Workhorse ABS Controller

[MarkCoburn]

GMC thinks that I need a new ABS controller for my 2004 Brave 30' Workhorse.

No ABS light, no fault codes, however. Sometime, right before I come to a stop, I will get an unneeded ABS pulsing and it will significantly increase my stopping distance.

I've only had the rig for a few weeks. When I test drove it, I thought that I sensed something, only once. That is one reason that I paid to have a pre-purchase inspection done by an RV shop. I even specifically asked them to check the breaks and told them about what I observed. They drove it and said all-good. They also said that it was one of the nicest used coaches they had seen.

After I bought it and drove it around a bit, I became more convinced that something wasn't right. I took it to GMC shop for a checkup. Again, I told them what I was experiencing and again they said that they could not reproduce.

The first time that I came to a stop while leaving their shop, I noticed the ABS event.

I took it back today, took a tech for a ride and demonstrated. Then he drove it and said, yep... ABS is kicking in for no reason. They plugged in the scan tool and it said that the system was uncalibrated. They tried several times to calibrate but it said that calibration failed.

The end determination is new ABS controller needed, if they can find one, it will be $1700 installed.

These things are dead easy to replace. I've done it in other cars. I just don't know how to find a referb/used replacement part. GMC refused to give me a part number.

I'm wondering if I should go around and clean the sensors and check all the connectors.

Any advice?

[SmilingSimon]

now that you know how it acts, why not test on wet surface to see if it works when it should, if so then just live with it until it acts worse.


since the tech can only read a screen, nearly useless imo, then why not check the abs sensors on each wheel - plus connections to same ?



guess what, you can certainly LIVE w/o abs, but just be aware it may go away and brake & drive accordingly - $1700 is a bit of $$ (would pay for lots of miles of fuel), spend it if you must, but likely mo to it than just the controller, there are sensors and abs rotors on each wheel, all can be faulty and be screwy !


GL!

[MarkCoburn]

Thanks for the reply.

We where actually on the road when you sent this. I just pulled the fuse for ABS and drove without it. It was actually better (safer) to go without it than how it was acting. I'm planning to check the sensors and connections, maybe try to improve some of the air gaps for the sensors.

I've got a new break-related problem that I'll start a new thread for. I get the ( ! ) indicator and buzzer whenever the auto-parking-break is on. That is really annoying because it is on whenever the coach is in park. The parking break seems to work, I cannot make the indication happen with normal breaks, the break fluid is still topped-off.

When I find the solution to the ABS, I'll post it back here.

Originally Posted by SmilingSimon

now that you know how it acts, why not test on wet surface to see if it works when it should, if so then just live with it until it acts worse.


since the tech can only read a screen, nearly useless imo, then why not check the abs sensors on each wheel - plus connections to same ?



guess what, you can certainly LIVE w/o abs, but just be aware it may go away and brake & drive accordingly - $1700 is a bit of $$ (would pay for lots of miles of fuel), spend it if you must, but likely mo to it than just the controller, there are sensors and abs rotors on each wheel, all can be faulty and be screwy !


GL!

[MarkCoburn]

I think that I found the answer to this indication. Sounds like my auto park break is over traveling.

Originally Posted by MarkCoburn

I've got a new break-related problem that I'll start a new thread for. I get the ( ! ) indicator and buzzer whenever the auto-parking-break is on. That is really annoying because it is on whenever the coach is in park. The parking break seems to work, I cannot make the indication happen with normal breaks, the break fluid is still topped-off.

[SmilingSimon]

btw, a friend had brake issues and we found out his ABS sensor had melted due to braking down hills from heat we guess, but his front brakes were really in bad shape - he lives in oregon so rain rain rain and lack of mtce.

we were in calif at time and he ended up having to replace the front brakes/rotors and abs sensors (in calif they must check fix ALL brakes/all wheels by law) so he spent nearly $1000 on something that he w/ some help from me could have done for less than half the price.

rear brakes on mh are generally you have to pull out the axle to replace rotors and is non trivial whereas pads are no big deal (pulling wheels are PIA), so ALWAYS keep rear pads in good shape to save your rotors !!

as to your auto parking brake, it has its own fluid reservoir and you need to check it - should be under 'the hood'.

if you have a j72 auto brake, it has a couple ways to activate/operate, i sometimes 'catch' mine and it seems to do the 2nd method sometimes - but normally does normal activation method.

GL

[MarkCoburn]

Previous owner had a big break meltdown and had a bunch of break hardware replaced, including sensors. I'll have to look to see if it is just the front or the rear as well. I think that I need to learn how to get to the rear break ABS sensor to clean and adjust. I think that maybe there is just one? A tech told me that the ABS on mine monitored 2 front sensors on 1 for the rear axle.

[Mbowen2]

I think I am having the same brake issue with my 2004 Winnebago Brave 32V that I recently purchased. ABS kicking in when not necessary. When going down hill and braking before an area where the speed limit reduces near my home, I feel a shudder. Not always though. Took a ride on the freeway to an area about 3000’ higher than my home and then back. Didn’t feel it at all on the freeway.

No ABS light comes on. Previous owner said nothing about having any brake issues.

Did you resolve your brake issue?

I don’t have the auto parking brake. My RV has the Allison transmission.

Thanks in advance for any help you can give me.