My brakes have been feeling really bad recently. I have bled the brakes a few times using ATE fluid, new calipers, pads, rotors etc.

I have not removed the master cylinder though to bleed that.

The brake pedal feels terrible, I have to push the brake in really hard for it to shop and feels like it does not do a good job. After maybe 5-10 hard brakes they start to feel better and seem like the pedal works better.


Sometimes it does feel like it pulls more to one side when I brake which made me think seized caliper however I checked them and the pin slides freely and the piston can be compressed easily.

Anyways I do have another 2 front calipers I will be installing this spring, new rotors, new oem pads, new brake lines and new fluid but I would hate to do it all again and have the same issue.

Not sure how likely it is to have air inside the master cylinder and if that is not the issue how likely it has to do with the brake booster.

They seem to be quite cheap on ebay for a used good condition master cylinder and brake booster that I could swap in but would rather not if that is likely not the issue.

My car does have 193k miles on it now on original master cylinder, brake lines, brake booster etc.


Just do the master cylinder but leave stock brake booster?

 

If you pump the pedal does it build pressure?

 

Yes it does.

 

Possibly master cylinder or ABS/ VSA modulator internal leak. Your description of it pulling makes me think modulator. What year is your car?

 

It's an 01 with 193k miles on it now.

 

For ensuring all of the air is out of your lines when bleeding, I have found this to be an absolutely indispensable tool: http://www.amazon.com/Motive-Product...+power+bleeder



You may have more going on with your car, but I have used that power bleeder so many times over the last 10 or so years, it has paid for itself 10x over!

 

I've thought of getting one of those. Do you have sealing issues? It seems many with this don't get a good deal around the BMC and have it spray out brake fluid.

it seems most or all were on cars where the cap didn't screw on though just a push on cap.

 

I'd probably start with a new MC. Double check all other brake components- calipers and pins to make sure nothing is frozen.

 

The one I have is just a rubber seal the presses against the top lip of the reservoir. You hold it on with a chain that slings around the bottom of the BMC with some adjustable hooks that you screw a wingnut on them to tighten it. Not the most elegant solution, but VERY adaptable to many different vehicles. You just have to check that you have a good seal before allowing the brake fluid to be picked up - hold the bottle sidways while pumping so only air is forced up the tube. If you hear a hiss, you need to adjust things. After a couple of uses, you'll get the hang of it and it's very easy to get setup.

Recently I came across a member that had a spare reservoir cap that he tapped a fitting into and used that instead. For S2000 specific use, that seems like an excellent idea, and one I intend to try sooner or later. Just need to get my hands on a spare cap.

 

ok cool. Yeah I just read that using some clamps seem to work better than the chain and j hooks. I also read that the stock cap won't seal well enough to handle the pressure inside.

I think I will give this a shot. Can't hurt at least and should help get any air out of the BMC if there is any in there. I may just buy a new one to be safe though.

Seems they are sold without the reservoir. Is anything else needed like seals or gaskets to install my reservoir onto a new BMC?