Brakes Will Not Bleed

[asoomal]

Hey guys, for the past 2 weeks I've been trying to tackle this problem I'm having with my car.

For the past 2 years, around every 1-2 months, I would have to top up the brake fluid, around 20-30 mL. A couple weeks ago, my brake pedal sunk to the floor, but when I pumped them the pedal would be nice and firm. So I tried to bleed the brakes, had no air except for rear right caliper. There were bubbles showing up constantly.


So far, I've replaced the Master Cylinder with a brand new Z32 one, removed ABS, rear calipers and the rear hoses, the calipers were kinda damaged and the hoses had never been replaced.

After using a MityVac to bleed all four corners, I would still get air in the rear right caliper, put some thread sealant on the bleeder, still air. So I used a hose with a check valve and managed to bleed it till no bubbles came out. I guess the MityVac must have been sucking air through the bleeder threads.

So for bleeding I have:

Bench Bled the MC
Gravity Bled all four calipers
Used a Mity Vac on all four corners
Used a tube with a check valve to bleed it

I've gone through 2L of brake fluid trying to bleed it

Also, the vacuum gauge on the MityVac slowly creeps down, from 25 to 20-21 when I bleed it and stays there.

The pedal is slightly firmer, but there is barely any stopping power, the tires do not lock at all on a wet surface.

Anyone got any tips on how to deal with this?


Thanks


EDIT: Stock brakes on all four corners.

[DanThaMan]

trace for leaks in the lines or at the fittings. When the pedal is retracting it is probably sucking air and when you hit the brakes it's pushing more fluid out. A small amount of air even just in the right rear line somewhere will effect all of the brakes ability to exert stopping power; Pascal's law

[OutToWinPAHC]

if your filling you have a leak. I bleed drivers rear, passenger rear, passenger front, drivers front. With a buddy and a lot of fluid, no issues.

[asoomal]

Spent another 2 hours bleeding them, pedal is softer than before when the engine is running, however they do brake better.

I was able to lock up my front left wheel on a wet surface, first half of pedal does nothing still.

I'm taking it to a shop tomorrow, it's impossible to see anything under there in my garage.

[Chaluska]

ive bled a million brakes in my life, are you sure your doing it right?

get a friend, and do it the good ol fasion way.

furthest away from the BMC first. passenger rear, drivers rear, passenger front, drivers front.

-loosen the bleeder
-push the brake pedal
-HOLD the brake pedal
-Friend tightens bleeder
-depress pedal (or pull up on pedal)
-repeat
-until ONLY fluid comes out (may take 20 times, depending on how much air is in system)


did you bleed the master cylindar???

[numbnuts240]

furthest away from the BMC first. passenger rear, drivers rear, passenger front, drivers front.

i don't remember on the s-chassis, but the passenger rear is not always the furthest from the bmc. iirc, the driver rear is the furthest on my s30.

[asoomal]

ive bled a million brakes in my life, are you sure your doing it right?

get a friend, and do it the good ol fasion way.

furthest away from the BMC first. passenger rear, drivers rear, passenger front, drivers front.

-loosen the bleeder
-push the brake pedal
-HOLD the brake pedal
-Friend tightens bleeder
-depress pedal (or pull up on pedal)
-repeat
-until ONLY fluid comes out (may take 20 times, depending on how much air is in system)


did you bleed the master cylindar???

I've bled a crap load of brakes, never had any issues before.

And yes I've bench bled the MC.

Thanks for the help =)

[OutToWinPAHC]

if your filling you have a leak. I bleed drivers rear, passenger rear, passenger front, drivers front. With a buddy and a lot of fluid, no issues.

DRIVERS REAR IS THE FURTHEST

[Chaluska]

hmm.. that is true eh? the lines run under the passenger side..

FML

Hope you can figure it out dude, i hate having a car that doesn't work...

[OutToWinPAHC]

Across the firewall down the passenger frame rail into a split, one to the rear passenger, the other across the car to the rear driver.

[troskinatior]

I had the same problem, it turned out to be the cailper. I think the seal was messed up

[asoomal]

Got it all done, wheels lock up with a little bit more pressure than before.

Bigger MC with stock calipers (will be swapping them out soon.)


Thanks for the help guys =)

[HerePiggyPiggy]

check your brake master cylinder. mine was leaking, barely but it still was leaking. mine starting failing and i replaced it asap cause brakes are "important." follow all your brake lines also just in case.

[asoomal]

Well the bigger MC doesn't have enough pressure, the Z32 requires less pressure to work, just more volume.

A small MC has more pressure than a bigger one, AFAIK.