i know this isn't 100% auto-x related, but i cant auto-x with no brakes and i know i'll get an intelligent response from users of this forum.

here is the situation:
i have a 92 si with 4 wheel disc. the car has always had weak brakes...really squishy and pedal would go to the floor on occasion. before we started my swap we went ahead and fully flushed and bled the brakes. this is when the trouble started. after bleeding the brakes, the pedal feel was worse!! with the engine off and pumping the brakes, it took a lot of pumps for the presure to build on the pedal. when the car is powered on the pedal goes right to the floor with no effort. we kept bleeding and bleeding the brakes...every time we would go around and have nice, bubble free pumps. go around another time and the first pump would consistently give a trickle of bubbles on the first pump. we did this so many times we wound up blowing the M/C seal. replaced that and hoped it would be good. we swapped the motor on the car and our foucs went back to fixing the brakes. after bleeding them again we ran into the same problem. i went out and got a new M/C and bench bled it and installed it. went around and bled the brakes again and still, same problem. we will open and close the bleeder on a wheel and it will give a good pedal feel, but as soon as we go around again after finishing all of them, we'll still get a trickle on the first pump. we've gone through at least 8 big bottles of brake fluid in this process. there are no fluid leaks anywhere. its always the same...it will seem to build up a little bit of pressue with motor off, but as soon as its started, pedal goes straight to the floor. this issue has stumped about 4 of us!! anyone have any ideas? we're thinking it might be the booster but that would make the pedal harder to push, not easier, right? can anyone think of anything else to try? do i just have rediculous amounts of air in the system? with all the fluid we've gone through, i'd hope not. we've run through the tests in the helmes and nothing helps. please help! i cant even break in my new motor cuz my car has been stuck in the garage for the last two weeks!!

thanks!


[Modified by FnkyChnkyMnky, 6:41 AM 10/11/2002]

 

Brake lines OK? (No runs, drips, errors?) No bulges in the lines?

Brake pads OK? (no bent plates, no glazed material?)

Possibly bad bleed screw? Try some Speedbleeders. Some here don't like them, I think their a must-have for a racer.

Jsut some thoughts. I'm sure others will chime in.

Edit: what kind of fluid are you using?


[Modified by MaddMatt, 5:42 AM 10/11/2002]

 

i suggested possible leaks in the brake lines as well but they seem fine.. we haven't found a leak yet. we haven't checked for bulges yet.. we'll give that a shot. we haven't checked the pads either but i don't see how a glazed set of pads would make the pedal drop to the floor, they'd just make for terrible braking power while being driven. we thought about the bad bleed screw as well so he picked up a set of speedbleeders.. unfortunately he grabbed the wrong size for the rear (drums opposed to disks). he'll be getting the correct ones today but we went ahead and bled it AGAIN last night with the new speedbleeders on the front and got the exact same thing.. decent pressure before the booster got vacuum but once the car was started the pedal dropped straight to the floor. we're using valvoline dot 3 (pyroil) fluid..

c'mon guys, i know you've worked on your brakes more than anyone else on honda-tech, that's why we're posting here.. heeeeeelp..

i want to add that before we even start the car the pedal doesn't feel right either. it has this weird squish to it.. it'll compress about a quarter of the way before getting solid.. and no it's not just excessive brake pedal travel, you can feel a slight resistance when pushing it before it gets stiff.. i'm baffled..


[Modified by bojangs, 7:08 PM 10/11/2002]

 

That MC is used right? Might be that.

But I suggest to bleed it more... then keep bleeding! Tap on the calipers with a rubber mallet from time to time while bleeding.

Bleed it today, then tomorrow, then again!!!!

Get my point? When bleeding after a line swap, or full conversion, its going to take alot to get all the air out.

 

we've bled and bled and bled, and we'll continue to bleed and bleed and bleed! its just that even after all this bleeding, we dont ever see any improvment... we would think that as we slowly start working more and more air out, the pedal feel would improve over time...


[Modified by FnkyChnkyMnky, 6:27 PM 10/11/2002]

 

so that's it huh? check for bulges and keep bleeding? no one has any other ideas??

 

ttt <--- cries of a desperate man!

 

Couple of thoughts:
Double check your bleeding procedure - make sure you are not going letting air back in. Speedbleeders or a pressure bleeder could help here.

- When you get a few bubbles in the line it could just be air trapped in the bleeder screw and not actually air in the lines.

- Don't just bleed one corner for 10 minutes. Do short bleeds (30 seconds) and keep rotating around the car - you are trying to move air through all the lines, distribution blocks, etc.

- If you swapped the MC and did not bench bleed it, you are in for a world of bleeding. it takes a phenominal amunt of bleeding to get all of the air out.

- An old mechanics trick to determine if a particular wheel is use a pair of padded vice grips to clamp shut the rubber line leading to that wheel. That way you know if that wheel is causing the problem. Be careful not to damage the line.

- My guess is bleeding technique / tools or air from the MC swap.

-Phillip

 

can you explain this a little more? im still unclear when you clamp the line and what you do after that.

thanks

 

ttt

 

this happened to me when I switched out to bigger brakes in the front:

When we swapped them over, the brake pedal went to the ground each tim I pumped. We bled the brakes...but nothing was working. We kept bleeding and bleeding and bleeding and we wound up with the same result.

One of us go the bright idea to take caliper off and put the bleeding nipple thing straight up into the air. That would force any air in the chamber to be forced out..

Get what I'm saying?

 

hers the troubleshooting test.

http://24.169.49.89:7080/manual/2gsm...s/91-19-16.jpg