Loosing Brake Fluid

[dagwoodzz]

 

I've been losing break fluid over the last month and heard a hissing noise this weekend. ran my fingers under the reservoir and could feel the leak. My question is this. is there a gasket between the reservoir and the master cylinder that will repair the leak, or does everything need to be replace.

 

I am a poor mechanic and some need some help on names. I know what the reservoir is, but I dont know what the piece is called that the reservoir sits on. I believe the master cylinder is behind the black boot on the right. If someone has the time to explain how the leg bone attaches to the thigh bone and what the correct names, I'd appreciate the lesson.

 

Thanks, Dag

Edited June 18, 2007 by dagwoodzz

[GhostPath]

The gray thing the brake fluid reservoir is sitting on *is* the brake master cylinder. The big black drum on the firewall that it is attached to is your vacuum-assist power brake booster (also known as the brake servo).

 

It sounds like you have a bad master cylinder and a bad booster.

 

I don't know what year model you have, but the Nissan FAST system says that there's no gasket between the master cylinder and the booster on the WD21. However, there is a gasket, a spacer, and another gasket between the booster and the firewall/pedalbox.

[dagwoodzz]

Thanks, it had to be a stupid question, but it was just in my head the master cylinder wasn't that small.

 

I'm going to try to get thru the week just adding brake fluid if I can. Sounds like another fun w/end under the hood.

[GhostPath]

Um... That car isn't safe to drive. At the very least, replace the master cylinder to stop that leak leaking - not least of which because your engine is sucking in that wonderfully corrosive brake fluid.

 

Leaking master cylinders are time bombs waiting to happen - guess what happens if that leaky seal in the master cylinder gets worse? You'll lose the primary braking circuit, and you could blow that seal out at any time with any application of the brakes - which means you could kill someone. If you get in an accident because you couldn't stop, you could be charged with criminal negligence. Fix the car or park it, because taking that chance isn't worth it.

[dagwoodzz]

Done, parked.

[mws]

Bummer. 2 issues at once.

Leaky fluid = bad MC seal

Air hiss = booster leak

[GhostPath]

Good. Brakes are the one thing that nobody should ever take even the smallest chance on. If your engine dies, the worst that happens is that you have to coast to a stop. If your brakes die, quite often so does someone - either the operator or whatever you hit.

[bryfry]

Unfortunately, the leaking rear seal on the master cylinder probably caused your booster to fail. Brake fluid is highly corrosive (get it on your paint and see what happens!!), like GhostPath said, so it probably ate the diaphragm inside the booster.

Ouch........that's gunna cost ya'.

[dagwoodzz]

$236 and change for crappy rebuilts. When the core chare is refunded, it will be less than $200. I can't justify paying for new parts on a 20yr old ride.

 

Starter was $100 last week, still need to replace plugs, wires, distributor. It's almost equal to my wife's monthy car note.

 

Otherwise it's been running w/ no problems for almost a year now. You can only ride for free for so long.

[dagwoodzz]

not least of which because your engine is sucking in that wonderfully corrosive brake fluid.

 

You weren't kidding about the corrosive brake fluid. Under the reservoir the fender well was bare metal. I primed it while everything was out, but dripped quite a bit installing the master cylinder. Sprayed it down at the carwash this morning, but the fresh paint is probably gone already.