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kb7uxe · 04-04-2014, 01:27 AM

Hello from Dan.
I drive a 1994 Winnebago Vectra diesel pusher with air over hydraulic...
It uses air to press a master cylinder.. ( there are 2 single systems )
one of them was leaking fluid from moisture collecting in the bottom, until the corrosion allowed brake fluid to leak past.
I could find no rebuild kits for the master cylinders.
on disassembly I find the corrosion too deep to clean up with a hone.
and the only place I could find replacements were either $1000 or a "suitable replacement " (fork lift )[http://www.powerbrake-drivetrain.com...-MASTE/detail] that would work for $500 each, so I bought 2 of them. ouch. replacement went well and they work ok.. pedal feel was some what spongy from what the other master cylinder were, you could still lock the 4 wheel disc brakes, but they still felt spongy. and just didn't feel right. after a year of searching, I did find a place that WOULD rebuild them for less than $150 each !!! stainless steel sleeve inserts !!! no more problem with corrosion !!! Welcome to Precision Rebuilders.com
I spoke to TIm Henderson at length on operations and options. he has been doing this for 40 years he said. very forthcoming with information and help. So I sent them my old ones, and with in 1 week I got them back.. I replaced the master cylinders back to the newly rebuilt ones, and WOW !!! back to wonderful pedal feel, and brakes that work like a cadillac !!
mind you the other ones work OK, and are a workable replacement, they just do not feel the same..
So if your brakes or failing you, call these guys, they will put a stop to bakes that don't work!
Welcome to Precision Rebuilders.com

Dan. 8-)

meyr · 04-04-2014, 04:38 PM

Hi, I am also the proud owner of a 94 vectra pusher. Your brake analysis peaked my interest as one of the few complaints I have with this coach was a very weak braking system. I also have the air over hydraulic setup, but had nothing to compare it to. I drive semi and am used to allowing plenty of room, but I had to extend what would be normal in a truck by quite a bit to get this thing stopped. There was no such thing as locking up these four discs at any speed. I've only owned this coach for a couple years and am learning a lot as I go. Last week I bought four quarts of dot3 brake fluid and pushed it through all the calipers and the stuff that came out was pretty bad. Without exaggerating, I believe I've shortened my stopping distance by 30% and are very happy at this time.. But I will save your thread in case I ever need to rebuild my masters. Thanks

kb7uxe · 04-04-2014, 11:42 PM

Hello meyr,
I wish you lived closer so you could drive mine and see the difference.
My brakes work as well or better than my car.
So I kinda am thinking they were replaced with the "usable replacement" master cylinder. And the OEM is slightly different. I'm not sure what is different, but I do know it makes a big difference in stopping power. I'd like to see the numbers on your master cylinder also to verify what they are. I think the center piston on OEM moves further than the "suitable replacement". The master cylinder uses a piston inside a piston. First time I ever seen it. I thought mine had air still in it etc and bled the heck out of the system.
to no avail. however, putting the OEM master cylinders back on fixed it. no problem.
When you push the peddle down, there is a second "spring" you feel. You should never get to that second spring as I think it's a "dump all air into the brakes" .. your welcome to msg me for more discussion about it if you have any further questions. I'll be glad to pass on any information I have. Dan.