Bambam7

I have REALLY bad leak from my master cylinder- it goes through the whole tank every few days.
It's leaking from the o-ring grommets that seal the plastic resevoir to the piston.
BUT- I can't pull the resevoir off!!
In the haynes manual it says that the resevoir should pull offf my rocking back and forth and pulling up- but no dice! It also says that "later model" resevoirs are held on by a screw... well, mines a '90, pretty "late model" and I don't see any screw holding the resevoir on!
Anyone have any input this? I need to replace the O-rings ASAP!

SonicRaT

iTrader: (6)

My rings are leaking as well, I've tried pulling, pushing it a little back and forth, and it just doesnt seem to come off, I've looked for that screw myself with no luck, and I have a '89 GXL. I wish someone could help us!

rico05

I am just gonna drain the resivour w/ a syringe, then use some silicone sealant to seal it around the bottom of the tank.

SonicRaT

iTrader: (6)

Hey rico, get on AIM

duboisr

garfinkle replaced my leaking tank it pulled off .He put in new rings and coated them with brake fluid and pressed the tank back down . It was to get down but after three tries it sealed

Icemark

Yes the series 5 have a screw at the bottom. Once its removed its pretty easy just to pull up and out. You will break the res removing it without removeing the screw. You might try using a small mirror to see where the screw is if you can't see it very well. The haynes manual actually has a great view of the res and screw (and brake master assembly).

I also recommend fender covers and putting syran wrap under the res cap and then tightening the cap down to form an air tight seal. The vacume created will help keep the brake fluid in the res while removing.

Also have a small plastic bucket underhood, that you can quickly drop the res into and then lift the bucket and all out of the engine compartment. This will minimize any chance of spills of brake fluid onto your painted surfaces.

Bambam7

My Haynes manual shows no screw.... I asume there is one- but where is it??? Inside the tank? On the cylinder?? what?

ponykiller

I found it a royal bitch to remove the resevoir. It takes a lot of pulling, but that is the easy part. The re-instalation is the true pain in the ***. I finally gave up and purchased a new Brake Master Cylinder assembly, and installed that. I figured that if the grommets were leaking, some seal inside was also probably leaking.

The screw is there, look underneath the master cylinder.

Kris

Sniper_X

I have a 1991 'vert...

Theres no screw on that car. theres probably no screw on yours if you have looked REEEALY hard and didnt find one.

I don tknow why this is. there is supposed to be a screw.

Sniper_X

Bambam7

Conclusion- - I am just going to dry it off, clean it, and seal the base with epoxy.
I figured that if taking it off was that hard, reistalling it would be a huge PITA.
Here comes the epoxy....

busy13b

iTrader: (5)

My MC was leaking from the front o-ring as well, and I haven't the time to rig my 929 MC up yet, so I wanted to fix my leak.

As a reference point, my '90 GXL MC is the factory original and had no screw to hold the reservoir on.

mY 929 MC does have a screw holding the reservoir on, however. It is located at the bottom of the fluid reservoir, between the two "drain ports" -- if you are looking for a screw.

To get the reservoir off, make sure you drain all brake fluid out first, as it does very bad things to car paint!!

Also place a few rags in the surrounding area to be on the safe side.

Once drained, unplug the fluid level sensor (if you hadn't already done so). Then grasp firmly on that sucker and pull like all hell I found it helps to kinda wiggle the reservoir around as you are pulling. The plastic is strong so it will take plenty of abuse before breaking.

Once out, I also took out the big rubber o-rings (with a needle-nose pliers), then thoroughly cleaned my fluid reservor and the o-rings.

I lubed up the o-rings with Vaselene, popped them back in and applied red RTV sealant around top of the MC pedistal. I also put sealant around the base of my reservoir, let set 10 miutes and reinstalled.

You have to push like mad to reistall the reservoir, but eventually it will pop back in place. I let the whole deal cure overnight before putting in new brake fluid.

Of course, you will want to bleed your brakes after doing this proceedure, as mucho air enters the lines.

stabben

Hi!

My first post here in this forum!

In case you haven't already done the epoxy bit, here's my experience on the matter. I have a '91 convertible and recently replaced the MC o-rings/bushings. There's no screw on mine, and I just pulled like mad on the /%#" reservoir until I finally gave up and simply levered it off with a big screwdriver. I had no problems with the plastic cracking, it held up fine. Then I had a fun time fitting the new bushings and finally cursing and pressing on the reservoir to get it back in place. A couple of hours, at least, to get it all done! I also used a syringe to first empty the reservoir of all the fluid. Much less of a mess!

The new bushings are tight and I haven't seen any leaks yet, even using synthetic brake fluid. I flusjed the entire brake system and bled it. Will do a more proper bleed again next week, however.

Good luck!

Icemark

How hard is it to find this screw??? I can't belive that anyone has trouble finding it.

Item #2 in the drawing.

Bambam7

Heh- definately NOT there on mine.
My whole assembly looks alot different from that too.
Just a lot of force required I guess. pretty bad.

Icemark

Well thats the series 5 assembly. So if it doesn't look like that then the wrong series assembly (more than likely a cheaper series 4 assembly) was used as a replacement at some point.

No big difference other than shaft length (the series 5 has a slightly shorter piston shaft assembly and the the screw)

SonicRaT

iTrader: (6)

Yeah, mine is completely different as well, and no screw. 89 GXL