MGB: MC Leaking

Looks like my rebuild isn't doing the job on the brake Master. Guess I'll pull it out and have power brake exchange rebuild it, must need to be re sleeved. This is the first rebuild that I've done that didn't work out.

I have two I think good master cylinders Swamper.

What kind of price you looking for?????

The most common cause of leak is the seal between the tank and body on the integral system. As far as I can determine I am the only source for the proper seal. FWIW

Swamper you have a PM.

I already bought that from you for this one, it looks as if it is leaking at the front end.

DOH....I'm not clear on how or where it can leak on the front end...The bore opens to the back or passenger compartment....would like to help but don't understand....

It is leaking wear the push-rod for the pedal enters the cylinder.

Well that is where they do leak! Are you useing LMA fluid? Were the bores scored or pitted? Did you hone the bores?

I did hone the bores very well but I can't remember how bad they were pitted if at all. I use LMA in all my cars as this is recommended by Power Brake Exchange who rebuilt my servos. Installed all new rebuild kit and reservoir seals from you.

Were the seals installed "wet" with fluid or the grease pack included? I am grasping at straws as it appears the unit did function after the rebuild so the parts were good. Even the wrong fluid probably wouldn't damage seals this soon. Maybe the bores were over honed....???

My reluctance to have it resleeved is based on having to again take the tank off inorder to sleeve the bores. I never look forward to that and have done it 20+ times...once the plastic feed breaks the tank is ruined.....FWIW. I'd also add that its must be the rear or first seal inside the boot...might be worth a sanitary disassembly to inspect said seal. I have a couple kits on the shelf including a Lucas/Girling....

I plan to take it apart tonight. I will need you to send me a kit for rebuild.

Robert are you saying Castrol DOT 4 LMA fluid could cause a leak?


[quote=kirks-auto]
Well that is where they do leak! Are you useing LMA fluid? Were the bores scored or pitted? Did you hone the bores?[/quote]

No Paul, the other way around....use of anything but LMA might cause seal failure....but I doubt it would be in such short time given Swamper rebuilt it I think in the past year....

After investigating the leak I've determined that it isn't the brake MC. The leak is from the Clutch Master, looks like I'll need a new one or try another rebuild of this one. Going to try to pull it out and take a look at the internals before I go any further. Anybody us one of Moss's new Clutch Master on their Cee (Part number 780-695)???? I think I used the Moss rebuild kit when I rebuilt it before (180--990).

Tehy may be closer but I am less expensive...I think....
Also have the kit.
All imported from UK....

Swamper,

I installed a fresh clutch MC in my (Don's) car this summer. It worked quite well, and I believe that it originated from Moss, though I got it from Bob @ Brit-Tek. (Apologies to Mr. Kirk, but Brit-Tek is literally 10 minutes from my house...). I did have to swap the arm that connects to the pedal because the new one ends in a threaded rod, but that was easy as can be.

I do have the old one if you want to pay shipping and give a go at rebuilding it. No promises on condition, I have not looked at it.

Tom