1986 MGM 5.0 Master Cylinder Cao-n-gasket

[gadget73]

The inside of the bore rusting would be another concern. its cast iron, and the seals are just rubber. Run rubber bits over rust a few times and its done.

master cylinders are stupid simple inside, just a couple of seals, a piston, a spring, and a snap ring to hold it all together. The only real way a new one could be screwed up is if they didn't clean the bore up after machining it and there are sharp edges where the holes are drilled into the bore for the outlet and the reservoir. That actually happened to my boss with a prop valve he put on his sister's Heep. 2 months later and it was spewing fluid out of somewhere that shouldn't have fluid. Took it apart and he found a burr that sliced the O ring seals.


I actually have an old un-used master cylinder for my Continental that Scott gave me, it was a spare for the SVO he had years ago. Its probably pushing 20 years old at this point. I should see if I can even find a rebuild kit for it

[Toploader]

So, NOS or store brand X?

[Mainemantom]

I would go with a name brand master cylinder with a lifetime warranty. I always buy the master with a new booster. Saves doing the job over especially if brake fluid leaked inside the booster. Just my 2 cents

[gadget73]

yeah, often they won't warranty the booster unless it goes with a new MC either. If the MC is leaking fluid back into the booster its just a matter of time until the rubber fails.

[friskyfrankie]

+1 on doing the complete job unless you enjoy doing it twice.

[Toploader]

Ok do not shoot me!...............my master is not leaking!..........the only reason I thought of its replacement was because I want to replace all of the brake lines, and thought WTF, might as well do the master as well. Is this a crazy thought??

[friskyfrankie]

Depends how old the MC and booster are. The system must be bled anyway so why not unless it is a financial issue.

[Toploader]

Depends how old the MC and booster are. The system must be bled anyway so why not unless it is a financial issue.

I assume they are in there since new. I purchased the car from the original owner.

[friskyfrankie]

Then it becomes a personal preference but since you are doing all the brake lines......

[Toploader]

LOL..............and then there is my Avanti that I need to do brakes and wheel cyls on..................yea the old car hobby surely drains ones wallet;-)

[friskyfrankie]

Cars are like a "needy" girlfriend/wife. LOTS of attention ALL the time!