I have a 1933 Plymouth deluxe And after driving it for 20 minutes or longer all 4 wheels lock up and brake light comes on Can anyone tell me what the problem could be that all four brakes lockup
It has all stock brakes I replaced all the brake cylinders And master cylinder ran fine after that for the summer last year and now this year they are locking up all four corners But when the brake’s lockup if I loosen the brake line at master cylinder it frees them up So I’m wondering if master cylinder could be bad
Do you have a return spring on the pedal? I have seen this happen when the return spring was missing, snapped, or lost its tension. The master cylinder piston does not fully return, allowing the brakes to drag, heat up, and lock.
Did you replace the flexible rubber hoses? when they age the brake fluid over time can start to dissolve & soften the inside of the hose and they can collapse holding pressure, when you open the bleeder they will open back up. HRP
If I remember correctly, the brake light switch on a 1933 Plymouth is on the master cylinder. He says that the brake lights are on when this happens. A collapsed hose that locks the brakes after it would not turn on the lights, I would think.
I did replace the front but not the back But if a hose is bad Would that make all four brakes lockup shouldn’t just one lock up with a bad house
Unless I am drinking decaf and not thinking clearly, I believe that it would just be the brake or brakes ***ociated with that hose.
Double check the pedal pushrod adjustment in any case. I have also seen jam nuts come loose. Once free, unlocked threads can do all sorts of strange things due to vibration. You should have a little free play.
The brakes lock up when pressure is applied, that would activate the brake light, taking you foot off the brakes doesn't release the pressure if the are locked up. I would suggest replacing to old hose. I have had experienced this with a Falcon in the past. HRP
Your pedal push rod is probably too tight against to master cylinder piston. Loosen it up to give about a quarter inch of free play before it touches the piston. If that doesn't fix it the relief hole in the master cylinder is plugged. It's a pretty small little hole that lets the pressure off the system. Brakes with this problem lock up because of this when the fluid warms up and expands. Can be very dangerous to drive until it's fixed.
This exact problem happened on Sean's T, I noticed the lights staying on and he said the car felt low on power (brake drag on all 4 wheels). OP adjust your master cylinder pushrod and check the pedal return spring for condition, the entire system is pressurizing because the fluid cannot return to reservoir and the fluid is also getting hot making the problem worse, the switch being closed and turning on the lamps is the giveaway.
I've had this issue also. New Master cylinder, complete new brake system. Worked great. Master was under the floor. The car sat outside all winter. Next spring when I got the car out, I had the same issue you're describing. Pulled the master after multiple attempts to fix everything. The master had a cast bore, no liner, and it had a lot of rust in it. I changed it, and all was good.
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