WHY DOES MY PEDAL GO TO THE FLOOR AND MY CAR BARELY STOP?

Vehicle: 2000 Civic Ex.

Recently Installed:
- GSR Front Knuckles (Used)
- GSR Front Rotors (New)
- GSR Front Calipers (Used)
- GSR Front Brake Pads (New)
- GSR Rear Trailing Arm Assembly (Used)
- GSR Rear Rotors (New)
- GSR Rear Calipers (Used)
- GSR Rear Brake Pads (New)
- GSR E-Brake Cables (Used)
- Russell Steel Braided Brake Lines (New)
- OEM EM1 Proportioning Valve (New)
- A1Cardone Remanufactured Civic Ex Brake Booster (New)
- A1Cardone Remanufactured 2000 ITR Brake Master Cylinder (New)
- BrakeBest D.O.T. 4 Brake Fluid

Note:
- Accomplished bench bleeding of the new master cylinder.
- Brakes were bled multiple times starting from the furthest caliper to the closest to the master cylinder.
- No bubbles in fluid or leak detected anywhere on the car.

I am a fairly decent mechanic, but this one has me pulling my hair out.

PLEASE PLEASE PLEASE help me figure out what is wrong!

**Update**

Excessive wear on the outer edge of the front rotors.
But wear on the rear rotors seems evenly distributed.

 

If your not loosing fluid then the only possibilities are air in the lines somewhere, or a bad master cylinder.

What happens if you pump the pedal rapidly?

 

Your brakes are diagonally connected so you don't go farthest to nearest.

Pass. rear
Dr. front
Dr. rear
Pass. front

 

Just bled the lines again. Still no air.

Pumping the brakes revs the engine higher when it's on, hardens the pedal when it's off.

 

**Update**

Noticed excessive wear on the outer edge of the front rotors.

Ideas?

 

Did you adjust the pushrod on the new MC when you installed it? If you don't have any air in the lines that is really the only obvious thing that pops into my mind. Or just a bad master cylinder out of the box, which is possible but unlikely. I would play around with the pushrod adjustment and see if you get anywhere. This sounds like a classic bad MC but since it's new I have a hard time condemning it. Have you tried bleeding at the MC with it fully installed?

 

I bled it while on the car with the kit that came with it. I did not adjust the pushrod on the booster because that's more of a fine tune adjustment I feel like. I can try next weekend to play around with it.

I am going to try to bleed the master cylinder again as well. This time by cracking open the lines one by one as someone presses on the pedal. Hopefully I just bled it wrong the first time and there a bit of air I wasn't able to let out.

 

I couldn't figure out similar problems on my civic, I swapped out the proportioning valve and it solved the problem. I had a clogged proportioning valve.

 

Did you adjust the pedal or the brake booster pushrod in any way?

Since you notice no external leaks, the leak is obviously internal, if this is the problem.

Make sure your brake pedal is engaging the booster pushrod and actually moving the piston in the master cylinder.

I'm assuming you did not hook up the proportioning valve wrong.

Does the pedal drop straight to the floor or does it drop with some resistance? (stopping force)

 

I replaced the brake booster, so I needed to remove the old fitting that bolts to the brake pedal and install it on the new booster. I tried to position it as closely to the old one as possible.

I will check the pushrod contact as soon as I can

I had the same idea, but it turns out that I installed it correctly

There IS stopping power until it gets firm at the bottom, but only enough to stop it from rolling around in the driveway, it seems like the back brakes are engaging before the front brakes are (?) which I understand seems like a prop valve issue, but it's a brand new prop valve from Honda (46210-S04-902) so I have a hard time believing it's defective.




I am going to re-bleed everything from start to finish. The master cylinder, and all the calipers in the order specified above. I have to wait until thursday to do it but I will update this thread with the results once I do.

If I can't solve this by saturday, then I am taking the car to a local Honda shop and having them take a look at it. I bet I will feel like a straight idiot when they tell me what's wrong.

 

That would explain a lot for me, except that the prop valve is brand new.

still... it's an interesting theory.

 

http://www.tegger.com/hondafaq/maste...djustment.html

this may explain a lot.

 

I took my compressor and tried to blow air in to each port of the prop valve, and the bad one had 2 clogged ports where air couldn't go in or out. The new one was fine for each port.

Do you have a leak in one of the lines? or maybe a bad wheel cylinder?