Spongy Brake Pedal

[vertigo]

I have replaced my brake shoes, pads, rotors, passenger wheel cylinder and caliper, master cylinder (bench bleed properly), and bleed the whole system (until clean brake fluid came out of each), and I still have a spongy pedal. Also I can't lock up my brakes when I slam on them...

What could possibly be the problem? I was thinking maybe the proportioning valve?

[Lee H]

Assuming all the components are correct......You still have air in the system.

[vertigo]

Hmmm, would it be worth it to take it to a shop and have them use their brake bleeding machine?

[Lee H]

That is an option. If it's not your DD, I would let it sit for a few days. Then try again. I've had success pumping them slowly and then gravity bleeding them a few times. With the cap off the master gently tap on the master and see if any air bubbles come up through the fluid.

[SS Tim]

Did you bleed them by the manual (chassis service manual section 5) and did you isolate the prop valve first? Are the shoes adjusted properly? They need to be pretty close.

[vertigo]

I will try that and let you know how it goes. Thanks!

[cdowns]

Originally Posted by vertigo

Hmmm, would it be worth it to take it to a shop and have them use their brake bleeding machine?

a better idea would b if you had the correct service manual and bleed the system the way they were designed to b bleed// like clamping the pin for example

[vertigo]

I did isolate the proportioning valve first and I just bled the furthest from the master cylinder first to the closest. The shoes are adjusted properly as well.

[SS Tim]

Originally Posted by vertigo

I did isolate the proportioning valve first and I just bled the furthest from the master cylinder first to the closest. The shoes are adjusted properly as well.

Like I said a little earlier the shoes need to be pretty tight. It looks like your problem may be in your bleed order. Start at the M/C if is dry or replaced then the closest to the furthest bleeder. That would be LF, RF, then the rears.

[buckskins4ever]

If you have properly done your bleed, and you know for sure you have solid fluid coming out of all four.............then I would really consider looking at your brake booster. No air in the lines, solid fluid, but still spongy pedal.....bad booster or leaking seal in the booster.
Take you booster Vacuum line off and try to get a scope look into the booster for fluid.

[vertigo]

But shouldn't I still be able to lock up my brakes when I slam on them even if the booster is bad?

[buckskins4ever]

if the booster is bad you wont have enough pressure build up to lockup. I had the same issue right after I installed new MC, bench bled, power bled all lines and still had terrible brakes. Found the fluid in the booster.

[vertigo]

I'll take a look at that too. Thanks for the responses guys.