I am going to stop trying to figure out what the deal is with my brake system, and just buy a new master cylinder. I used the vacuum method that Wally told me to use and was able to get fluid out of the master for a moment, but then it clogged up again.

I figure a new master cylinder cant hurt.

so what years ar compatible? its weird, I can find a 1978 for 100 bucks reman

but a 1980 us 200. can someone tell me which years will work in my 1980? Porsche I thought rarely changed a part like that year to year without a significant upgrade of some kind. Maybe I am wrong about that. I would like to order one today so any help is appreciated.

 

something weird I just noticed... the part number for the 78 and the 80 are the same on a different site. The first site I went on lists the 78 MC for 100 bucks including core, but the 80 200. if another site has them as same part #, then they are the same no? WTF?

 

ok I figured it out. one is 200 and includes both switches. the other is 100 and doesnt. The two switches look like standard sending units and are on top of the MC and have 3 blade type connectors. What is up with that?

is my 80 supposed to have those switches on the top? I dont remember seeing them on it.

 

The switches are on the bottom...

 

ah ok that makes sense. Hard to see when it is in the car. I thought the lines from the bottom went to those bias regulators. I didnt realize there were also small switches there. what do those switches do? I assume they are pressure sensors of some kind. I found them for 15 bucks a piece so I think I will buy them seperately and not pay 100 dollars to have them installed.

 

also, good idea to replace reservoir also or no? Some of them come with reservoir installed as well.

 

I was thinking about replacingthe booster in the 80 while I am doing the master. I found a used one from an 82... it has been fully cleaned and inspected by the company. here is the link: http://www.ebay.com/itm/82-PORSCHE-9...f05f57&vxp=mtr

is this a good idea? I mean for 149 I get fully functional booster, switches and everything.

 

First off... Look up your part by number and use the Porsche P/N for confirmation. Some sites will offer the wrong stuff. Get the PET program, or PET PDF version or use a part vendor site (Pelican, 928I) to get the P/N.

If you think you need a master cylinder then get a fresh one and not a "guarenteed" used one. That just means you'll get money back if it fails and you do the testing.

The two switches control the brake lights. There are two pistons inside the MC and if they don't both switch it's a fault and those dash lights come on. Those are common VW parts and available for $5 to $30. Get a good one as the cheap ones fail.

If you don't need a booster then don't get one. Get new rubber grommets for the reservoir although those should come on a rebuilt master cylinder.

 

Just call Roger at 928s R Us, he will take care of you

 

This.

If you start hunting around on the web and trying to figure out which one to get from places like Rockauto, you'll very likely end up with the wrong part, and probably pay more for it too.

 

I hear good things about that company. it seems that the major 928 parts companies tend to be a little or a lot bit higher in price than some of the places that dont specialize. I am new to the game however, and that could just be how I have seen it thus far.

 

Phone roger, then compare prices, then phone roger again

 

You need 928 355 011 04 which fits 78 to 83 cars and my price is $239.95.
There is a rebuild kit 928 355 913 00 for $100 (Porsche).

 

I got a new one from Roger a couple years back, still working great! Thnx agn Roger! I would not however recomend rebuilding it. The bore tends to get worn and pitted, espesialily along the bottom, and the forward piston would be a real bear to get out. But hey it's your car, do what you want.
Just my .02 worth

 

I am not even thinking about a rebuild. Thanks Roger for coming forward with the price. I found another price on a master cylinder (rebuilt). If you pm me I will tell you the price.