brake bleeding problem: proportioning valve?

[1988_4wd]

Just bought an '88 4WD. I had to replace the brake line between the rear proportioning valve and the front brakes. Now, I am having trouble bleeding air out. Do I need to bleed the proportioning valve? The bleeder does not want to move, and I am afraid if I break it I must get a new one from the dealer at $122, and then replace the other two brake lines, which will no doubt also break. I suspect the master cylinder might also be a problem, so I may replace that first. How does one bleed the master cylinder - the chilton's book has no specifics on that.

 

[1988_4wd]

Thanks for the advice. I did bench bleed the master, and got it installed without incident. After soaking the bleeder on the proportioning valve every day for a week, I was able to open it without breaking it yesterday. So, tonight I have have help coming over to pump the brakes while I bleed.

 

[1988_4wd]

Well, I thought I had all the air out, until I started the truck and the power assist took my pedal that could only go half way to the floor (engine off) to just an inch off the floor. So, there must be more air in the lines.

I bled just as the book says - bench bleed the master before install, then bleed left rear, right rear, right front, left front, the proportioning valve. I made several rounds. No more air at any of the wheels. The bleeder at the proportioniong valve seems to be clogged - fluid only comes out at the threads (not the middle, as it is supposed to), so I bled there a lot, but cannot be sure more air is not coming out.

My dilema:
1. order the LSPV from Toyota for $122 and install it (along with several more brake lines I will break during install), and try to bleed again, with the assumption the LSPV is defective and cannot be bled correctly,
2. try to replace LSPV bleeder valve - although Toyota dealer does not carry that part either - so try to find at parts store. However, if I bleed through threads, I figure that should be okay, so this is probabably not problem.
3. take to mechanic down the road, and see if a power bleed at his shop will do the trick w/o having to replace LSPV.
4. Perhaps the rear brakes need adjustment to get me pedal. However, I see this as a remote possiblity.

Any suggestions?? Thanks in advance for any help.

 

[tnt40]

I have a 1985 4runner and theres a p-valve in the rear. It's on the pass/side rear. Just a thought. I had the same type of trouble. Good luck...

 

[1988_4wd]

Toynado: you were right, it was the rear brake adjustment. Apparently the bleeding went just fine.