I was having a discussion with an older guy at work, and was mentioning that when I first get in the car, I usually push the brake pedal in, and let it out to get it 'pumped up', so that if I need to stop suddenly while I am driving, I don't have to worry about the pedal dropping to the floor.
He seemed to be convinced that there was some sort of problem with my brake system, although I have changed all four brake cylinders and the master cylinder. None of the brake lines leak, and I have had no problem with brake power. They will lock up easily if I slam on them, but that is true of every car without ABS.
Is he on crack? (he is kind of a weirdo) Or does it sound like I maybe got a defective master cylinder? I constantly have discussions of this sort with this guy, and he usually comes off as a crackpot.
Manual Brakes - Pumping?
If your pedal drops to the floor sometimes and sometimes does not - it's not right. If you don't have leaks, and your hoses are fine, then your master cylinder definitely needs attention.
Manual Brakes - Pumping?
Like I said, it doesn't seem to have any problems after that first pump.
I had another guy at work suggest that it might have something to do with the proportional valve, which is the only original part still in the car.
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On any car equipped with MANUAL brakes, the pedal will pump up some. This is normal as long as the pedal height stays relatively close to the %26quot;pumped up%26quot; height.
If your brake shoes are out of adjustment, you can have a low pedal with no hydraulic problems. A %26quot;Rule of Thumb%26quot; is for the pedal to be even with the accelerator pedal or slightly above it.
There are circumstances where drum diameter and brake adjustment may cause variance in pedal height. If the fluid is not going down in the master cylinder then it is probably adjustment. If you need to add fluid you have a leak. I have come across bad rebuilds on master cylinders. No leaks found, brakes adjusted correctly, drum diameter within specifications, vacuum bled the hydraulics, emergency brake adjusted correctly, brake HOSES in good condition, and still had the pedal travel BELOW the accelerator pedal. I found that the master cylinder bore allowed fluid to go between the primary and secondary piston cups. %26quot;PEDAL MUST BE EVEN OR ABOVE GAS PEDAL%26quot;.
If your brake pedal does indeed drop to the floor, perhaps your masster cylinder or wheel drums need attention. I have noticed evenon my '91 mustang that it is possible to %26quot;pump them up%26quot; slightely, but i think this is normal. I think that it is pretty normal, but it probably won't drop to the floor. Pumping them before driving can't hurt.
You should not have to pump up your brakes, that is a clear sign that you have air in your system. Do a real good brake bleed, including the new master cylinder and you won't have to pump anymore. I learned a long time ago, when an old guy tells you something like this, it is well worth considering.
It sounds like you definately have air in your lines somewhere. Try bleeding your brakes starting with the wheel furthest away from the master cylinder and work your way to the front driver's side. If you have new wheel cylinders, you shouldn't have any problem with the bleeders busting off. Have a partner get in the drivers seat and pump the pedal until stiff and keep foot pressure on it while you crack open a bleeder. Let the fluid squirt out while your partner is letting the pedal go to the floor. Keep pedal to the floor until you tighten the bleeder. Yell up there and tell him (her) to pump it up again. Do that to every wheel and see if you can keep a stiff pedal after finished.
If this fails, you have a leak somewhere...more than likely it is like what you mentioned in your question....a faulty master cylinder or maybe even one of those new wheel cylinders was bad. No, your friend isn't a crack-pot...he makes sense. He is probably just a little weird haha
