MasseyMan1089

The other day I was at the airport and I was backing up and I didnt have any brakes! They were very stiff, like no vacuum. I took the lines off and I had vacuum. After that, it worked fine. I got home and lifted the hood and I noticed some brake fluid running down the master cylinder and to the steering shaft. It is leaking on the fitting below the master cylinder. I looked today, and its almost as if its from the shaft under the resivoir of brake fluid. Do I need a new master cylinder? Or do I need to do something else? I hate to not have brakes sometime?

infidel

If it's leaking you need a new one. I've found it cheaper and more reliable to buy a new or rebuilt one rather than rebuilding it yourself.

MasseyMan1089

So do I need a new one? I think it is leaking under the resiviour. Someone told me to wait until it leaks out to the add marks, then buy a some gaskets and pop the tank off, put the gaskets on, then it shouldnt leak. I dont want to risk it. I think I'll get a new one. It doesnt look hard. How do I bleed them?

moparguy

Sometimes with our trucks, it's possible to exceed the vacuum pumps ability to keep up. Usually happens with low rpm, heavy brakeing situations. I've had it happen a couple of times while backing trailers around on a hill, if you can raise the rpm, and give it a second, then it's ok.

I don't know if you can buy the gasket/seal between the reservoir. If you want to mess with it, just suction out the old fluid and pry the plastic reservior off and check things out.

If I do good job of bleeding a new master cyl. out on the bench, I don't have to bleed the brakes.

Good luck.

RJR

BoostdCTD

If it is just the grommets the reservoir sets on, I'd imagine it wouldn't be any problem fixing it assuming you can find the part. I had to do this to one of my cars in the recent past, it was cake.

Not very long ago somebody on the forum bled the brakes but since they didnt' bench bleed their new master cylinder it was nearly impossible to get all the air out.

As MoparGuy stated, the vacuum supply can be depleted when running at low rpms like you do when backing up. You can either ignore it, get a bigger vacuum reservoir, or spend a lot of money in hopes of fixing it.

MasseyMan1089

OK. Well, I looked today, after driving it all day, and I dont see any fluid comming out. I brake cleaned it clean lastnight, so there was no old stuff on it. Today, no new was comming out anywhere. It is dry now. I dont know why its not leaking. I have good brakes and everything. I did some heavy breaking today, and gave it crap to see if it was going to leak, but it didnt. I guess I'll wait on the new cylinder now?