sinking brake pedal...
 

I was driving today and I noticed that at a stop if I kept my foot on the brake with some resistance, it would slowly sink down toward the floor. It would never actually hit the floor completely but this is definitely a new problem nonetheless. What could be causing this issue? Is my master cylinder on the way out, or could it be something else?

how are your fluid levels?

one time I failed to tighten down one of the connections between the hose and caliper and I had that problem. Look around your brakes for a wet spot.

fluid levels look ok. no leaks that i have noticed so far.

Sounds like either the master cyl or brake booster (or the check valve on the brake booster). Never had to buy either for a Honda, but for other cars you can get a master cyl/booster combo for not too much.

Most times it's the master cyl. The fluid under pressure leaks past the seals to the unpressurized side and back to the resevior. Since the leak is internal you won't see a loss of fluid or any wet spots. I bring up the booster since I've seen them do some really funky stuff.

FWIW, I've seen the sinking pedal problem go on for years and just be an annoyance, YMMV.

brake master cylinder, $50 at autozone.

yeah a had a accord had the same problem ended up replacing both master cylinders and boosters in the rear

the same thing happened in my Integra, that's why I know the price :p

replace it ASAP before you can't stop anymore... I almost hist someone if it wasn't for the hill slowing me down :sad:
oh and pump your brakes, nvm you have ABS

my accord has done that for years. never been an issue. i've even heard of some new hondas doing that. aparently, it's normal. very alarming at first, but apparently not a problem...? at least according to the techs i've talked to...

well, i've noticed that it only sinks when i push down on the pedal with a good amount of force after I have already come to a stop. So I don't think it's going to be a major issue, at least not for a while. :oh:

same here. in the summer it will get worse with the a/c on.

good thing my a/c doesn't work right now. ;)

Try flushing out your brake lines, so you have all new fluid, and then re-bleed

My Teg did the same thing until I changed the brake MC. Replace that and it won't happen again, unless the booster isnt holding pressure but thats very unlikely.

Edit: oops I ment it WONT happen :doh:

i'm probably gonna try that sometime this week.

so umm....the pedal was definitely giving me trouble today. It was nice and warm out and I had more instances of the pedal sinking than usual. What is the likelyhood that it could be the brake booster? I don't want to buy a ne MC only to find out that it was the brake booster to blame.

it is the MC, the same thing happened to me. Got a new one and it was all good.

if the booster was failing, you would feel LESS brake assist, not MORE. the pedal would be harder to push. so it's most likely the m/c, not the booster.

copy that! thanks. ;)

ok to buy a remanufactured mc from say, napa? I can get one for $78 + tax.

I bought a remanufacured one from Autozone, they give warrentys on remanufactured parts.

I'm glad this came up. The last time I drove my 95 GSR, I was stopped in LA traffic going uphill and my brake pedal sunk all the way down and my car was about to slowly start rolling backwards; I exited and took the streets home. Great info everyone... now I believe my brake MC may need to be replaced.

yeah, if you're gonna crash your gsr, slam it into a pole like i did. don't just roll back into someone, that's weak. seriously tho, glad you got the chance to solve your problem before it became a bigger problem!

Does NAPA not offer warranties on reman. parts? I forgot to ask...:oh:

Yes, napa typically has a 1yr warranty, keep your reciept handy.

If they offer you a choice between a 1yr warranty part and a lifetime warranty part, get the lifetime part.

From my experience the 1yr parts are crap. I once went through 4 alternators in a year. On the last one, I paid the difference between the 1yr and lifetime part and put the lifetime alt in. That one was still in there when I sold the car 3yrs later.