brake weirdness... If it aint one thing, it's another.

[jocko]

So, the good news is that the T5 test drive went great! Shifted like a dream, and even zero engine oil leaks (had a busted oil pan drain plug that fixed with some teflon tape and crossed my fingers), anti-freeze leaks (busted the wp seal, so replaced it with a pump fill of metal flash and luckily discovered before I ran the motor, then replaced that pump and had a gasket rip and leak all over the place, then put ONE MORE on, and now it's good) and, best of all, no transmission leaks. New d/s fits great, yada yada yada.

And driving the T5 was GREAT, really happy with it.

But...................................

When I return from my test drive and check for leaks and find none, I was pretty tickled about that, and decided to slightly adjust the parking brake because I was pretty sure I had put it back on with a little too much preload and when I pulled into my garage, it seemed like the truck was struggling a little against the brakes.

So, loosened up the parking brake - tried to drive it and felt like the brakes were LOCKED. Jacked up the rear end and sure enough, both tires locked. Parking brake completely released and confirmed the cables were moving at the rear brake with the e-brake handle. Hmmm.

Happened to jump back in the truck and noticed the pedal was rock solid. Could not depress it at all. Tried to jiggle it pretty hard, finally got to where could move the wheels a little, but still extremely difficult.

There were NO changes made to the brake system during the trans install other than adding about 1/2" of fluid before the test drive.

So, here is where I'm stumped.

My assumption is that the piston is hung up in the master cylinder.
BUT - if that were the case, wouldn't there be slop in the brake pedal until the push rod impacted the stuck piston? If it were stuck in the fully aft position such that the brake pedal was fully seated against the under-dahs stop (which it is) then it seems there would not be excess pressure on the brakes keeping them locked!?! Again, if hung up fwd in the master, seems the pedal would have some un-opposed slop in it until the push rod hits the mc's piston.

I loosened the mc from the firewall (loosened the bolts until almost removed, but not quite). Push the brake bedal and the master cylinder moves away from the firewall until it hits the bolt heads exactly in sync with the brake pedal - in other words, zero piston movement in my mind.

Ok brake experts, tell ma whatcha think! I already have the parts around for a dual master swap like Chief Rocka's project thread, but gotta go on travel soon for work for over a month, really just wanted to drive this frickin thing after it being on jacks for the last 3 months doing the trans swap. So, may just take apart the old single master and see what's wrong, probably nothing a good honing/sleeve if req wouldn't fix.

Thanks in advance guys.

Jocko

[Deryl]

I would go ahead an swp it if it were me. You already have the old one loose! Are the front brakes locked too. I would check that befoe going any further. Good job getting the bugs worked out.

[jocko]

Was gonna check that but gotta get up at zerodarkthirty tomorrow so calling it a night. I am assuming they are locked also - but good point. Was gonna drop my driveshaft to make sure my new trans wasn't locked up(!) but then felt the brake pedal and it was rock solid hard - could barely push it at all, let alone full stroke. Really weird. Thanks for the reply - I probably will try to move them before I proceed. And I just got it off jack stands for the past 3 months!! Ha. I've had some leak issues with this mc anyway - so I guess my dual mc project will just have to happen sooner than I wanted it to.

[kieth]

Originally Posted by jocko

Was gonna check that but gotta get up at zerodarkthirty tomorrow so calling it a night. I am assuming they are locked also - but good point. Was gonna drop my driveshaft to make sure my new trans wasn't locked up(!) but then felt the brake pedal and it was rock solid hard - could barely push it at all, let alone full stroke. Really weird. Thanks for the reply - I probably will try to move them before I proceed. And I just got it off jack stands for the past 3 months!! Ha. I've had some leak issues with this mc anyway - so I guess my dual mc project will just have to happen sooner than I wanted it to.

a dual master cyclinder only cost 20.00 no biggy, but you will need a proportioning valve and some new line...

[TR65]

Jocko,

Might crack one of the bleeder valves and see if it releases brake pressure. I know that the system can lock up if the brake pedal rod is adjusted too tight, but I know you didn't change that. Just a thought.

TR

[jocko]

Originally Posted by kieth

a dual master cyclinder only cost 20.00 no biggy, but you will need a proportioning valve and some new line...

I already have a 67 C10 dual mc to put into it. No prop valve required since it's a drum/drum setup. So that's probably what I'm going to install. TBD if I install the booster at this point. Already have Capt Fab's bracket, so I believe I will now that I have the 3-on-the-tree linkage out of the way with the T5 installed. Just in time!