I just completed a 3 year build on a car, and its ready to go on the road, and the last thing was to bleed the brakes.

Low and behold, the very last thing i need to do, and something is screwed up.

On this car deleted the ABS, and installed new lines with a proportioning valve to the rear. There is no leaks in the system. I've looked over all the fittings and there is no fluid bleeding out. I bled each wheel 4x, and probably ran 2 cups of fluid out from each caliper using my vacuum pump bleeder. And no, I never let the reservoir dry up, before you ask.

So naturally I thought it must mean a bad master cylinder. So, I bought a used 99 spec from Fritz, and put it on, and I am still getting the same results... almost no pressure. UGH!

If i pump the brakes 30 times, then crack any of the calipers its like there i no pressure building in the lines. I don't get it.

With two different masters I get the same results. There are air bubbles rising up through the fluid in both master cylinders when pumping brakes

Anyone have a similar problem? What should I look for! thanks!


Here is a picture of my lines, this is with the original master, before I swapped out to the 99 spec. the only thing i did different is the rear output of the cylinder is T'd and going to my front brakes, the front is going to the proportioning valve, and then to the rear using the stock underbody line

 

Did you bench bleed the master cylinder?

 

Yep... But even if I wouldn't have, with how much fluid I pulled through it would have had to fill the cylinders I'd think

 

still air in it. bleed it at the master again. once done go back to the RR corner, open the bleeder then have your helper push the brakes down. do this 5-7 times. then have him pump the pedal/hold/release pressure at bleeder. do this at every corner.

 

You will know if you are building pressure because the pedal will become very stiff. Initially, you will have a soft pedal. As you bleed the other calipers, you will feel the pedal becoming firmer.

The fact that you can pump 30 times and see air bubbles means you still have air in the system.

Use boosted414 procedure.

 

Do the old school method with a friend or you can make a one man bleeder with a bottle, extra brake line, and some vacuum line.

 

If you didn't bench bleed it (properly), it will take a LONG time to get the system right. If you have some extra brake line, just do this:

https://www.rx7club.com/3rd-generati...7/#post9459707

 

bench bleed again and then bleed all the calipers and the clutch. A Powerbleeder works wonders.

 

So, i made a hard line bench bleed line setup and rebled the master cylinder. Then i went to the back passenger side and using my vacuum bleeder pumped about two cups worth of fluid through. Then I did the same on the rear drivers.

Went up and pumped the brakes 30 times and still have ZERO pedal pressure.

Are the front and back cylinder chambers seperate, so could i get pressure in the back and not the front?

I am so frustrated at this point.

 

Forget the vacuum bleeder.

Pump the brakes 5-7 times then have a friend open the bleeder. Close the bleeder. Then release the pedal and pump the brakes again. Repeat this process until fluid under pressure is coming out. Go to the other wheels and repeat.

Pumping the brakes without opening the bleeder with the pedal down is wasting your time.

 

This. The hydraulic pressure is much greater than any vacuum or pressure bleeder will provide. The vacuum and pressure bleeders are great once you get all the air out of the system, but until then, they aren't all that useful.

 

Agreed. Best way to bleed brakes is the old standby, especially if you have a system that's been fully opened.

There is a power bleeder that holds fluid and connects to the brake master that pressurizes the system and makes sure you don't run the master dry. Using that in combination with a friend pumping the pedal is a great way to do it. Speed bleeders also help a good deal.

Dale

 

The front and back chambers are separate in the master cylinder, there is a little valve in the front chamber that commonly gets stuck if the master cylinder sits for a while. If you can get fluid to pump out of the rears but not the front or vice versa depending on the way you plumbed the lines then that is the problem.

 

i installed a reman'd 929 cylinder today and had my dad help me bleed it. got brakes! woo thanks for your help everyone