With the engine idling and the car at a stop, can you bottom out the brake pedal?

I can with a little effort, and I just don't know if that's right or not. The pedal doesn't sink gradually as would be indicative of a bad MC. And I haven't lost braking effectiveness at all. I can still lock them up as easily as when I got the car. And they engage at about the same position they always have. There's no mushiness or "pumping up" to indicate air in the lines.

I guess I just never noticed that I could bottom out the pedal before. Also when the engine off, the pedal is hard as a rock (after I pump out the vacuum assist). It doesn't sink, and there's no way in hell I'd be able to push it to the floor then.

 

Someone must have tried this. Jump in your car and check!

 

at idle, I cannot push the brake all the way to the floor.

 

hmmm ... maybe I'd better try bleeding them again. I bled them a few days ago, and that's what led into my curiosity. I also didn't follow the X-pattern bleed order. I just went from farthest to shortest. I've been poking around, and it appears I should have gone pass-rear, driver-front, driver-rear, pass-front.

And someone also mentioned about being careful not to bottom out the pedal while bleeding? ...not sure why that would matter though

 

If you do the wrong order, I think the only problem is you have to go around a couple of 'laps' before all the bubbles are gone. So just try it again.

The bottom 1/3 or so of the pedal travel NEVER gets used. So there's probably crud & the cylinder walls aren't polished by frequent use. So when you push the MC pistons thru that area, you maybe(?) tear up the seals. That might lead to the classic sinking pedal of a bad MC. Since you don't get the sinking pedal, I guess that didn't happen?

I've always pumped mine all the way down, before I heard about this issue. I never had trouble, but I quit going all the way down anyway.

 

Yeah I'm pretty sure the MC is fine. I know it's not internally bypassing at least. I might just replace it for peace of mind anyway though. It's probably original and hence has 145,000 mi. on it.

I'll try bleeding in the correct order tonight and see if it makes any difference.

Thanks guys!

 

Damn, no change .. I just re-bled in the right order, and it's the same thing. On second thought, maybe the MC is bad. I did the press and hold test on it, but I couldn't tell if it was actually sinking or if I was just gradually applying more pressure. If it is bypassing, then it's doing it very slowly. But regardless, it's probably on its way out. *sigh* ...guess what I get to do tomorrow night!

gurgle = me btw (forgot password one day)


Modified by wcsinx at 1:39 AM 11/9/2004