Okay, this problem has been driving me crazy.

2 days ago, I lost my front brakes AGAIN. This is the 3rd time in the last 2 months! It's only the fronts, not the rears (fixed those already... bad flare at body line to hose). No visible leaks anywhere near the hoses or calipers. Already replaced copper washers between banjo bolts, hoses, and calipers. Hoses not deteriorated or damaged. Driver's side hard line brand new stainless steel (bought, not formed and flared by me), passenger's off of the old car and was cleaned and looked over thoroughly before being installed (and worked just fine on the old car... would have been stainless but the line was bent wrong ).

I'm looking into replacing the hoses, banjo bolts, and calipers (have plenty of extra copper washers and will probably get more with the calipers like always) along with getting new pads. IDK how old the calipers are... If I used one off of the old car, it's over 10 years old, and IDK about the one that came off of this one (if I didn't use both calipers from the old car). And no, the bleeder screws don't leak.

Should I be looking into a master cylinder as well? I haven't pulled the master away from the booster yet to examine the end seal for any leaks, but I don't hear any liquid getting squished around inside the booster or see/smell anything in the vacuum hose, so I can't tell as of right now... I'll pull the M/C away from the booster as soon as I get a chance.

 

Are you loosing brake fluid?

 

Losing LOTS of brake fluid... It's like the M/C is full one day and I lose front brakes a couple days later because the front half of the system is empty.

Like I said, this has happened a couple times now. The brakes were fine from the time the system was assembled early last summer to about early November and then I replaced the copper washers on both front brake hoses after the first brake loss (because I reused old ones that were fine when installed). And it happened again a couple days ago. I still don't see any indication of fluid loss around the hose-to-caliper connections, so IDK where the issue is, but all I know is that it seems to happen all of a sudden. I don't see any indication of a leak in either hose (swapping out the starter AGAIN ). The brakes are hard like normal until the fluid disappears to wherever it's going.

I'm at a complete loss as to what's going on which is why I'm thinking of just replacing every single bit except the hard lines.

 

It could be being sucked into the motor via a bad diaphragm in the brake booster. Thru the vacuum hose that supplies vacuum to the booster. Worth checking out.

 

Well, I went last week and ordered up a new master cylinder, new front hoses, and new front pads from Rock Auto (man, I hate their shipping!). I put the new master in over the weekend (blasted thing is cast iron and not aluminum ) and found out that indeed the old master had been leaking out the back but I couldn't see it. Since I already have the parts and they look somewhat iffy anyways, I'm also going to replace both front hoses. I need to wait until the crappy weather subsides and also until I get another bottle of brake fluid before I can finish the job.

 

I heard of some of those master cylinders being cast iron. I really don't think it will work any different, just look different.

 

Reman calipers are like $13 each. No reason to NOT replace them while you're at it.

I'd return the MC and get the right one.

 

Already have 2 pairs of calipers (one came on the 88 which are still there and the other came off of the other car), so I'm not going to mess with getting new calipers ATM unless I'm 110% sure I need NEW ones.

I'm also going to get a rebuild kit for the GM master cylinder. The cast one is nasty looking in every sense of the word... Between being cast iron (which will rust eventually!), it's dull and rough, and the fact that the reservoir isn't made of the proper plastic, it's just nasty looking.