Lid to brake reservoir leaks

[Mike Quillici]

About a year ago I replaced my master cylinder. Everything works fine except for the fact that the lid doesn't seal well, and fluid slowly drips out if the reservoir while I drive.

I have messed with it endlessly, and now I'm wondering if I can put a bead of silicon or something around the top of the reservoir to seal it off. the lid and gasket are in perfect shape and are not rotted or bent.

[cdowns]

NO SEALANT will work it will just contaminate your brake system

the one thing i always check is the top sealing machined surface of the master// it sometimes has some roughness from the machineing process a light touch with a file takes care of it// if not i'd try a new gasket and cover

[magwakeenercew2jh]

Originally Posted by Mike Quillici

About a year ago I replaced my master cylinder. Everything works fine except for the fact that the lid doesn't seal well, and fluid slowly drips out if the reservoir while I drive.

I have messed with it endlessly, and now I'm wondering if I can put a bead of silicon or something around the top of the reservoir to seal it off. the lid and gasket are in perfect shape and are not rotted or bent.

I just went thru this as a part of my build I call, "If It's Wet, It Leaks".

I thought the cap was lousy...although it was new. So I bought another. Fussed around with the two wire "clamps". Every time, I'd drive my 1/4 mile test track, two streams out of the front drizzling down on
the steering shaft. Took a small amount of fluid out...etc., etc.

The way I finally fixed it was by using two gaskets and putting RTV gasket maker in between them, away from the ribbed surface that mates with the top of the res. Then, I ran and ever-so-small amount around
the rim of the res. It looked like the "new" res. was "pocked"....I did pay close attention to the area in the front and back of the top that is slotted for the part of the gasket(s) that peek thru.

My paranoia was, of course, that some of the RTV gasket maker would get in to the res., then into the system and...well, you know. So, although I used the RTV all around the circumference of the rim of the res.,
I sloped it toward the outside. Let it set for only about five minutes. Clamped the top down with the now two mated gaskets (Oh, yeah, I used a razor blade to take the two "bumps" that are supposed to poke thru
the cap off of the bottom gasket so that the gaskets were a complete sandwich with no gaps) .

Left it...Really left it...over night. No more leaks.

YMMV. And, I won't attest to either long-term anti-leaking, or the system being compromised. I was pissed. And it's my mistake to make...So...she's not leaking.

[LockDoc]

-
I did what Cliff suggested. Sucked the fluid out of the bowls, stuffed rags in them and carefully touched the top rim up with a new flat file. You have to be very careful to keep it flat with the surface but it worked for me. Go over the whole inside with a small magnet when you are done to get any shavings.

LockDoc

[Mike Quillici]

Originally Posted by magwakeenercew2jh

I just went thru this as a part of my build I call, "If It's Wet, It Leaks".

I thought the cap was lousy...although it was new. So I bought another. Fussed around with the two wire "clamps". Every time, I'd drive my 1/4 mile test track, two streams out of the front drizzling down on
the steering shaft. Took a small amount of fluid out...etc., etc.

The way I finally fixed it was by using two gaskets and putting RTV gasket maker in between them, away from the ribbed surface that mates with the top of the res. Then, I ran and ever-so-small amount around
the rim of the res. It looked like the "new" res. was "pocked"....I did pay close attention to the area in the front and back of the top that is slotted for the part of the gasket(s) that peek thru.

My paranoia was, of course, that some of the RTV gasket maker would get in to the res., then into the system and...well, you know. So, although I used the RTV all around the circumference of the rim of the res.,
I sloped it toward the outside. Let it set for only about five minutes. Clamped the top down with the now two mated gaskets (Oh, yeah, I used a razor blade to take the two "bumps" that are supposed to poke thru
the cap off of the bottom gasket so that the gaskets were a complete sandwich with no gaps) .

Left it...Really left it...over night. No more leaks.

YMMV. And, I won't attest to either long-term anti-leaking, or the system being compromised. I was pissed. And it's my mistake to make...So...she's not leaking.

Got it. . .i'm thinking of maybe trying to stuff a new gasket in their too. Maybe two!

[custom1970]

I had the same problem, I was able to stop the leaking by getting some cork gasket material and cutting it to fit under the rubber gasket. Lid was pretty hard to get on but it doesn't leak and was fairly easy to do.
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[Mike Quillici]

Originally Posted by custom1970

I had the same problem, I was able to stop the leaking by getting some cork gasket material and cutting it to fit under the rubber gasket. Lid was pretty hard to get on but it doesn't leak and was fairly easy to do.
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Posted via Mobile Device

This sounds like an excellent plan. Did you use a carb gasket and cut it down?

[custom1970]

No I just used regular cork gasket material. It comes in a roll, most parts stores should have it. Not sure where mine came from, I've had it for years. Comes in handy more times than you'd imagine.

[Mike Quillici]

Originally Posted by custom1970

No I just used regular cork gasket material. It comes in a roll, most parts stores should have it. Not sure where mine came from, I've had it for years. Comes in handy more times than you'd imagine.

Something like this then?

http://www.autozone.com/autozone/acc...ier=67679_0_0_

I figure 1/16" should do the trick, yes?

[custom1970]

i believe that would do it, good luck!

[Mike Quillici]

Beautiful. Thanks so much. This has been driving me crazy for over a year.

[travisfraughton]

Originally Posted by custom1970

I had the same problem, I was able to stop the leaking by getting some cork gasket material and cutting it to fit under the rubber gasket. Lid was pretty hard to get on but it doesn't leak and was fairly easy to do.
Posted via Mobile Device
Posted via Mobile Device

Excellent idea, this has been bugging me for the last year almost, I've tinkered with the clamps and tried to tighten it down, but that seems like a much more simple and logical solution. Thanks!

[Mike Quillici]

Custom1970, you are a genius! It appears to have worked like a charm. Nice and tight. No more leaks. Thank you!

[GRX]

Good job on the cork. Have seen that done before. Let's keep in mind that if fluid is coming out moisture is getting in. Rusty surfaces don't mate well.