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Did J30 brake upgrade, now my brakes don't work

Started by MoB pineapple · Nov 28, 2015 · 11postsSMF 2010–26

MoB pineappleNov 28, 2015, 4:11 pm · #1

Alrighty, so as the title says.
I upgraded my front brakes.
I bled the brakes, and the pedal goes straight to the floor.
There is no air in the line at all.
Replaced the master cylinder as well. (yes a bench bled it)

The rear brakes grab when the pedal is too the floor only to the floor not at all before that.
The fronts do nothing.

If you pump the brakes fast the pressure builds and holds but when you release and press back down it goes straight to the floor.
If you build the pressure and turn the engine on the pressure goes away and the pedal goes straight to the floor.

I would really love a solution, this is the only thing keeping me from having the car on the road.
Please help me posted image

sideways_s12Nov 28, 2015, 5:23 pm · #2

Brake booster? I don't know much about the J30 upgrade but I had a similar problem and it turned out to be the booster... It's worth a look if you haven't

MoB pineappleNov 28, 2015, 9:20 pm · #3

sideways_s12 on 05:23:54 PM / 28-Nov-15Brake booster? I don't know much about the J30 upgrade but I had a similar problem and it turned out to be the booster... It's worth a look if you haven't

The pedal isn't hard to push. The booster just makes the pedal easier to push down.
There is hardly any resistance.
Alex is dead set on the master cylinder being bad.

mcNov 29, 2015, 8:39 am · #4

i've had a lot of issues with "rebuilt" master cylinders....wasted so much time ...and brake fluid trying to get them to bleed....buy new.

MoB pineappleDec 2, 2015, 10:24 pm · #5

It's not a rebuilt.
It's brand new and doesn't work.
I'm thinking it's the master cylinder not being big enough

onephatserDec 3, 2015, 9:01 pm · #6

Are you getting fluid to the front calipers when you bleed the system? Next I would take the caliper off if you're getting fluid there and make sure the pistons are coming out. Not too far though or the piston will pop right out of the caliper.

Post Merge

I would start at the front brakes and work your way back to the master cyl taking all lines off and seeing where there is no fluid being delivered.

mcDec 4, 2015, 6:46 am · #7

...make sure you have mounted the calipers so the bleeders are pointing upward.

MoB pineappleJan 8, 2016, 12:39 am · #8

Replaced the master cylinder with a Z32 master and rebuilt the calipers.
Works fine now.

Cajun1guyJan 8, 2016, 10:54 am · #9

Alright! Time to get that biotch on the road.

sideways_s12Feb 13, 2016, 12:58 pm · #10

Nice! I need to do a brake upgrade myself I assumed you used the rotors as well whats he size difference? Wait those are 5 lug right?

8SixS12Feb 18, 2016, 7:47 pm · #11

I thought they bolted right up to s13 calipers.