brake leak

[rancheeto]

i recently did the aspire brake swap on the s&h car, and now my master cylinder is leaking. i had another one off a parts car, and swaped it. the next day i came out and had no brake fluid in it. both of them were leaking from the same spot, right where the master cylinder meets the booster. does any one kno what would cause this, or how i could fix it?

thanks in advance,
Ryan

[rancheeto]

does any one know if the aspire master cylinder is the same?

[elcamino1]

Aspire will fit but you will have to move the front line from side to top,real easy I've done It!

[rancheeto]

is it any better?

[elcamino1]

It works the same as the one that came off!

[FestYboy]

it's your seals, they just need replaced. only problem is, no one stocks rebuild kits.

[rancheeto]

yeah, i found that out, but it was two seperate master cylinders, so i was just wondering before i bought another one if it could have been something else.

[festivaWES]

I've got 3 boosters/MC lying around if you need one.

[rancheeto]

I've got 3 boosters/MC lying around if you need one.

are the seals good?

[ejp2fast]

i didn't want to start a new thread, so i'll continue on this one...

i just bled all 4 corners and NOW i am leaking where the Master cylinder goes into the booster.... ??? why all of a sudden now? I wasn't leaking before I did the brake bleed, so did i pop this seal? anybody who has had this MC off, can this seal be made and what material is it? or is a new MC what i need?

[freshtiva]

A new master cyclinder w/o the reservoir is about $40. There are a couple of seals in the master cyclinder. I guess if you are going to have to replace the M/C anyway it couldnt hurt to take the old one apart and look at the seals first. Maybe you got some dirt or rust in the system. Try cleaning the seals and parts with denatured alcohol if they look OK otherwise.

[jglutz]

That's not un common....when you remove aire from the system the hydarulic pressure increases and something else blows. Typically....after some time...a little fluid will leak between the MC and the booster...the iron will rust and eventually the iron will pit or the rust will break loose and damage the seal

A couple years ago I was driving a GMC-6500 Dumper when the brakes failed. The MC cover rusted on the inside and the scale destroyed the MC. After I replaced the MC and bleed the brakes...one of the lines blew a pin hole. I ended up making all new break lines.

[Mike McKown]

Master cylinders sometimes leak after using the pedal push method to bleed brakes. This is because you're stroking the cylinder piston inside the bore to a depth it hasn't been running in and that bore depth is sometimes filled with rust, scale and other contaminants. These things will get on the seal and eat it up or otherwise cause it to lose lip contact with the cylinder bore.

If it was mine, I'd take it apart and clean it with the intention of putting it back on the car afterwards. Sometimes it works, sometimes it doesn't. I wouldn't tell you to do this because you may make an error in judgement and the results may not be good.

If I knew the master cylinder was an original, I wouldn't screw with cleaning it and trying to make it work, I'd go get a new one.

[jglutz]

^^That's a good comment.
Even if you could by a rebuild kit...I haven't seen small bore hones for sale in a long time.

[hawkdoc60]

That's not un common....when you remove aire from the system the hydarulic pressure increases and something else blows. Typically....after some time...a little fluid will leak between the MC and the booster...the iron will rust and eventually the iron will pit or the rust will break loose and damage the seal

A couple years ago I was driving a GMC-6500 Dumper when the brakes failed. The MC cover rusted on the inside and the scale destroyed the MC. After I replaced the MC and bleed the brakes...one of the lines blew a pin hole. I ended up making all new break lines.

That is exactly what happened with the Festiva I was working on for the guy last weekend.