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View Full Version : Brakes not working after Z32 Brake Swap?HELP!


Driven08
11-29-2011, 01:34 AM
I'm going to try to go into detail from what I remember.
To start, my car always had stock bmc and front 30mm Z32 calipers w/ ss lines. I did the rear ebrake set up with z32 calipers. I bought SS rear lines and after everything was bolted on(bleeders are all facing up), I installed a used 1" bmc that looked brand new on my existing booster. I then bench bled the bmc and started off bleeding from there.

After trying for a while, the front calipers wouldn't bleed and bleeders were completely dry(checked to see if they were clogged, ran a needle through them to be sure) and then I began again. Rear Z32 calipers work great but fronts don't do anything. I ended up rebuilding the front calipers and finding out the 1" wasn't working. I currently just put in a used AcDelco replacement bmc(1 1/16) and tried again(I have a brand new bmc on the side but I need the fitting so I didn't install yet btw). Now I did feed the front bleeders fluid and the fronts are now bleeding but the pistons on the front aren't functioning still.

I need help. What am I overlooking?

Cliff notes:
Installed rear z32 ebrake assembly, including calipers
Bench bled bmc
Rear's work, fronts don't grab(pistons stay in same position)
Tried another bmc, old one wasn't doing anything and I'm still in the same boat with the exception of the fronts bleeding but pistons aren't going anywhere.

rcdad123
11-29-2011, 02:25 AM
so fluid comes out of the front bleeders but the pistons wont push the pads against the rotors? the pistons could be stuck in the bores. is the brake pedal height normal or does it sink to the floor? if the brake pedal is pretty high when your standing on it and the pistons still dont work, they are stuck on the bores.

Driven08
11-29-2011, 02:35 AM
Pedal is mushy. Front calipers worked great before rebuild. They just weren't working after I did the swap. I rebuilt them to reassure myself they were fine and all the pistons looked fine. No scoring.

Sileighty_85
11-29-2011, 08:32 AM
didnt ready all of it,

Make sure bleeder valves are pointing upward

Driven08
11-29-2011, 10:56 AM
Yeah they are facing upwards. Next step I'm taking is buying a Might Vac and hopefully that solves the issue. Should just be air in the system

Adio
11-29-2011, 10:58 AM
What disc are you using?

Memberofthe600hpkaclub
11-29-2011, 11:14 AM
Urhmm did you start bleeding at the right rear then left rear then right front then left front

Driven08
11-29-2011, 05:07 PM
What disc are you using?
slotted 30mm fronts and slotted rear z32 rotors

Urhmm did you start bleeding at the right rear then left rear then right front then left front

Yeah I did that then moved to the fronts to try to focus on why they weren't working. I'm trying the Mighty Vac Tonight though

EDacIouSX
11-29-2011, 05:11 PM
how did you rebuild it? Did you take the caliper halves apart and rebuild that or just swap in new bushings and pistons?

Driven08
11-29-2011, 07:49 PM
how did you rebuild it? Did you take the caliper halves apart and rebuild that or just swap in new bushings and pistons?

Took pistons out while calipers were assembled, removed seals from inside,Dissasembled calipers, installed new seals and lubricated them with brake fluid and put it all together.

Driven08
11-30-2011, 12:15 PM
ok so problem solved. Bench bled the bmc again and used the Mighty Vac for a while on each calipers starting on the right rear and moving all the way around. Brakes are now fully functional but still need a little bleeding.