My car had been sitting a year or 2 before I bought it. The previous owner said he never had an issue with them. I got the car running last week and went to back out of the garage. It took all I could do to get it to stop. Here are the details. Some might matter some might not. 4 speed car and the clutch pedal sits higher than the brake pedal. It is a disc drum setup with a power booster. Pedal pressure does not change when you start the car. Pedal does not drop when you start it. Pumping doesn’t do anything. Booster looks new. Rubber lines to calipers look fairly new. Where is ground zero to start on this thing. I do not think it was originally a disc brake car. Fluid is full.
1970 Duster won’t stop.
- Thread starter Toqwik
- Start date
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Jax_1975_Dart
Well-Known Member
I would inspect the hardware on all 4 wheels. You might as well adjust the 2 rear drums to point where it’s getting resistance when you spin the wheel by hand (rear end jacked up/off the ground). Bleed all 4 wheels from Passenger Rear, to Driver Rear, then Passenger Front and lastly Driver’s front. If no fluid pushes through.. you either have a bad/faulty Master cylinder or rubber hoses that have collapsed. Checking rear wheel cylinders for leaks is also a must.
Master cylinder.
Demonic
Well-Known Member
Booster and check valve should hold vacuum for 2 days or longer. See what it does tomorrow and go from there. KH 4 piston calipers do NOT like to sit for years at a time. I'll bet one out of fore is sticking. But there's more trouble than that.
Professor Fate
Push the button, Max...
Start narrowing it down, little by little. Does the pedal feel firm, or go to the floor when you step on it? Crack open each bleeder and have a buddy step on the pedal. Got fluid pressure? Probably your calipers/rear cylinders. No pressure? Crack your brake line fittings where they connect to your hoses. Got pressure there? You've got bad hoses. No pressure? Go to your distribution block/proportioning valve. Crack each line going out of the block. Got pressure? Then there's blockage in the line(s) going to your wheels. No pressure? Crack the lines going into the block. Got pressure now? You've got a bad distribution block/proportioning valve. No pressure? Crack the line fitting(s) coming out of your master cylinder. Got pressure? Bad line(s) from master to dist. block. No pressure? Bad master. That's everything. Oh yeah, keep your master cyl. full while doing this.
When I step on the pedal it is hard as a rock. Start the car and nothing changes. I would think if a caliper or wheel cylinder was stuck there would still be pedal movement. There is vacuum at the booster. It’s like the piston is frozen in the master. I just want to know the best route to start so I don’t break a bunch of lines. I will try professors recommendation with a few modifications.
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