Chase the master cylinder.

Posted October 9th, 2010 by admin

Groan.

Went to bleed the brakes, found brake fluid dripping from the joint between the cylinder and the servo, deep joy.

Okay, lets get a master cylinder!
Easier said than done.
I’ll have to write this down as I’m getting confused now, I have a scrap of paper here that has just loads of numbers on it, I had better write it down in some nice format before it gets lost!

Original iltis Master Cylinder VW No. – 183 611 019
All well and good, that part number does not cross refer to any other aftermarket part number – bums.
Okay, bit of lateral thinking, This is a car badged as a VW but designed and built by Audi.
Designed in the mid seventies, so lets choose a mid seventies large Audi, say a 100.
Bingo, a A100 uses a very similar if not the same cylinder, same dimensions 23.81mm bore (15/16′s) and 19mm/17mm stroke (dual circuit) and we come up with a Audi number of 431 611 019 A, brilliant.
The part number of the repair kit for the Audi 100 part and the VW Iltis part match at 183 698 181 B.
So, reasonably confident that this is the same part, but kinda old so no one has bothered filling in the cross ref data, no big deal.
Next, take Audi part number and see if that crosses over, woopee f**kin doo, it does, 3 brands
TRW – PMK128 (obsolete)
TRW – PMK138 (obsolete) how does this differ to the one above?)
UBD – 82792 (no info yet)
Bendix – 132273B (obsolete)
This is not looking good!

During this search we also threw up another couple of Audi part numbers
431 611 019 F
431 611 019 J
I have no idea what the difference is!

So, not having much luck here, master cylinder does not appear to be available, the repair kit doesn’t appear to be available, where do we go now?
I then put the repair kit number into ETKA’s “ATP” search function and this throws another model up!

Audi Quattro Sport 1980 to 1991 uses the Iltis repair kit, same 23.81mm bore and 19/17mm stroke…. hhmmmm.
Even better, they do a 25.4mm version!
23.81mm Audi master cylinder – 443 611 021
25.4mm Audi master cylinder – 447 611 021.

I’m off again to chase part numbers!

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Edit, I think I would that the Audi parts do not have the check valves, and the brake light switch port is in a different place, big deal!

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