Brake wierdness

[Pighead]

Still working the bugs out after the Grand Transformation of my Pig...

http://www.pirate4x4.com/forum/showthread.php?t=288081

And I noticed a very slight movement of my brake pedal while sitting at a light.
Brought it right home and looked at the connections, all were dry.
Looked at the master cylinder, the caps were wet, and a few drops of brake fluid were on the fenderwell.
I dried everything and re-started and stood on the brakes. Good initial pedal feel, but if I stood on 'em long enough I couls get that pedal to sink another 1/2 ". Pedal sinkage was faster as engine vacuum increased.
I'm thinking that one of the O-rings in the MC is leaking, And I should be getting a(nother) rebuild kit for it,
But, Now I have these nice disc brakes in the front and the MC is the original '74.
If I was to decide on a new or re-built MC, what year and model should I ask for?
Front disc LC? Mini? 4-Runner?
I've got the IFS 4-Runner calipers, LC vented rotors, and a '74 booster.
Thanks.

 

[Poser]

Stick with a TOYOTA master cylinder, and you should get years of trouble free use.

I cannot think of any reason that you would want to go to a different master than what you are currently using.

Good luck!

-Steve

 

[Pighead]

Well, I'd heard that some MCs had different size bores for different applications.
Maybe the 4 larger pistons of the 4-Runner calipers prefered a higher pressure or lower volume than the drum wheel cylinders. I dunno.
The stock MC seemed to work fine till it felt funny.
Thanks

 

[CruisinGA]

So long as the front circuit residual valve is removed there is nothing the matter with a '74.

If I had front discs and I was buying a new master I would probably get a '76 master. Should look exactly the same as what you have, and be the same except the lack of the front residual valve.

Like Poser said, buy toyota.

 

[Pighead]

Very cool.
Just what I needed to know.
Thanks