911 master cylinder in a 914. Ok but 20mm?

[farleyd]

Hi to all. I know that i can put a 911 mastercylinder on my 914. The 19mm one.

The problem is that on the one i bought, there is a 20 written on the bottom. I never heard of a 20mm mastercylinder? Am i wrong? If there is a 20mm, is it too large for a 914? My set-up consists of a 1984 911 Carrera front strut assemblies w/calipers and stainless steel brake lines.

BTW My stock master cylinder on my 914 was marked with a 13???? 13mm??? Possible???

Thanks to all.

[efeinsmith]

The stock master cylinder for the 914 was a 17mm unit, so the number you found is not the bore diameter. The 911 master cylinder is a 19mm unit, but I don't remember where the part number is on the casing (I'll look tonight at a spare one I have).

[farleyd]

I started the topic. I have my M/C in hand. How can i identify it? I had contradictory infos regarding the possible existence of 20mm M/C.

Here are the infos that appears on it:
ATE (brand i guess)
small 10 numbering (near the bolt holes)
bigger 20 numbering (on the otehr end)

There seems to be no part number on it.

Thanks.

[DDS]

My stock MC had a 'meaningless' number on the bottom and the bore size marked on the top. You couldn't see that latter with the unit in the car.

Dave

[John Rogers]

You can pull the rubber boot off and measure the bore diameter and compare it to your old one.The 17mm should measure about 43/64 inch and the 19mm just about 3/4 inch. If you don't have an inside mike, wet the flat surface of the bore area (mine had a flat surface surrounding the bore) and press it against a piece of paper and measure to get a close reading. Good luck.