so i have a 1985 pickup with the R. i am running 36 14.50's so i decided to go with the front brake upgrade and switch to the 89 calipers and the land cruiser roters. anyways the truck has had the braked disconnected for about 4 months totally dry. i have bleed about 2 full size bottle through and don't seem to get anymore air. i have even vacuum bled the damn things. and the brake petal still goes all the way to the floor with just slight back brake. so i changed out the master cylinder. well now my back brakes won't even work the way they did before. i fully bled the new mc and am totally stumped on what i might have done wrong or why the brakes work no longer. they work ok not great before i started this whole project.

i need help oh and advice on the truck would be nice too

 

Did you bleed the load sensing valve in the back ?,if not, you probably still have air in the system.

 

i second that ^^ also did you adjust the rear brakes?

 

I just had to replace the MC and bleed the brakes on my 87 truck. It took us bleeding the brakes the old fashion way to get all the air out, the vacuum bled did not get the air out.

 

I too am having brake issues after replacing the MC. What is the load sensing valve in the rear and how to you bleed it?

 

The load sensing proportioning valve compensates for extra weight in the rear end. You will see brake lines running to and from it. It has a bleeder plug just like your brakes. It will look something like this:



Be sure to bleed in the correct order (not sure, you'll have to search; I found it on here somewhere).

 

Thanks,
I would have never known to have bled that.

 

Did you bench bleed the master cylinder after allowing it to run dry?

 

the bleed sequence is left rear, right rear, right front, left front, lspv

 

So who is ready for a laugh. Well I did the Bigger brake conversion and it turns out the brake are not switchable from side to side. My father put the brakes on and did. Not even think of seperate sides. I noticed last night and decided to look in the repair manual and see the picks witch showed the bleeder on top. Well anyways switchedsides rebled and holy George it worked. Thanks for all the help

 

i had prob with rear load sensing valve found it was fubarred,so i purchased a adjustable proportioning valve