VikingTrad3r

if any of you have tried to install a replacement grommet at the base of your master cylinder reservoir without any special tools you will know the frustration.

I looked in the shop manual and there appears to be an upside down cone pointy side up, tool that the factory would use, to install the grommet. using this tool and a press they install the grommet on the bottom of the white reservoir and then press the reservoir over top of the cone shaped tool that sits on top of the metal part of the cylinder and stretches it enough to get it over the ridge as you press it down.

well I do not own that factory tool, and I do not own a press. So this is how we did it it may help you in the future if you need to carry out this operation. We had brake fluid leaking from both of the grommets at the base of our 1985 master cylinder reservoir's.

you will see in the photos we first tried plastic from a plastic funnel which promptly cracked from the pressure. I didn't sacrifice a turkey baster that I used to sleep things up out of the car in certain situations. That works great. It's critical that you make the diameter of the base of the cones equidistant to the diameter of the flange on the master culinder.

even after pressing it on, we still needed to use a c clamp and a socket and carefully press the oring down flush into the base of the reservoir.

we also lubed with a tiny smear of grease so it slipped nice.

pics:

<br > <br > plastic broke<br ><br > <br > <br > <br > <br > <br > <br > <br > this is what it needs to look like<br ><br >

VikingTrad3r

my phone is on the fritz it seems, having trouble uploading pictures. And that one random photo of a red mixer in the background I have no idea where that photograph even came from. It's not even on my phone. Just ignore that photograph

JackDidley

It appears you have been rebuilding a distributor, in the kitcken.

VikingTrad3r

just reporting back saying the grommet fix worked. no more leaking.

so fyi, if you find a leak at you mc, check the gromments its actually an easy fix with the cone-tool shaped in the pucs above.

Natty C

@VikingTrad3r I don't know exactly what you mean by this part...


''even after pressing it on, we still needed to use a c clamp and a socket and carefully press the oring down flush into the base of the reservoir.''

What do you mean by press the o-ring down flush into the base of the reservoir?

It sounds straight forward, I know, but I just replaced my grommets and they popped on pretty easy.

But the inside top part of the grommets aren't flush with the bottom of the reservoir. They sit above it.

It don't press down with a c-clamp and a socket. Not for me anyway. I think they're still leaking, even being new. I sucked a little fluid out of the reservoirs to make sure it wasn't coming out of the cap, though. Haven't went back out and checked to see if the puddle on top of the MS has came back though.

Natty C

Anyway, I just went out and checked for a puddle. It's dry.

I only filled the reservoirs to the max line and put the caps back on. Didn't drive it. But they were leaking a puddle on top of the MS after about twenty minutes.

Nothing leaking since I sucked some fluid out. And it's just been parked.

Odd. Maybe I'll replace the caps just for the heck of it.

I'm still curious about clamping those grommets down from the inside, though. Doesn't seem like they even can clamp down.

Actually, scratch that. Just went back out and it's wet again. Really wondering if my reservoir might have a slight crack in it.

VikingTrad3r

This was back in my early days. But I recall the grommets were VERY TIGHT AND DIFFICULT. you are saying you grommet/oring doesnt sit flush with bottom of white reservoir. I cant recall exactly but id just grab a big c clamp (like what is used for break pads) and press the rubber in. Picture of it above. Mine was dry after this install.

Natty C

I cleaned it up nice and good before closing the hood on it yesterday. Just went out to check this morning. It's still all bone dry.

This is the second time I've replaced these grommets and they probably weren't even the problem.

I think the caps need replaced, honestly. I think that's where the fluid was gettng out and running down.

After I sucked it a little below the Max line in both reservoirs and got everything cleaned up, it's stayed dry.

Anyway. Thanks for chiming in.

Good pictures, btw...

pedricd

My last master I thought was leaking too…it was definitely the cap. There is a stream of fluid that gets shot up every time you hit the brakes right at the cap. A poor cap seal allows fluid to escape and moisture into the master due to poor seal. Not a good combo. Caps are cheap at the local auto parts store. A new cap stopped my leak but when I went to put in a bias spring I found my master pretty gross inside (due to PO lack of maintenance and moisture) and replaced the whole thing.