gnx7

iTrader: (10)

So I tore apart the whole suspension and in doing so I painted the brake calipers, put in new pads, and a new master cylinder, braided steel brake lines from TriPoint, and Motul brake fluid. I bench bled the M. Cyl like instructed, put it on the car and then went to each corner in the proper order and bled the brakes.

Well when I bleed the rears the pressure feels great. When I move to the fronts to bleed them the pressure goes to crap.

I have bled them 3 times now and they still suck. I test drove the car and they are definately not right.

Does this sound like a case of poor bench bleeding of the master cylinder? Seems to me the fronts aren't holding pressure.

Do maybe the front calipers need rebuilding? Should I try bench bleeding the master cylinder again? What a PITA.

-GNX7

hypntyz7

Many times in my experience, especially on a 7 that sat parked for a while. the rear calipers stick. You can bleed all you want, replace pads and cylinders, and they remain stuck. You can even force the piston back in, but they remain stuck. I have went through this about 4 times now, lastly on my 87 t2 last week. IT sat for a year blown up.

The pedal worked but went to the floor. After a week of driving it around like this I noticed extreme amounts of dust on the front wheels only. THey also got hot easily. I finally switched out the rears with known working ones and it has a hella solid pedal now. I guess the only options in this case are to rebuild or replace.


Good luck!

gnx7

iTrader: (10)

I went ahead and bled the master cylinder (while on the car), the proportioning valve, and then all 4 corners again. Nothing has changed. This is getting really annoying. My 5th time bleeding the brakes now.

I am using a rebuilt Kragen master cylinder so now I'm going to buy a new Mazda unit and see if that makes a difference.

I could kick a 10lb lap dog thru a goal post with minimal effort with how pissed off I am right now.

Any ideas are welcome.

GNX7

james starnes

I recently had a similer situation with my nephews 87 rx. I was changing his pads on all four corners. His rt. front caliper was stuck and causing excessive wear to those pads. I pulled the caliper apart, lightly sanded the inside, replaced the inner seal and boot. Then bled the system per the maint. manuel. After all that the pedal felt mushy as you described. I bled and bled those puppies. No help. Finally I noticed that the small round portion in the mastercylinder just under the cap( it has an o-ring on it.) had fallen out when I added fluid during the bleeding procedure. I reinstalled it, and bled the brakes again. The pedal feels great now. Yes I felt like an idiot. So make sure that peice is installed properly, if at all, and check its condition. Good luck.

Icemark

Double check the booster too, if you are leaking or not stable in the vac feed you could be getting strange feelings on the brakes often mistaken for a leaky master cyl.

Of course that only applys while the engine is running