Brake bleeding issue

[LFig]

I just replaced all of my brake lines, entire brake system including the rear drums, master cylinder, and proportioning valve. The only parts no changed were the booster and front brake calipers and pads.

I bled the brakes with another person pumping 5 times and holding. Fluid comes out in the first 2 times of this process but then the pedal is hard and no fluid comes out (I was able to take the bleeder fully out while the driver was still depressing the brake pedal.

If I run the vehicle after the pedal loses all pressure and then I am able to bleed them again but it does the same as before (bleeds on the first 2 tries and then nothing)

Confused about this. If anyone has had the same issue please inform me of how to fix this. Thanks in advance.

 

[Midnight LJR]

Did you bench bleed the new Master Cylinder? If so how did you do it?

Could you describe or more detail how you where bleeding the brakes exactly?

 

[mrblaine]

I just replaced all of my brake lines, entire brake system including the rear drums, master cylinder, and proportioning valve. The only parts no changed were the booster and front brake calipers and pads.

I bled the brakes with another person pumping 5 times and holding. Fluid comes out in the first 2 times of this process but then the pedal is hard and no fluid comes out (I was able to take the bleeder fully out while the driver was still depressing the brake pedal.

If I run the vehicle after the pedal loses all pressure and then I am able to bleed them again but it does the same as before (bleeds on the first 2 tries and then nothing)

Confused about this. If anyone has had the same issue please inform me of how to fix this. Thanks in advance.

Bleed the brakes again. Do not do the pump and hold. Simply open bleed screw, push pedal down hard and fast, hold at bottom, close bleed screw, let pedal up. This time do it with the parking brake off and the key on. Watch the brake light on the dash, if it comes on, close bleed screw, pump pedal until it goes off, resume bleeding. What is likely happening is the shuttle valve is being shifted and closing off the circuit with the leak.

 

[TJScott]

Would the Motive Power Bleeder help in this regard? I did my brake flush in about 20 minutes with one. I realize his is a little more involved. Just maybe the way to go?

 

[LFig]

If anyone has this issue I was able to solve it by connecting 1/4 inch clear tubing to the rear bleeders routing them into the top of the brake fluid reservoir. Then I pumped the brakes with the bleeders open until there was no bubbles visible in the clear tubing. Problem solved

 

[1TrackJack]

Do the quick bleeders fit our TJ’s? Do they work as expected?

 

[InOmaha]

I use tubing on the bleed valve and a syringe to create a vacuum. Open them, draw a vacuum, close reset syringe, do again. When fluid comes out, slow way down and draw it until the bubbles stop.

I've only replaced calipers though, not the whole system, so it had brake fluid in everything except the calipers already.

I had the tubing and syringe, if I didn't I'd have bought a specific hand pump vaccum made for bleading brakes by yourself. I've used my method 3 times on 2 different cars with success.

The tubing is clear tubing from a fish tank bubbler so I can see what's going on. When you do things without help you get creative.

 

[Goatman]

Recirculating the old fluid back into the master cyl defeats the whole point of replacing the fluid. Instead you are taking all the crap from the wheel and pushing it into the master where it can do even more damage. Any fluid pulled out of the wheel cyl/caliper should NEVER be reused. Ever!

 

[LFig]

Recirculating the old fluid back into the master cyl defeats the whole point of replacing the fluid. Instead you are taking all the crap from the wheel and pushing it into the master where it can do even more damage. Any fluid pulled out of the wheel cyl/caliper should NEVER be reused. Ever!

The fluid was brand new, just circulating it around to lose the bubbles. Not debris in the fluid. Not an issue

 

[LFig]

Do the quick bleeders fit our TJ’s? Do they work as expected?

Not sure. I didn’t use quick bleeders