No brake pressure with torque, poor pedal feel

[mezje]

As per title I get no brake pressure when moving i.e. there is torque at the wheel. The brakes work and bite while the car is moving at very low speed (almost a stop) however when moving I feel the tiniest amount of pressure and then nothing.

I suspect it is the master cylinder and have one on order, but I thought I would throw this one to the brain's trust whilst I am away for work. I'm thinking the booster transfers pressure to master cyl but master cyl has an internal leak. Hence I feel a small amount of pressure that then dissipates.

Worth noting:

• I rebuilt my brembos when reshelling my car and moved on to the new one, booster and master cyl retained.
• There are no leaks and I have bled the system more times than I care to admit, using 1.5L of brake fluid (in a bid to fix the issue)
• https://www.ozvr4.com/threads/poor-braking-performance.15842/post-340028
  I can get pressure and exhibit what @Kaldek details here, so I don't think it is the booster.

Thoughts?

 

[Marko]

Had the same issue with my Brembo’s. Turns out I hadn’t bleed the brakes properly, there was another set of bleed screws on the inside of the front calipers. I had only done the outside and air was caught on the inside set of pistons. It was a rookie mistake on my part, but worth a look.

 

[mezje]

Had the same issue with my Brembo’s. Turns out I hadn’t bleed the brakes properly, there was another set of bleed screws on the inside of the front calipers. I had only done the outside and air was caught on the inside set of pistons. It was a rookie mistake on my part, but worth a look.

This is a very good point. I have definitely only bled from one point.

 

[BCX]

My rear calipers have a bleed for the inner cyl too.

When you bleed each caliper, start with the outer then move to the inner.

Wheel order:

1. Rear left
2. Front right
3. Rear right
4. Front left

 

[mezje]

My rear calipers have a bleed for the inner cyl too.

When you bleed each caliper, start with the outer then move to the inner.

Wheel order:

1. Rear left
2. Front right
3. Rear right
4. Front left

Yeah roger, had done that, just neglected the inner bleeders - amateur hour!

 

[Baba Galant]

My rear calipers have a bleed for the inner cyl too.

When you bleed each caliper, start with the outer then move to the inner.

Wheel order:

1. Rear left
2. Front right
3. Rear right
4. Front left

Is that the bleed order for our car's or only if fitted with Brembos?

 

[BCX]

Evo and galant have the same order.

The master cyl has two circuits, and its to do with bleeding a circuit at a time.

Rear left, front right are part of one circuit.
Rear right, front left are the second.

 

[Baba Galant]

Much appreciated BCX!

 

[mezje]

Well not sure if it was the master cyl or the fact I hadn't bled the inner bleeders.

Car now brakes as it should, almost ready for RWC and club reg!

There was a bit of corrosion on the booster and below but that could have been from previous brake fluid top ups, no obvious damage to the old master cyl and no leaks when I was checking it.

 

[Legnum in America]

Do we bleed the brakes with the car running?

 

[Baba Galant]

No, the pressures are too high and ideally all four wheels are off at the same time for access to front and rear calipers.
Are you pumping or using a mityvac set up?

 

[Legnum in America]

No, the pressures are too high and ideally all four wheels are off at the same time for access to front and rear calipers.
Are you pumping or using a mityvac set up?

Pumped first, went through about 750 ml of fluid so far Spongy feeling still. I did rebuild all 4 calipers and replaced the front lines to braided. My guess is air is still in the system. I did buy a handheld bleeder. I'm going to try that next.

 

[mezje]

No need for a bleeder, 750ml should be more than enough.

With a tube going in to a reservoir, I just pump to build pressure, crack the line, tighten and repeat.

 

[Baba Galant]

Pumping is hit n miss depending on who's pumping.
Do what BCX suggested and don't allow the master cylinder level to drop below half way. I run stock brakes just braided hose lines and it stops on a dime.
I've switched over to Motul 5.1 that handles more heat too.

 

[Legnum in America]

Pumping is hit n miss depending on who's pumping.
Do what BCX suggested and don't allow the master cylinder level to drop below half way. I run stock brakes just braided hose lines and it stops on a dime.
I've switched over to Motul 5.1 that handles more heat too.

I'm using liqui Moly 5.1

 

[Legnum in America]

Is there anything special in bleeding with the ABS system?

 

[Baba Galant]

Not that I've encountered.