New brake master cylinder locks all wheels

[mspohr]

My 2000 Disco II had classic signs of leaking brake master cylinder (squishy pedal slowly moved to the floor) so I bought a new (non OEM) master cylinder and replaced it.
It works fine except after driving (stop and go) for 5-10 miles, the brake pedal will be fixed in the up position (no play) and it seems like all four wheels have the brakes applied. It's difficult to drive and the brakes start smoking and getting hot.
After it sits a while, the pedal action returns to normal.
The vendor of the new master cylinder has come up with all kinds of suggestions (but not a defective master cylinder).
I think the new master cylinder is defective.
Anyone have any ideas on anything I could check before replacing it again?
I've tried to "reseat" it (remove and retighten) but still has the problem.

 

[discostew]

Make sure you didnt change the brake light switch adjustment . Pull it back off the booster and make sure fluid didnt leak into the booster . Thats common and destroys the booster . But if this wasn't happening before your probably ok on that.

 

[pinkytoe69]

If you search the various forums, you will find that it is a bad idea to go with a non-OEM master cylinder.

Doing so seems to inevitably result in issues like you describe.

 

[mspohr]

I think I have learned the lesson to avoid non OEM parts (the hard way).

 

[robertofollia]

It has happened in D1s and D2s as well, even with OEM and gen-you-win master cyls.
A friend of mine had the same problem after 5 minutes. They went crazy.
It was something as stupid as the free play adjustment nut. For some reason the "new" cylinder had less tolerances and as soon as you fitted it, it appeared as if you were braking, at least a little bit, so that caused the binding.
Adjustment of the nut regulating pedal free play or a gasket between cylinbder and booster (check the original gasket is not still attached to old cylinder) cured the problem
Good luck!

 

[mspohr]

Thanks for this information. It's an interesting explanation of a possible source of the problem.
I ended up buying a new OEM master cylinder and installing that. I haven't had the problem (yet) with the new OEM master (keeping my fingers crossed) but if it happens, I'll explore this avenue which could be the problem.