Problem with master cylinder gasket

[kevinw]

Removed my master cylinder cover last night to check the fluid,went to put gasket and cover back on and the gasket won' t fit.Somehow it is 3/4" too long,the gasket is very sticky and is very thin.There's also black residue on the inside of the master cylinder.Could this happened from getting hot or a chemical reaction? Anybody ever have this problem and what do you suggest to fix it?

 

[BEATAV8]

One time when I was a youngster (16 years old or so) I accidentally put power steering fluid in my master cylinder (81 Pontiac GP). I learned that brake system seals do not like petroleum based products! Symptoms were very similar to what you've described, and my master cylinder took a dump.

 

[Chris Taylor]

Kevin brought the cover and gasket over last night for me to look at. It looked to me like the rubber had reacted to heat or chemical break down. In all of my years of working on cars and break systems, I have never seen anything like this. Keep in mind, this T Type is a 30,000 mile car that most likely has not had the break fluid changed.

I know people that have taken their TR’s to quick change oil stations and the attendant did not read the reservoir cover. This indicating the need to pump the break peddle ten times before checking the fluid level, thus causing a overfill condition. This could have been the case before Kevin purchased this car. May be it was a small amount of not brake fluid the caused this problem. I recommended replacing the brake fluid throughout the system.

I would like to know what would react with the rubber to cause it to be so deformed and thin.

Being the nice guy I am, I let Kevin use a spare reservoir cap and gasket.

 

[Chris Taylor]

ttt