Brake pedal has no pressure

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70DartMike

70DartMike

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So I recently did a disc swap from a 75 Dart (single piston callipers) onto my 70 Dart. The swap went fine, I bled the brakes, but while bleeding them I never really got any pressure in the brake pedal.
Ok so today, before starting the car, I pumped the brake pedal about 20 times and then the brake pedal was stiff like there was pressure, but then when I started the car, the brake pedal just went to the floor as if no brakes and no pressure or anything at all. Then turned the car off, and pumped the brakes a few times and got that pressure back, but then again when the car was running there was nothing. And I don't mean nothing like.. a little bit of pressure. Nothing as in the feeling you get when you have no brakes.
Also, I have power brakes, and when the car was running, if I would press the brake pedal, the car would idle a little higher when pushing the brake pedal in, does that have something to do with the vaccuum?
Could my callipers be seized? Would that explain why I could bleed the brakes but then not have any brake pressure?
 
70DartMike said:
So I recently did a disc swap from a 75 Dart (single piston callipers) onto my 70 Dart. The swap went fine, I bled the brakes, but while bleeding them I never really got any pressure in the brake pedal.
Ok so today, before starting the car, I pumped the brake pedal about 20 times and then the brake pedal was stiff like there was pressure, but then when I started the car, the brake pedal just went to the floor as if no brakes and no pressure or anything at all. Then turned the car off, and pumped the brakes a few times and got that pressure back, but then again when the car was running there was nothing. And I don't mean nothing like.. a little bit of pressure. Nothing as in the feeling you get when you have no brakes.
Also, I have power brakes, and when the car was running, if I would press the brake pedal, the car would idle a little higher when pushing the brake pedal in, does that have something to do with the vaccuum?
Could my callipers be seized? Would that explain why I could bleed the brakes but then not have any brake pressure?
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The rise in idle makes me think your booster has a slight leak in the large diaphram or the small inner boot. Sounds like you still have air in the front brakes. Jack the car up and have some one push on the brakes. See if they apply preasure to the calipers bty tring to turn a wheel.
 
make sure the bleeders are on the top. The calipers ets switched left and right often. The fluid line should enter bottom and bleeder lets air off the top. If the calipers are wrong you can set the out of their guides and upside down to bleed. Make sure you dont twist the lines when puting them back in place.
 
Is the rubber hose to booster collapsing under pressure?
I had this happen when I hit the brakes, the hose collapsed on itself.

Replaced the hose and all was fine.
 
RedFish said:
make sure the bleeders are on the top. The calipers ets switched left and right often. The fluid line should enter bottom and bleeder lets air off the top. If the calipers are wrong you can set the out of their guides and upside down to bleed. Make sure you dont twist the lines when puting them back in place.
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Hey that is a GREAT point, Wouldn't be the first time that has happened. and you will never get the air out with them on the bottom.
 
No, bleeders are on the top, fluid lines come in on the bottom.
I got someone to press the pedal with the car turned off, and I tried spinning the wheels. The front drivers side didn't spin, but the passenger side did, but I could hear the pads rubbing the rotor.
Someone else told me I should try bleeding them a few times in a row, then try driving slow and slam the pedal down to maybe get the piston to move, then drive home and try bleeding them a few more times to make sure there is no air or condensation. Does this sound correct?
 
70DartMike said:
No, bleeders are on the top, fluid lines come in on the bottom.
I got someone to press the pedal with the car turned off, and I tried spinning the wheels. The front drivers side didn't spin, but the passenger side did, but I could hear the pads rubbing the rotor.
Someone else told me I should try bleeding them a few times in a row, then try driving slow and slam the pedal down to maybe get the piston to move, then drive home and try bleeding them a few more times to make sure there is no air or condensation. Does this sound correct?
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No, if the piston is that stuck you should replace them. I still think you may have air in the system.
 
did you bech bleed master? also it sounds like you have alot of air in system. When you bleed the system did you start from the farthest point from the master? Try bleeding it again from farthest to closest. you would be surprised on the air you will get.
 
I did start from the back drums and then did the front discs, but I will try it again (later when someone is able to help). I have a feeling the fluid that came out of the lines for the rear drums was really just old fluid that was still in the lines..
 
Always do both sides, remand calipers may be better than rebuilding.
 
I did bleed both sides, but I will do them all again after replacing a few parts. By 'remand' do you mean I should just buy new callipers? Or new pistons? Or what?
 
Remanufactured Calipers are usually cheaper than buying new pistons and kits. You might want to check on the cost of a power bleeding system, they are prety reasonable now days and is the best weay to get all the air out of your system.
 
SGBARRACUDA said:
Remanufactured Calipers are usually cheaper than buying new pistons and kits. You might want to check on the cost of a power bleeding system, they are prety reasonable now days and is the best weay to get all the air out of your system.
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Yeah thats what I meant "replace both calipers with reman'd". Very few car owners have the tools and skills to properly rebuild a caliper or wheel cylinder.
 
It might worth getting rebuilt calipers thru Lordco. I did my front brakes a couple of weeks ago and bought two Fenco calipers. They were ~$20 each plus a $10 core charge. I think the piston rebuild kit was ~$15 so why bother with all the work when for $5 more you've got it all done and ready to mount?
 
Bench bleed the master, then bleed everything, using a quart or more. Make sure you havin't moved the pro valve.
 
H22A4 said:
It might worth getting rebuilt calipers thru Lordco. I did my front brakes a couple of weeks ago and bought two Fenco calipers. They were ~$20 each plus a $10 core charge. I think the piston rebuild kit was ~$15 so why bother with all the work when for $5 more you've got it all done and ready to mount?
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That's what I did earlier today. I went in to Lordco and asked about callipers, and they told me they would have 2 for me on Monday, being about $30 each (including the core charge). Then I'll bleed the whole system sometime next weekend.
 
I had the same problem, I had to pull the caliper and use a c clamp to hold the piston in. I did one side at a time. You'll find you have some air trapped in the top of the caliper. It's an easy fix. I used the single caliper off a 74 and hung them on the rear of the disc. The bleeder wasn't at the very top of the reservoir.
 
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