stiff pedal

[Dude its Robert]

After driving around braking the pedal gets stiffer and stiffer. It eventually gets to where the shoes are rubbing and it slows down as if im pressing the pedal. If I let it sit the pressure goes away (like when I get up in the morning they work fine)

 

I took off the front drums and regreased the adjusters then bled them. I drove a little and they seemed better but I haven't really tested it yet.

Do you think that will fix it or is the problem bigger?

[datzenmike]

Check the peddle free play. Push down lightly with your thumb on the peddle rubber. It should move about 2-3mm or 1/16" or so before the peddle pushrod under the dash contacts the master. If there is no play the master cannot return fully to it's 'at rest' position and fluid and pressure can't be released and is trapped ahead of it holding the brakes on.

[Dude its Robert]

Okay ill check when I get home. Thanks

 

[Dude its Robert]

If that's what is happening how do I fix it?

[datzenmike]

Well up under the dash the push rod can be undone and adjusted for length. Not sure this is it but should be eliminated and doesn't cost anything to check.

[Dude its Robert]

Okay I ready how to do that on another thread so ill have to adjust thar as soon as I can. Thank you so much

[datzenmike]

Not sure this is it but should be eliminated and doesn't cost anything to check.

[banzai510(hainz)]

This happen to me recently

 

I had a faily new brake master installed.

One day it just slowly started pumping up. everytime I hit the brake. By the time I got to my parents(halfway home point) it was heating my brakes up bad. all 4 wheels)

I hit the brake blleder in driver sie back and it released all the pressure. Took drums off and ck rea. all ok

 

4 or 5 days later it did it again but worse. I had a wrench and realse the blled screw and tighten it . Was ok till I got home and aI swapped out the master cylinder with a new spare I had at home

No proplem since.

 

Also I dont know how long you owned this 521 but Most 521 master cylinders need the threaded shaft that goes to the pedal cut about a half to 1 inch as when installed it pushed on the back side of the pedal arm thuse pusing it in as you mount the cylinder flushe with the fire wall. Its actuall is already pusing the cylinder in. so the threaded rod is too long compared to the stock Nabco/Tockiko one installed.

 

If you have a 521 best to buy 2 of masters. brake clutch and 2 slave cylinders also. wheels cylinders too. when you can

[Dude its Robert]

I just got it so I don't know a lot of its details. But if adjusting it doesn't work ill try a new master

[Rays74]

If all your MC adjustments check then take a quick look at the return port in the MC and make sure it's not clogged. IF it's not clear, you will see these similar symptoms.

[dr.feltersnatch]

also change your fluid. i have never seen it happen on a car but i have on bikes. brake fluid will absorb moisture from the air, and your brakes heat up the fluid causing the water to turn to steam, creating pressure in your lines.

[datzenmike]

... but if the master is working and adjusted properly the built up pressure will just push fluid back into the reservoir.