My brakes have no pressure like they need to bleed them,but after bleeding pedal still goes to the floor.Is this the master cylinder?Is there a way to check it b/c I would hate to buy a new one and stil have problems.
thanks
steve

Check all the wheel cylinders/calipers/lines,etc for fluid leakage first.If everythings nice & dry,check the master cyl.It could be leaking out of the back.Fluid will be present on the inside (or outside)of the firewall.
The master could also be bypassing internally as well,& you wont see fluid leakage.
Gotta have brakes! tongue.gif

I was also wondering if the booster could be bad and not master cylinder. I do not see any leaks but do see fluid behind master but am not shure if thats from me when I bleed them(spilled).So I guess my question is how can you test to see if its the master cylinder or the booster? Thanks for the help.

Originally posted by 10bolt:
I was also wondering if the booster could be bad and not master cylinder. I do not see any leaks but do see fluid behind master but am not shure if thats from me when I bleed them(spilled).So I guess my question is how can you test to see if its the master cylinder or the booster? Thanks for the help. If the booster was at fault, you would still have a good brake pedal, but the effort to depress it would be increased. In other words, you'd have a VERY hard pedal. If the pedal is going to the floor, first, as suggested, check ALL of your wheel cylinders and brake lines, rubber or otherwise, for leaks. Then, move on to your master cylinder. If in doubt, replace it! Don't forget to bench bleed the new one before installing.

Pull the master off & physically look at the back of it around the big snap ring,& also look to see if theres fluid just inside the booster.You can also stick your finger into the bottom of the masters reservoir & see if theres a bunch of black crap down there.If so,the master is prob junk.
graemlins/thumbsup.gif

I just purchased a new mc from Napa Auto parts and will swap it out tom. I also got a mc bleeding kit. Thanks for the help,
steve

If you don't have one invest in a MightyVac pump bleeder.Makes bleeding the brakes a breeze,reuses the fluid AND keeps it off the garage foor!! Mike

In the future if you want to isolate the problem just remove the lines from the mast cyl and screw in the correct plugs into the master cyl depress the brake pedal and if it goes to the floor still yet it could still have air in it or could be by-passing inside .

After the swap, it was better but I still think it is a little too soft. I bleed the brakes ,but will bleed again in a few days to let things brake in a little bit.