mxt_77

Disclaimer: this is for my '95 Accord EX sedan w/ 190K miles. Bone stock, except for the Acura CL front hub/rotor swap.

My brake pedal was feeling pretty soft, so I did a fluid flush & bleed over the weekend. Now, I have a "sometimes firm" pedal, and sometimes the pedal feels exactly the same way it did before the flush. Is this a sign of air remaining in the system, or is this a sign of worse things to come (like a bad master cylinder)? I haven't noticed any leaks/seepage around the master cylinder, but I haven't really looked that hard, either.

iam7head

sounds like you have air in the system, it's very common to have air after a flush even you did eveyrthing right. it just the way it is,that's why most of the experienced guy/or track guy bleed it again after couple days of driving.

what's the condition of the line? at 190k, it shouldn't be using the same rubber hose from honda

check the brake booster while you at it

mxt_77

I think I figured out my problem. It appears to have been my technique. I was doing a one-man fluid change and pumping the pedal to flush fluid through the system. Well, it seems that every time I pumped the pedal I was sucking air back into the system. I flushed a half-liter through one corner before I figured that one out.

Once I realized that was the problem, I went with the "gravity bleed" recommended in another thread (by Billman250, I think). That seemed to fix my problem. However, if it comes back, I'll come back and update this thread.


BTW... yes, I'm still using the stock brake lines from the factory. The only things that have been replaced on this car are wear items (rotors... which were just replaced at 185K miles, pads, belts) and fluids (oil, tranny, brake, etc). At 190K miles, I'm still on the stock clutch, even. It has a bit of chatter, but no slippage.

mxt_77

^ On second thought... it's not my brake bleeding technique.

I think I have a faulty master cylinder, and I think changing the brake fluid just made things worse (since it flushed out the gunk that was probably holding the seals together). If I push the pedal in slowly, it will go all the way to the floor. Sometimes when sitting at a light, the pedal will just continue to creep ever so slowly and I have to pump it to build pressure again. That made for a nerve-racking road trip this weekend (especially since parts of it were in the Hill Country near Austin). Guess I'll be heading to the dealer tomorrow for parts.

FF2Skip

Was it in fact the master cylinder? I had a very similar problem this weekend at the track. Lots of pad, very new fluid, and the system gets pressure bled by me(ended up redoing it after every session to see if it would help). I already replaced the front calipers early this year. I'm getting very low fluid flow out of both rear calipers.

Btw, sometimes brakes are good to have on the track.

mxt_77

Yes, it was my MC.

Keep in mind this was in a car that had ~195K miles on it at the time, and I have no idea when the brakes had been bled previously. Apparently, the "gunk" in the system was all that was holding the MC seals together. When I did a thorough flush, that gunk got flushed out, too. Afterwards, if I stomped the brake, I'd get decent pressure, but if I applied pressure slowly, the pedal would go all the way to the floor.

Replacing the MC resolved the issue. The telltale symptom is the "sinking pedal" under constant pressure.

FF2Skip

Thanks. I really haven't heard of too many S2000 MC's failing, but that doesn't mean they haven't. Appreciate the response.