johnking3194

Ok so I had my brakes powdercoated then rebuilt them myself with my friend(a mechanic). I installed goodridge braided brakes lines as well. I orginally bleed them myself only to find what seemed to be air in the abs system... I had the stealership use a tech 2 to bleed the abs system and it seemed to by kinda fixed.. when ever i hit the brakes it makes a hissing sound around the brake pedal and now if i dont pump the brakes the pedal goes to the floor and has no stopping power what so ever. Whats really strangle is that when my car is off my pedal will not go to the floor and is actually extremely stiff. But the secont the car has power the pedal goes straight to the floor and I have to pump the brakes in order to stop. It has slowly but surely gotten worse!! Someone please help cause i have absolutely no clue what is wrong.

heavymetals

iTrader: (3)

That is why it is called "power assisted".

Only works when there is power.

Sounds like your master took a crap.

NoChrome

iTrader: (3)

Ok, your brake booster is a diaphragm, engine vacuum pulls both sides, you press the pedal and a valve opens allowing ambient air to the cabin side of the diaphragm, assisting you to force the pedal to the floor.

If the pedal goes to the floor under power assist either break fluid is slipping past the piston in the master cylinder, you have a leak somewhere or there is still air in system.

If i was betting, you still have air in there. I would rebleed the brakes a few more times, and go from there. If you poped the calipers off rebuilt them and put them back together, assuming you didnt mess something up in the rebuild process, there is no reason to suspect the master cylinder.

itsslow98

iTrader: (18)

Bleed the living crap out of the brakes.

johnking3194

Does it matter which piston on the brakes is on top? because the piston size varies and i have the bigger pistons on the bottom and the smaller pistons on top

Also the other day i hit the bakes and heard popping noise in the front passenger caliper what could that have been im about to take them apart and rebuild them

And do you think the goodridge brakelines have anything to do with it because if i can recall correctly other people have had the same similar problem as me when they switch to these brake lines

NoChrome

iTrader: (3)

As long as the brake lines are not flexing and expanding when you hit the brakes it won't matter. As far as which piston goes where, I have no clue. If you want to check to see if you have a caliper that's not engaging properly, draw a line across each rotor (outside edge to center) then get the car moving and hit the brakes, if you got one that's taking the mark off slower than the others start there with your bleeding, or potential rebuilding.

Sweetwilliebrownjr

Hissing is generally a bad booster. Going to the floor is prolly just air.

johnking3194

Soo because it is hissing on the way to the floor is just air? Why would I do that now but not do that before I rebuilt them? I'm just confused aide I've been brakes before and never had trouble and now I can't seem to figure out what's wrong

johnking3194

Well when I bleed the brakes with the car off to the point where there is no air bubbles but when I turn the car on hit the brakes turn it back off and rebleed them there is air bubbles in the system again??

Sweetwilliebrownjr

Hissing around the brake pedal is usually a brake booster leak. It leaks vacuum and you can hear it near the pedal. I'd say take it to a shop and have them look at it, and if there's no leak anywhere, power bleed it. The abs unit can also bypass and make it seem like the master cylinder is bad. The master cylinder could also be bypassing and sucking air into the system. Usually you can see bubbles in the master cylinder reservoir when you push the pedal. There are a lot of possibilities. Sounds like more than one problem, and your description may be interpreted wrong by the reader. Online diagnosing is scary, and brakes are a dangerous thing to play with. I like to stop more than I like to go!

NoChrome

iTrader: (3)

If the brakes are hard to press with the motor off, and easy to press with the motor on the brake booster is working exactaly the way it was designed. His brake booster is fine. He needs to rebleed the brakes.

Look there is alot of air in there, keep it up and it will get better.

heavymetals

iTrader: (3)

If you went to a dealer and they used TECHII to bleed the ABS, the procedure requires the whole system to be bled.

If they just exercised the ABS to try to dump any trapped air, that is not right.

You will probably need to bleed the whole system correctly and systematically, per the procedure.

9t8z28

iTrader: (19)

Are there (2) bleeder valves on each caliper? If there is only 1 bleeder, it must be positioned on the top, not the bottom.

RADEoN

iTrader: (12)

there's definitely air in the system. you probably let the master cylinder run bone dry when you were doing it.

FuzzyLog1c

iTrader: (4)

I had the dealership bleed my brakes per procedure, including Tech II purging of the ABS, to no avail. Once weather permits, I plan to remove and reinstall the entire brake line system, adding Teflon tape on all threads, and replace the master.

raven154

iTrader: (14)

All the brake line fittings should be a compression type fitting or banjo with crush washers. I don't see how Teflon would help if the lines are installed correctly and clean with new or annealed crush washers.

RADEoN

iTrader: (12)

Teflon wouldn't do much, if anything. The brake fluid would almost certainly eat away all the teflon in a quick instant.

FuzzyLog1c

iTrader: (4)

Well, in that case, I'll just check the torque on all fittings. The idea was based on the fact that I had to wrap the caliper bleeder screws with Teflon to properly bleed the calipers.

johnking3194

soo basically just keep bleed and rebleeding and if that doesn't help take it the the dealership and see if they can diagnose the problem better?

johnking3194

the whole system was bleed when they bleed the abs system.