Community Forums

cajunjohn · 11-01-2009, 01:34 PM

Just had back surgery and wondering if anything can be done to make braking on an older Alpine easier. When my back was 'presurgical', braking was hard....pressing on the pedal with all my might; now, it's impossible. Questions:
1. Is hydraulic braking just hard to do? (Read: push your foot through the firewall!) or
2. Is there something that can improve braking and ease the force needed to bring this behemoth to a stop?
Thanks in advance,
jt

takepride · 11-01-2009, 02:40 PM

JT:

There are numerous threads on hard breaking. Generally the issue showed up when WRV went with the adjustable pedals in '04(?). That had a lot to do with the angle and mechanics of the pedal's pivot, etc. Many found improvement by changing brake fluid and hydraulic fluid (assist), or by adjusting the pedal, itself.

The non-adjustable pedals stop normally, or should. Mine is as easy as my pick-up. Stops fine. Stops quick. Still weighs 15 tons.

I might add that the whole issue of Bosch sliding calipers versus Meritor four-piston calipers, a WRV recall and the new Workhorse recall probably relate to your problem. Have you checked which calipers you have?

How long since you've (or previous owner) changed the brake fluid? If that's okay, I'd say there is another problem.

Give the forum a search. You'll find a few years worth of threads.

EngineerMike · 11-02-2009, 09:13 AM

John- I suspect it has been a while since brake flush which on the Bosch caliper setups like yours is very important. Likewise pin slide lubrication is important for ease of operation. And in the next few months (per rumors on the Workhorse forum) there will be replacement calipers available to get rid of the sticky phenolic coated pistons within the Bosch calipers.

Assuming you get all the maintenance & recall-ish upgrades done, and still need more assist, you should have your hydraulic pump output checked at the brake input. You should be getting (IIRC, the actual spec is in the Bosch HydroMax maintenance manual on the ACA Tech Library page) ~1,000psi into the HMax for full brake assist. Could be that the pump isn't up to speed, as your complaint is unusual for your coach year.

cajunjohn · 11-02-2009, 01:06 PM

WOW! Thanks for your great answer, EngineerMike! I've watched you on the Forum over the last couple of years and I admire both your knowledge and your generous spirit in sharing it!
Thanks!
jt

Algoma · 11-02-2009, 05:19 PM

John,
As Mike said your complaint is unusual for the early Alpine brakes. Mine feel just the same as those in my car. I did recently have my hydromax unit replaced and that improved the feel somewhat. I am also using Dexron as originally provided for the hydraulic fluid. If your hydraulic pump is up to spec. and the brake pads are good I am not sure what else could cause the problem.

P.S. I believe the Bosch brakes that have caused problems were introduced in the 2000 coaches not 1999.

Renipladlo · 11-02-2009, 11:53 PM

JT - I can swear that having the brake fluid flushed out and having new fluid put in makes a world of difference on the pedal pressure. Mine are at least 100 percent easier to push down and get some action on the brakes. Had I been able to do the job myself, I would have also removed the brake assembly and worked the pistons in all the way reinstalled the unit and then pumped up the system. I believe I still have maybe one or two sticking, which I hope work themselves out. But the brake pressure is vastly improved, and I know I don't have to worry about moisture in the fluid with our long trip underway.

Loctite · 12-18-2009, 12:47 AM

Well, I have to jump in here and agree with cajunjohn. We purchased a 98 36' coach in August and on several occasions we've had to make quick stops. On those occasions I didn't think we were going to stop in time. I had the brakes inspected and was told that both the fluid and pads were fine. The one thing I don't know is when the fluid was last changed. I do know that the previous owner had all his maintenance work done at CNW in Yakima. They are in the process of sending me all the maintenance records for my coach.

From what's been said here I'm beginning to think that I probably need to have the fluid flushed and have the hydrolic pump inspected.

Old Scout · 12-18-2009, 07:33 AM

Not to hi-jack this issue but has anyone observed or "participated" in "flushing" their brake fluid? The newer 4-piston calipers have two bleed screws per wheel [inside and out]. Inside screws are reachable but bleeding the outside screws appear to require removing the wheels--has anyone seen a service center actually remove all four wheels to perform a brake fluid flush.