Hi.

As it seems, I have the correct spindles for the brake upgrade to the 4 pots.
What year & model calipers will fit with the "convert" bracket? What should I buy, and what brake discs will fit? (Diameter?) I`m looking to get used parts.

Any advice appreciated!

Cheers
Jørgen

 

If I remember correctly the 81 model year does have the correct spindle for the conversion adaptors, they should be 74 mm between the mounting holes, The rotor for the conversion is a 993 rotor and can be had in either 304 mm or 322 mm. The 304 mm rotor uses the Brembo caliper from the 86.5 S or the 87 on non GTS cars. There are some minor differences between the years on the calipers but any that are a matched set will work. The 322 mm rotors use the "Big Blacks" from the GTS. The 304 mm rotors will fit under stock 16" rims, the 322 mm rotors will require a 17" rim at a minimum. Before any front brake upgrade you should upgrade the front lower balljoints to the steel versions, if not already done. Both the S4 Brembo calipers and Big Black Brembos were uses on other Porsche models so they can be sourced from non 928 cars. Your current backing plates will either need to be replaced to fit the larger rotor size or eliminated as others have done. The conversion is a 2 on the 10 scale of difficulty. If you undertake it the conversion I reccomend you flush the entire brake system and replace the fluid with ATE Super Blue.

I remember 928 Specialists having a listing of parts needed for the conversion on thier site, you might want to check it out of part numbers.

Paul

1980 Euro S Red/Blk Lea

 

[QUOTE=VT928;10122012]If I remember correctly the 81 model year does have the correct spindle for the conversion adaptors, they should be 74 mm between the mounting holes, The rotor for the conversion is a 993 rotor and can be had in either 304 mm or 322 mm. The 304 mm rotor uses the Brembo caliper from the 86.5 S or the 87 on non GTS cars. There are some minor differences between the years on the calipers but any that are a matched set will work. The 322 mm rotors use the "Big Blacks" from the GTS. The 304 mm rotors will fit under stock 16" rims, the 322 mm rotors will require a 17" rim at a minimum. Before any front brake upgrade you should upgrade the front lower balljoints to the steel versions, if not already done. Both the S4 Brembo calipers and Big Black Brembos were uses on other Porsche models so they can be sourced from non 928 cars. Your current backing plates will either need to be replaced to fit the larger rotor size or eliminated as others have done. The conversion is a 2 on the 10 scale of difficulty. If you undertake it the conversion I reccomend you flush the entire brake system and replace the fluid with ATE Super Blue.

I remember 928 Specialists having a listing of parts needed for the conversion on thier site, you might want to check it out of part numbers.

Paul

1980 Euro S Red/Blk Lea[/QUOTE

Great info! Thanks for the input- I do have the 74 m.m. spindles, and the alu lower balljoints, so they will be changed also! Are there 2 different conversion brackets using the 304 vs the 322 m.m. rotors, or is it the same?


Jørgen

 

jorgens

I would reccomend you replace the Aluminum ball joints ASAP, if it were my car I would not trust a part that is 32 years old and has a history of failure. There is only 1 conversion bracket, there are however 2 different mounting bolts. The shorter length is us used for the S4 Brembos with 304 mm rotors and the long ones for Big Blacks with 322 mm rotors.

Paul

1980 Euro S Red/Blk Lea

 

the easy answer is to get the adaptors from a supplier

http://www.mailordercentral.com/928i...351%20999%2098

then its a simple bolt on to upgrade to 4 piston calipers from an 86.5-91 S4

Also replace the ball joint to the steel version

 

Thanks guys!


Jørgen

 

Jorgens, Click here: https://rennlist.com/forums/928-foru...otor-swap.html Great setup. If you don't like the Wilwood script, just grind the lettering off the face, spray with high heat paint then stick on the "PORSCHE" vinyl letters. T

 

993 rotors arrived today, but when installing, the inside is touching the lower balljoint.. Anyone experienced this, if so what is the solution?


Cheers
Jørgen

 

Jorgens,

You have an aluminium lower ball joint!
DO NOT DRIVE THE CAR until you replace that with a later steel unit!

You need two ball joints, and two larger eccentrics.

 

I know, I have the new steel ones on the shelf but I need to get to a lift first.


Jørgen

 

the steel ones are smaller and will not hit the rotor....

 

Then; Problem solved
Thanks!

Jørgen

 

Just one more: can I use std brakehoses from a 88`928 after installing the calipers from the same car? Will they fit in terms of length?


Jørgen

 

Now, we`re happy

Jørgen

 

I just had to churn out a set of adapters for the Lexus calipers because nothing else fits this rotor depth and 993 wheels.
Will you be using big reds/blacks?