57 3100 brake pedal stuck at top?

[tmoble]

So I'm driving home from work in my (owned and driven since 1983), I'm rolling up to the guard shack at the parking lot exit, hit the brake to wait for the arm to swing up and the brake pedal is like stuck at the top. Doesn't hardly move at all. results in the pic.

It's a stock M/C and pedal setup. What would cause this? is there some way for the linkage get over center or something? It's pretty simple. It's dirt simple. Truck still in the parking lot at work, get a wrecker in the morning.

I've rebuilt that M/C twice over the years, but I'm clueless.

[tmoble]

there'll be no laughing at my plywood sun visor either. I just used what I had handy.

BTW, this truck has an F-body front sub and C4 Vette rear. Lots of brakes, no previous issues. Just glad it didn't happen a minute later at the freeway intersection. A guy could get hurt.

[truckdude239]

the mc might have gone bad I'd replace the whole mc instead of rebuilding it. i've never had any luck rebuilding m/c or wheel cyilenders, sometime cheaper to replace it it too

[mr48chev]

Put a new mc on for sure this time. I'm not sure if the residual valve in those master cylinders can stick and cause that but that could be the case.
Otherwise I would spend some time under the dash checking linkage and making sure that something didn't bind up or a pin didn't slide over and catch on a bracket. Or something didn't fall down and get caught in the pedal linkage.

There is the possibility that the piston bound up in the bore but I think that and extra hard push on the pedal would get past that most of the time.

Was the windshield broken before or was that from hitting the guard shack cross arm?

[tmoble]

>>> hitting the guard shack cross arm?

yeppers. knocked that thing into the dirt.

It's a 57, no linkage under the dash. pedal doesn't pivot under the dash at all, goes through the floor.

[dicer]

So when you push on the pedal is there brakes? Ive seen wheel cylinders go to the extream and be locked by corrosion, and its like the brakes are on all the time.

The only stock item on these trucks that stinks is the master cylinder, you need the dual system type. But then I've seen them fail as well, like in an old rambler.

Could be dirt or what ever blocking a port.

If the brake lever isn't froze, that would be real rare, it must be a blockage or the aluminum (if memory serves) piston is cracked and expanding, and seized in the bore of the MC. And that could happen with a dual system I think too.

[mr48chev]

I take it that you drove it to work and it was ok with no brake problems? I'm still thinking linkage as in something is out of place. If the piston/cylinder were worn enough to bind up and lock up they would probably be worn enough to leak also.
Unless you had something flip up and smash the brake line on the way to work so no fluid would go though it.

[tmoble]

found it. The clip that retains the piston and stuff in the M/C broke, let the washer like gizmo fall out which then jammed the rod.

[tmoble]

even more fun, I was wearing short socks, my foot slipped off the left side of the pedal while I was kicking it, trying to dislodge whatever it was jamming it. Ouch, might as well be road rash.

[craig32]

Originally Posted by tmoble

>>> hitting the guard shack cross arm?

yeppers. knocked that thing into the dirt.

OK, better than I thought. I thought you hit something solid and your head cracked the windshield. Sure glad it wasn't that!

[OrrieG]

Ahhhh, the infamous gizmo failure. I had a wheel cylinder do that once. was up in the boonies, ended up crimping the line with vicegrips so I could limp back to civilation. No way I was going to walk 20 miles.

[tmoble]

I discovered a guy can crimp off a steel brake line with a big enough rock in a pinch. Yep it was about 20 miles out in the sticks west of Grants Pass, Or. Which is itself somewhat out in the sticks.

[Kabwe]

Sorry to read about your incident, but I'm glad you are okay. The truck can always be fixed, but with us humans that is not always the case.

[OrrieG]

Originally Posted by tmoble

I discovered a guy can crimp off a steel brake line with a big enough rock in a pinch. Yep it was about 20 miles out in the sticks west of Grants Pass, Or. Which is itself somewhat out in the sticks.

And hot if summer. In August we are going down to my Sisters place near Lakeview for some R&R and fishing.

[Panelman55]

Sorry that happened man!!! Does the "E" brake not work??? I've had close calls before and was able to use the "E" brake to save my but a least twice. I'm with the other guys I always replace and never rebuild brake parts, life is just to short.



Panelman55

[Wheelie]

glad your ok man. That sucks! That could have been waaaay worse. Did you get any splinters from your sunvisor? j/k man

[tmoble]

got a new windshield today, bought the re-pop rubber. it doesn't even resemble the original as far as the way it's shaped and the position of the grooves. I was unable to install it.

Anybody know about this stuff?

[1956chevtruck]

Originally Posted by tmoble

got a new windshield today, bought the re-pop rubber. it doesn't even resemble the original as far as the way it's shaped and the position of the grooves. I was unable to install it.

Anybody know about this stuff?

With the re-pop rubber it took me and a professional auto glass installer 3 hours and then finally we threw it out and used some generic rubber that he had. Never Again! Glad you're OK.

[tmoble]

Thanks, my ankle is getting better but my pride is still taking a hit.

I figured as much on the rubber.