying that, based on your statements, you are unaware of even the basic things diesel coach drivers need to know to be safe. Good luck.
Scott

[wolfe10]

Come on guys, we get enough mis-information without trying for it.

Yes, the majority of DP's have oil bath front wheel bearings. And, yes if the inner wheel bearing seal leaks, it CAN soak the front brake components. Very easy to check visually if you are under the coach.

[gutfelt]

RedRollingRoadblock wrote:

gutfelt wrote:
he did say air brakes I doubt its leaking oil seal

So his bearings run with air for lubrication?

You bet its a great system :S

[RedRollingRoadb]

gutfelt wrote:
he did say air brakes I doubt its leaking oil seal

So his bearings run with air for lubrication?

[FormerBoater]

Your unit with a Spartan chassis has automatic slack adjusters.

They need to be calibrated periodically which is done from the driver's seat.

This involves fully stroking your brake pedal for 30 seconds or so, repeat 5 times.

Roll down your window, if you hear a clicking sound then your slacks are adjusting to restore your full braking power.

Often overlooked, simple to do and does not cost you a dime!

Videos are available on the web.

I would try this first.

[SidecarFlip]

Oil seals can leak and saturate the shoes. Happens all the time on big trucks. Only rakes a minute to ascertain by getting under the unit and looking at the edges of the drums and/or backing plates. If either are wet (showing oil), seals are gone and shoes need replacement. Dry brakes don't work well with oil soaked friction material.

Seals get old and brittle after a time and it's an '02 so it's probably time. Good news is seal replacement is inexpensive and so are new shoes.

[ScottG]

I buddy of mine has a 2002 Kenworth T300 which mayhave a similar and very common air brake setup. Since new, it took more pedal effort than it should have. Dealer said all was fine and my buddy is a mechanic and has checked every part of it.
After many years and one accident, he found out that the brake manufacturer was trying a new compound that had a tremndously long life but the pads were hard and had lousy bite.
After 150,000 miles the pads were still at >75% but he replaced them anyway. Braking was much, much better.
Since your rig was built during the same time, I would check out all the pressures and then if nothing else, replace all the pads/shoes - which are cheap.