Gumbo!!

itsbob

itsbob

I bowl overhand
This is a discussion we had awhile ago about brakes.

I stated that no harm could be done by pushing the calipers in and forcing the fluid back up into the reservoir..

You stated NO, don't do it.. unscrew the bleeder and force the fluid out the bleeeder valve. Your explanation was the fluid nearest the caliper was old, contaminated (likely) and dirty and I would be forcing that nasty crap back into the entire brake system..

I agree with your point, and learned the hard way how right you really were.

I don't know if you mentioned it, you probably did.. but in older cars (pre ABS) you were forcing the fluid back into the reservoir.. and yes probably contaminating the entire system..

BUT in ABS vehicle (AD: ABS Domini) there is a critical piece between the brakes, and the reservoir.. If you push back the caliper and force the fluid back into the system you are forcing fluid into valves the opposite way they were intended to work, AND probably forcing fluid they are inteded to stop, basically breaking the valves. If I do brakes the way I used to do it, I could possibly ruin the brake modulator, or at least a valve or twelve in the modulator.

Modulators run $1500 - 2500 not a cheap fix, and worth the extra couple of minutes to drain the fluid out of the bleeder.

I got lucky, prior to you posting the above I changed the front brakes in my Disco. I think I broke the shuttle valve inside my ABS modulator, but there is repair kit out there for that particular part.. it only cost $70, but I could of just as easily taken out the entire ABS modulator and been out $1500.

You gave out good information, thanks.
 
itsbob

itsbob

I bowl overhand
Oh, and all you Hummer owners, I believe you have the same ABS Modulator made by WABCO..

Plan on you ABS lights coming on, and being told it's a $2000 repair.. OR you can search online for the repair kit and do it yourself for $70.
 
K

kingmike2301

New Member
I've never had a problem with pushing the caliper back.. Ever.

The only thing you could possibly do is #### the pistion on an angle but that's about it.
 
itsbob

itsbob

I bowl overhand
kingmike2301 said:
I've never had a problem with pushing the caliper back.. Ever.

The only thing you could possibly do is #### the pistion on an angle but that's about it.
Click to expand...

That was my argument originally too, almost verbatim..

I've come to see the errors of my ways, and will never do it again.. especially NOT on a car with ABS. TO many valves, pumps, modulators that aren't designed to accept pressure in that direction..

Will add, I finally got the back tires off and bled the rear brakes.. my right rear caliper was a MESS.. getting it to start was like popping a zit.. Gunked up with all kinds of 'grit'.. had to pop through the bleeder to get it started, then all the fine grains suspended in the fluid.. surprised that caliper worked at all.
 
K

kingmike2301

New Member
itsbob said:
That was my argument originally too, almost verbatim..

I've come to see the errors of my ways, and will never do it again.. especially NOT on a car with ABS. TO many valves, pumps, modulators that aren't designed to accept pressure in that direction..

Will add, I finally got the back tires off and bled the rear brakes.. my right rear caliper was a MESS.. getting it to start was like popping a zit.. Gunked up with all kinds of 'grit'.. had to pop through the bleeder to get it started, then all the fine grains suspended in the fluid.. surprised that caliper worked at all.
Click to expand...

We probably do at least 10 cars easy a day. I've never had a problem :buddies:
 
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