87 442 Rear brake issue

[85442/86buick]

if the adjuster is on wrong the shoes not expand and may even contract

wow i did not know that .
back to O.P's issue , what about the flex line to the rear end ? just throwing out there

 

[Mat1227]

All lines from the master cylinder to the wheels are new, including the flex lines. All stainless.

 

[Mat1227]

Finally got to look at the brakes today, changed ALL brake hardware, (springs, & adjusters) Everything that was on was correct and appeared to be functioning correctly, but I had bought the new spring kit and 2 new self adjuster kits, (R & L), installed took for a short test drive, still the same issue, right rear locks up. Had a thought, what if my calipers (front) are not working properly and is requiring me to push the brake pedal more than I should be. I does seem like I'm pushing it quite far, but I've not driven an older car for quite a long time, maybe it's normal??? There is only 3 parts left in the complete brake system that hasn't been replaced so far, master cylinder, proportioning valve, and calipers. Any help I don't really want to replace everything YET.

Mark

 

[pontiacgp]

how did you determine the brakes were adjusted properly and did you switch the shoes from left to right to see if the problem is the shoe?

 

[Mat1227]

I did not switch the shoes, did make sure the long shoe was on the back,

 

[pontiacgp]

I suggest you switch the shoes and drum and make sure you have them adjusted properly....

 

[truracer20]

Just a thought but what is the inner diameter of each drum?

 

[Mat1227]

Had some time today, decided to put new brake shoes on the rear, and start at the master cylinder bench bleed it, bleed all lines, adjust rear brakes, basically start at the beginning. What I found during bench bleeding the MC, with the little hoses attached started to exercise the piston of the MC, noticed something odd, I was getting a good flow from the rear port (rear brakes) but the front didn't seem to be getting as much flow, so I pulled the hoses out of the fluid to see exactually how much I was getting, started pushing the piston had good flow, for maybe what would be half the stroke, then the front stopped flowing at all, the rear still had good flow, I did this for about 10 minutes solid, the front port acted the same, flow only half the time, believe this is my real problem, so I order a new MC Amazon.com ordered a Raybestos brand MC. I did try and remove the snap ring that keeps the piston in the MC, with no luck. Since I ordered one already, wanted to see what was restricting flow to the front. Assume something is just plugged up, but the new one was less than $30 shipped, just bought it.
I'll keep this updating as I get this fixed.

Mark

 

[Mat1227]

Installed new rear shoes, all drum hardware, springs, adjusters, and Master Cylinder, bench bleed MC, vacuum bleed all 4 wheels, the my son came over and we did the traditional bleed "pump it up, crack loose the bleeder" several times on each wheel, brakes all work very good now. Bottom line, the master cylinder had either something blocking fluid for part of the stroke, or maybe the bore is wore and fluid bypasses the piston when it gets to a certain point. Either way, a new Master Cylinder was only $24 shipped.

Mark