Master cylinder choices

I'm looking to replace the master cylinder in my Rabbit GTI with something new. I've replaced everything else in the brake system in the past, but mine is looking pretty rusty, and I'd feel better with something new in there. I'm seeing stuff on ebay, but most don't have the 3.25" mounting holes needed for the power booster. What other MCs are acceptable to run: either by braking ability or following the rules.

Are new Beck Arnley or Bendix MCs OK, will they last in a race car, or should I just go with the good German stuff (which I can still get cheaply) - just wondering.

ETKA says the proper part # for the GTI is:
175611025a. But other Rabbits like the pickup(Caddy) and 80-84 Rabbits use the same mounting hole spacing and same diameter of the MC piston (20.6mm) but different part #s. I'd like to stick with these specs, but do I need the specific part # listed for this part or will something similar work?

Thanks,
PJ

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83 Rabbit GTI - future ITB

It might be useful to separate the rules question ("What is legal?") from the technical question ("What will work?"). They are very different...

Technically, anything that fits and has the same bore diameter will do the job. It MIGHT even be that something that is a little different will work but that gets funky.

In terms of IT-legality it's technically not even allowed to run an OE-equivalent aftermarket part, as silly as that is.

K

To the IT rules, only the OEM-specified master cylinder is allowed. One can also argue that only OEM-sourced parts are allowed, though that's been a source of debate in the past.

Given this, I'd suggest that any item from your local aftermarket auto parts supplier that is listed as the specified replacement for the 83-84 Rabbit GTi is an acceptable part.

It's highly unlikely you will get protested or tossed for using an aftermarket equivalent part (I personally feel that's within the spirit of the rules) but using a master cylinder not specified for your car is definitely not within the spirit or the letter of the rules.

I'd suggest watching eBay. I see good OEM VW master cylinders pop up all the time.