Weird Brake problem

Throw away the master cyl. Internal seals of master are leaking and yes they can intermintently leak. Sometimes you can slowly and smoothly depress the pedal and push the pedal to the floor. Then push down with force quickly and the pedal will hold.
Phil

Dammit! I will pull back the boot to see if it is  leaking from there. That is where it would be leaking from right? Where the rod goes into the piston? It is a new MC too :(.

Edited by jscheiner.09 - 07 Mar. 2017 at 2:11pm

If it was a leak where the brake fluid got past the piston into the rubber boot would that be considered an internal leak?

Internal seals will bypass fluid sometimes, meaning as you press down on the pedal the fluid will go around the seal instead of the seal pushing the fluid forward towards the wheel cyls, this will not cause an external leak. there is also sealing at the back of the master to keep fluid from escaping at the plunger side of the master, that would be an external leak. If you saw fluid on the ground under the master, there has to be residual left. brake fluid will not evaporate or at least not for some time. Try wiping your finger in the boot and any where the system seals and see if there is wetness on your finger. Clean brake fluid is sometimes hard to see(at least for my eyes) Seals in the master is the only thing I know that would cause the pedal to go to the floor one time and not the next yet show no external leakagePhil 

Its possible they overfilled the reservoir and with using the brakes the fluid expanded leaking out the top. Does the cap seal well. Did the last shop replace the master along with other brake work. I think I would take it back to them to remedy you issues seeing as they had there hands on it last. Maybe some one else wants to comment, but it sounds unsafe to me.

Is the heat shield between exhaust pipe and M/C in place? 

Is there a reason that you do not want to take it back to the mechanic that "fixed" your brake fluid leak? Did they take too long? Did it cost too much? Are you embarrassed? You should not be embarrassed, the mechanic should, & they should fix it free. The leak is why you took it to them. It should not leak. Take it back for warranty work.

Now the pedal going to the floor without getting any braking action may not be the mechanics fault. It is probably a separate issue. It does sound like a master cylinder issue from what I am hearing. Your old cylinder may be rebuildable. Yet, it may be cheaper to buy a new one. Check that out. Done right a rebuild is as good as a new one, plus the old one will fit in the rig without any modifications. The new one should, but as we all know, there are a lot of "should"s in the world.

If you get a new one, try not to get a Chinese or Indian one. They "should" be able to make a correct part, sadly, that does not seem to be the case.

IHTH, Cpt Logger.

jscheiner.09 wrote: I actually spoke to them about it... I wasn't sure if I should take it back because it is something that was different from what they fixed being that it was the plunger. I just assumed it was a faulty MC. So I should most likely just take it back to them and let them fix it ? Js

Yep, they should have tested it before they sent it out the door. Take it back and have them fix it under warranty.
Where did you get the MC?

Yeah I definitely agree....
I am going to call up the mechanic and take it back to have them check it out. I could easily just replace the master cylinder myself for 60 bucks. Hopefully if I take it to the mechanic they don't charge me more than that.... as in I hope they wArranty it.
I got the master cylinder from Kaiser Willys and put less than one mile on it.
Maybe I should call them and see if they can take it back.

Thanks for all the help guys !