I’ve read a bunch of threads and before I get a new master, figured I’d throw it to the group. New pads, drums, slaves, springs, soft lines on the rear, new calipers, rotors, hard and soft lines on the front. Haven’t driven it much since bleeding as I worked in engine stuff. Went out yesterday (90 degree weather) and all four wheels are locked up and the pedal is stiff. Any ideas? It’s an 86 FJ60. I’ve driven it maybe 50 miles since the brakes were done with no problems.
All brakes locked up, stiff pedal (1 Viewer)
- Thread starter jdizzle
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- Thread starter
- #5
Fluid level is full. Running DOT3 fluid. Jacked up all 4 wheels and all 4 are locked. Same whether running or off. I didn’t adjust the Ebrake when I installed the new brakes. The pedal is all the way out with maybe 2 inches of travel. It used to go down further.
if the master is stuck on, would opening up the hard lines at the MC, and then reveled help? Is this a common issue?
if the master is stuck on, would opening up the hard lines at the MC, and then reveled help? Is this a common issue?
I have never seen it happen in person or heard of it happening but the fact that all 4 wheels are locked makes me think of the one component that has the power to do so and that’s either the MC or booster. Guessing your booster was fine prior to the work so I suspect the MC.
you could try opening a bleeder valve on a front caliper and see if you get a blast of fluid out. You might have to bleed the system after but see if opening a bleeder brakes the pressure lock.
I’m wondering if you got a bad Mc and it’s bound up. But if that were the case I’d probably expect more slack in the pedal
you could try opening a bleeder valve on a front caliper and see if you get a blast of fluid out. You might have to bleed the system after but see if opening a bleeder brakes the pressure lock.
I’m wondering if you got a bad Mc and it’s bound up. But if that were the case I’d probably expect more slack in the pedal
fjc-man
SILVER Star
Are you sure that wasn’t diesel fuel in that brake fluid container? That would swell up every rubber seal in the whole system. It has happened.
If opening a bleeder or two doesn’t do anything I’d probably pull out the master and see if the wheels free up. If that does nothing I’d be looking for a pinched brake line somewhere but that’s something I’d file under very unlikely.
45acp
SILVER Star
Master cylinder. crack one of the lines at the master cylinder and see if that releases the pressure on the brakes.
Pushrod length is likely incorrect - doesnt sound like you've touched the booster/master/pedal though?.. eg: Brake Booster push rod adjustment help
Brakes can lock up if: the master cylinder is faulty, push rod from the power booster is adjusted wrong / extended too far, contaminated fluid or brake lines are clogged. Remove the lines to the master cylinder and your brakes should free up. You can then find out if the master is at fault or it's the booster push rod.
mongoose2231
Supporting Vendor
Hey, do yourself a favor and check the brake pedal adjustment and brake light switch. Make sure the pedal retracts fully. Mine had the same exact issue after entirely rebuilding the braking system. Turns out the brake light switch was adjusted at some point by po or whatever, and it did not allow the pedal to fully retract creating very slight drag. That drag then put heat into the system, thereby getting all wheels stuck and cooking the fronts to glowing red. Its a simple check and I would do that before anything else.
mongoose2231
Supporting Vendor
I went through all the troubles first, dismantling the master, replacing brake lines etc., only to find out it was the stupidest little thing. Start with the simple things first.
Not sure if the fj master cylinder has a relief port. If it does it is possible it is clogged with some debris causing the master cylinder to not allow the fluid to flow back into the reservoir. I had the same issue on my 48 plymouth. I removed the MC, used a small cylinder hone to resurface and flushed it out. Works good as new.
My Bad, Guess I should have said fj60...no FJ’s in this section
