Fabio421

Hi all. I just bought some S-4 rear calipers that I was planning on putting on my car. I was going to put them on my 84. What else is required to make this swap?

In addition, what will be required to add the S brakes off of the 84 to my 78? Thanks.

Jim bailey - 928 International

You just need a couple of spacer washers to center the rear caliper and S-4 rotors. To put S front brakes on an early car you need S spindles the rearas are the same...

Fabio421

So I need S-4 rotors? Ok, sounds good. Are these washers special or are they just flat washers? Also, where would I put the washers exactly?

Thanks.

Jim bailey - 928 International

Porsche never used a washer but find some which moves the caliper in just enough when placed between the caliper and the mount so that the caliper is centered on the S-4 rotor.

Fabio421

OK. This didn't work out as planned. The S-4 rotors are too wide. The "hat" is too deep and the disk is hitting the suspension way before the hat sits flush with the hub. What is wrong here?

Peter F

Not sure what you got there but it does not look like S4 rear disc to me.

/Peter

Fabio421

These are Zimmermann cross drilled rotors p/n 460 1516 .50 (for the right side)

Rob Roy

Just spent all day working on my brakes - and thats not a S4 rear rotor - the hat is way too tall

Imo000

Yes, that's not an S4 rear rotor. I jsut came in fromt eh garage ans was looking at the S4 off the parts car and they are, as said above, shorter.

Also I have installed S4 rear rotors on my first 928, and '83, and kept the original S calipers. They are almost bolt ons. All I had to modify is to have the outside diameter of the rotor slightly reduced and that's it. The S4 rotors are much thicker than the S.

Fabio421

Can anyone tell me what these are supposed to fit? Not only was I sent the wrong type of rotors, I was also sent two right rear rotors. I was also shorted an oil filter in my order. WTF? Thats what I get for using a FL Porsche supplier to save time. Lesson learned.

hacker-pschorr

They are probably for some wide body 911.

Fabio421

The vendor is insisting that these are the correct rotors. Can someone please provide me with the correct p/n from zimmerman for an S-4 rear rotor? The # stamped on the lip of these rotors is 1516 51

Thanks

Jim bailey - 928 International

Maybe for a 911 4 S Wide body car but not a 928 S-4 ! They probably have no idea what was in the boxes and sometimes parts get mismarked, it happens. You wanted 951 352 041 60 to get holey rotors as used on the 944 Turbo ...

Fabio421

OK. I exchanged the rotors for the correct parts and have finished this project. I like the way it looks alot. For those of you who are doing this mod, you will need two standars 12mm flat washers between each bolt flange and caliper mounting hole. You will also need to cut off the electrical plug on the end of the pad sensors and crimp some female spade terminals to adapt to the old wiring harness. I re-used my old rubber boots and just slid them on before crimping on the new terminals.

Rob Roy

Looks Great!