Did I blow my master cylinder

Long story short, I lost my brake fluid while driving last week. I was near my house, and did not have any issues other than the fact that my pedal went to the floor and my braking distance was compromised.

I know pushing the pedal to the floor without fluid in the system is a no-no because it can damage the master cylinder. The car is now in my garage on jackstands. What should I do? Can I simply add fluid and bleed it? Should I check to make sure the master cylinder did not blow? If so, how do I do this?

This is on an E30 by the way. Thanks for your help.

Bleed the lines. You'll notice if it is blown. You just want that air out of the lines. What more damage do you expect to do?

(don't do this befor someone else says to. Not an expert.)

Im not really sure what other damage is possible, I guess thats why I am asking. I will try bleeding the lines. If I blew the master cylinder or the seal, it simply wont bleed properly?

Sounds about right. I assume you don't know what caused the loss of fluid? Check for busted lines, cracked lines, premature leakage, and all the obvious. Something made that fluid go bye-bye.

In reply to N Sperlo:

I know where the fluid came from, but I havent had time to diagnose how or why it puked itself out. It may have simply been that the line was loose. I will of course do the diagnosis before/when I bleed the brakes.

Thanks for your help Sperlo.

Good luck. My advice has a five minute warrant, so hurry up.

I"m not sure if modern master cylinders will suffer damage from traveling the full length of the bore. Not sure, but I think you're clear on that one. If it was a line or hose, replace them all. The others are not far behind.

I don't know whether newer master cylinders would be any more resistant to pitting in the usually-unused part of the bore than older ones, or whether newer seals would be more resistant to damage from such an incident.

I'd be inclined to like DrBoost says, but keep it in mind; if the pedal drifts downward, or anything else wacky, the master cylinder would be my first suspect once the first issue is rectified.

EDIT: Pretty sure an E30 M/C is old enough to be susceptible to such damage, but that's not to say it has to have happened.

It can be tough to get a master bled in the car if you've run it dry. Pull it out and do a bench bleed. That will let you test to see if it's "blown" and also ensure you're not blaming a good master for a bleeding problem.

MC bleeding lines are amazing things to have, though I can't think of a place to get them off the top of my head.
you'll have to figure out the thread pitch and size of the lines, and they are just basically hoses that are threaded on one end and just open on the other
put the MC in a vise, block the holes where the lines go, fill it. wont hurt to replace the seal &lube on the piston while it's already out of the booster.
pop whatever you used to plug the holes out and quickly screw the bleeder lines in, with the open ends circulating back into the top of the mc.
push the piston in ALOT and then reinstall it, making sure not to spill all the fluid out when you swap the bleeder lines for the real lines. won't hurt to do a quick bleeding at the wheels too.

^^what he said, plus
Take a look inside the booster. If there is any fluid inside, or on the outside of the booster, under the MC, you'll want to rebuild or replace the MC. Fluid can leak out of the rear seal and into the booster. This will degrade the rubber diaphram and leave you with un-boosed brakes.

ransom wrote: I don't know whether newer master cylinders would be any more resistant to pitting in the usually-unused part of the bore than older ones, or whether newer seals would be more resistant to damage from such an incident.

personal opinion based on my personal experience: an aluminum MC bore is less susceptible to this type of damage than an old-school cast iron MC. i'd refill it, find/fix the leak, gravity-bleed the system, then give it the stomp test a bunch of times, then give it the press-and-hold test. if pedal doesn't creep to floor, i'd think that it's OK.

In reply to AngryCorvair:

I appreciate all the advice, I think that Im going to try the old gravity bleed first, and then if that doesnt work pull the MC out. As of now there is no fluid leaking, the fluid problem was at a connection in the brake line at the passenger rear.