reuse 2 pole master cylinder warning switch?
 

About to start installation of a new master cylinder soon but noticed the master cylinder warning switch on the new part is different than the old one. The new one has what I take to be a single pole while the old one has a two-pole switch.

My question is can I swap the switch from the old one to the new one? Or given the car is entering its 42nd year should I just get a new one?

The car is a 1972 911T. I have owned it for 22 years so I will guess this is the original master cylinder.

Thanks.

I did the same procedure a couple of months ago. Swaped master cylinder and reused original 2-pole switches because the new master cylinder (bought slightly used here on Pelican) came with 1-pole switches. My car is a '79SC. No problem.

I recently installed a new ATF Master Cylinder purchased here on Pelican. I was a little disappointed to find that the new MC comes with a single pole sensor switch. I ended up using my old sensor but I would recommend that you purchase a new copper crush washer to be certain of no leaks. My old sensor worked fine and a new one is pretty over priced (in my opinion).

good to know. Thanks.

are the crush washers sold here on Pelican? Can't find them...

would like to replace the rubber boot over the switch but can't find that either...

Sorry, I said copper crush washer but I must have gotten confused with another maintenance project because the PET Catalog shows a rubber o-ring. And, that should come with the new master cylinder. When you switch the old switch into the new MC, just be sure it has the o-ring with it. It's part #999-701-343-40 but pelican shows NLA.

Also, The PET shows the rubber boot/cover to be #914-613-491-00 and pelican does have it but when it show in the Pelican catalog, it shows as a reverse light switch cover - it's probably the exact same part used in multiple places.

http://www.porsche.com/all/media/pdf/originalparts/en/E_911_77_KATALOG.pdf

Pelican Parts - Automotive Parts and Accessories - Porsche & BMW

Those master cylinder switches fail with regularity, and can be a PITA to replace. If it were me, I'd spend the few extra bucks and replace both switches with new correct ones now, while the master cylinder is out of the car and easily accessible. By spending a few extra dollars now, you'll save yourself from some bruised knuckles later.

My $.02. HTH.