Brakes lockup won't release. Any ideas?

[Dirt Rancher]

Got the rebuilt rear axle installed with the SSBC rear drum to disc conversion. We also changed the master cylinder and removed the pressure proportioning valve. We have bled the system throughly. For some reason the brakes won't release pressurized fluid back to the brake reservoir sometimes and lock the brakes up. Have been bleeding fluid at the calipers to get them free again. Anybody got any ideas??

 

[WJCO]

Get the brakes to lock up again. Then manually disconnect the master cylinder from the booster (2 bolts). Then see if the brakes release. Sometimes when replacing master cylinders, the booster pushrod has to be adjusted. It could be keeping mechanical pressure on your master cyl. Just a thought.

 

[MBezner]

Bingo. Brian adjusted the master cylinder this morning and we are on a test drive now. Hasn't locked up yet.

 

[WJCO]

Cool. Hope it turns out to be a long term fix.

 

[Dirt Rancher]

I had adjusted the push rod as per the conversion instructions but the push rod length was way too long. Instead of turn it 1 turn out; I am now 2.5 turns in from where it started. I finally found a brake booster push rod gauge to get it set correctly when it comes in . . These things are pretty damn hard to find!!!

 

[WJCO]

I bet. You hardly have to do that anymore. I only suggested it because I had seen a couple in the past and had that same problem. Most of the newer ones are just plug and play though now.