Brake nightmare

[Inchworm]

I bought an old bomber that runs like a dream...

So long as I don't need to stop. It is a 1986 Olds Delta Eighty-Eight, front wheel drive.

I've basically replaced the whole system in the front with new master cylinder, 2 calipers, 2 rotors, and pads.

After installing we started the bleeding on the passenger side and everything worked like it should. The driver's side, however, is totally aggravating the hec out of me.

pump, pump, pump, pump, hold...

when I open this bleeder valve (sometimes) it shoots 1 squirt of fluid then nothing but slow oozing of fluid. It often does absolutely nothing -- to the point where the rotor is free in that caliper when the brakes are down.

So... we assume it is blockage and blow air through the line. Barely passing through...

We go looking for a "block" thinking that the valve in it is seized. The line went basically from the caliper to the master cylinder without passing through a block as we thought.

We decided to replace the rubber line between the caliper and the hard line thinking it may have collapsed. Bingo! I could not blow through the old rubber line. Wee! I am thinking once we get it back together this time we are done.

New line in... same crap.

Does anyone have any idea what could be wrong? I'm almost thinking bad new master cylinder, but the passenger brake is fine...

I'm goin nuts.

Thanks in advance for any suggestions.

:banghead:

[jimmil]

1. Did you test the hard line?

You definitely have a blockage but lets go through everything you need to do when repairing brakes. While replacing the soft line going to the caliper did you do a thorough inspection and test of all the hard lines going from the master all the way to the soft line? When you took the rubber line off fluid should have flowed easily out of the hard line. Somewhere there needs to be a split to activate both sides of the front (assuming no ABS). Did you bench bleed the master before putting on all the lines? I know this is redundant since one caliper works but it is a necessary step. When you installed the calipers did you clean and grease the slider on the brake mount? It has nothing to do with brake fluid flowing but it is still good practice to assure an even amount of pressure on both sides. When you bled the brakes did you bleed all of them? Old brake fluid is usually very badly contaminated so bleed them all until you can see new, clean fluid flowing. Also, when bleeding always bleed the brake that is furtherest from the master first and then the next furtherest and so on.

There is a blockage no doubt. I would disconnect the line at the master and at the caliper and blow air through the system. It may boil down to where you will need to run a solvent through the system to get it cleaned out. Use alcohol to do this. Afterwords, really blow some air through to evaporate any remaining alcohol in the system and use an entire bottle of brake fluid to make sure it is all out. If you need a new hard line I can go through that with you if need be.

[Inchworm]

2. I have to let you know what happened

The end result was that it was a bad "proportional valve."

Evidently that is what we called the block. They are little bullet things that hook to the lower parts of the master cylindar. My "bud" stripped it on day one. I learned a lot though.

I'm a master brake system dude now hehe

What I did after I posted was start all over and diligently watched over every step. It'll stop on a dime now.

Thanks!

~Inchworm

:hi:

[jimmil]

3. THE BRAKE PROPORTIONAL VALVE!

That never entered my mind but I certainly can see it causing the problems. I have put many onto cars in the past but those have all been race cars to balance front and back braking. It never entered my mind to check that. Great find! Now you can do brake jobs for all your friends too! Really, what you did was about an $800.00 job if you count parts. Brake jobs and air conditioning account for about 80% of the revenue car shops take in. Start your own sideline business.

[Inchworm]

4. Suhweeet!

Sadly I'd probably do it for hamburgers on the grill and a few beers :D

I love this car so far. It seems like it wants to go on a roadtrip. Idles along at 65 and needs open highway hehe

Thanks for your help jimmil.

:thumbsup: