S4 Brake Upgrade for Early 928s - 1981
#16
Rennlist Member
According to the PET images, the spindels I have in spare are S4 type (1986). So I'll try to swap them for S type spindles. Hope this works! Somebody out there with an S wants to upgrade to S4 4-pot calipers I guess!
#17
Rennlist Member
For someone to use the S4 spindles they would need everything else that goes with them. The lower ball joint mounting point changed at that time, which is why you can't mix them with early suspension components, and need to change to S4 front suspension in total if you use them.
#18
Rennlist Member
If I ever get the spacers we measured out to be correct for an adapter, you can use the existing single piston calipers and go with the 13" rotors and have performance that will blow away the S4 set up and it wont cost much more than 2 bolts and the spacers!
#19
Rennlist Member
Andre,
Have you resolved your turning rub, not straight forward. I have the same turning rub after upgrading 1980 to S4 front brakes. Rub is sporatic and not consistent. I replaced lower aluminum ball joint with steel.
Thanks,
ED (sandersedward@sbcglobal.net)
Have you resolved your turning rub, not straight forward. I have the same turning rub after upgrading 1980 to S4 front brakes. Rub is sporatic and not consistent. I replaced lower aluminum ball joint with steel.
Thanks,
ED (sandersedward@sbcglobal.net)
#20
If the guy from Tuttle Oklahoma is on here, chime in and give us an update on the Cayenne rotor/ Wilwood caliper swap. As soon as I can get to it I'm going to build adapters for The Boxster S rotors and Wilwoods on the Early 928's as well.
#21
Rennlist Member
The S4 brake update kit may be interesting but I have a complete S4 front and rear suspension eating up space in my garage. It is "used" to put it mildly. It will need new upper and lower ball joints (already in stock, would need them anyway for the old suspension), new bearings, new discs, and off course a set of S4 calipers or something like that, and that part I don't have! I can buy a set of GT calipers (4 of them) for approx EUR 500. I would prefer an "S" setup but then I would need a set of "S" spindles too.
How about the fitting of the rear calipers on the rear suspension? From the PET 1982 and 1986 I conclude that these are the same (same number) so the old ones should be fine. Only the deflectorplates should be S4. Am I correct so far?
How about the fitting of the rear calipers on the rear suspension? From the PET 1982 and 1986 I conclude that these are the same (same number) so the old ones should be fine. Only the deflectorplates should be S4. Am I correct so far?
#22
Rennlist Member
You're in luck .... you have S spindles.
Those suspension components are from and 84 or 85 S when ABS was optional ... they are not S4. You can easily tell the difference as the S4 spindles have caliper mount bolts which are radially oriented, whereas the S spindles have caliper mount bolts which are on the same axis as the hub spindle.
You can retrieve those spindles from what you have there and clean them up ... then post a pic of the spindle itself to show if there is any wear of the spindle from the hub bearings.
You can put S shields on and use your old hubs with new bearings, fit new discs, renew your worn BJ's, ditch the ABS sensor on the knuckle, fit S calipers and new pads, fit new flex brake lines, bleed and you're done.
Those suspension components are from and 84 or 85 S when ABS was optional ... they are not S4. You can easily tell the difference as the S4 spindles have caliper mount bolts which are radially oriented, whereas the S spindles have caliper mount bolts which are on the same axis as the hub spindle.
You can retrieve those spindles from what you have there and clean them up ... then post a pic of the spindle itself to show if there is any wear of the spindle from the hub bearings.
You can put S shields on and use your old hubs with new bearings, fit new discs, renew your worn BJ's, ditch the ABS sensor on the knuckle, fit S calipers and new pads, fit new flex brake lines, bleed and you're done.
#23
Rennlist Member
You can also use the lower shock mounts from those in the photo after cleaning up as they have the right length bolts for the steel BJ carriers .. and you can use the air deflectors.
You could also use those steel BJ's ... if they're OK ... that's an if because they don't look good.
You could also use those steel BJ's ... if they're OK ... that's an if because they don't look good.
#25
Rennlist Member
Well, this truly is good news. Old scrap becomes gold. Thanks a lot Dave, your comment truly saves me a lot of research and therefore time. So the easiest way to upgrade from my standard non-S brakes is mount S-type calipers on the spindles I already have. I also have new LB's (old ones completely shot). I also have new brakelines just waiting to see the light of day. So the shopping lists is:
- brake discs S-type
- S-type calipers (EUR 200 for set of 2 fronts)
- probably a repair kit (seals etc)
- deflector plates
- brake pads
Optional:
Rebuild the A-arms. Old ones from my car are fine (not from the picutre) but I would like a sharp turn-in so using the slightly harder bushings from 928 motorsport is tempting.
Very easy conversion now with all of the front suspension is taken from the car for rebuilds etc.
- brake discs S-type
- S-type calipers (EUR 200 for set of 2 fronts)
- probably a repair kit (seals etc)
- deflector plates
- brake pads
Optional:
Rebuild the A-arms. Old ones from my car are fine (not from the picutre) but I would like a sharp turn-in so using the slightly harder bushings from 928 motorsport is tempting.
Very easy conversion now with all of the front suspension is taken from the car for rebuilds etc.
#26
Rennlist Member
air deflector plates
Wow, it seems that the air deflector plates 928.351.083.00 and 928.351.084.00 are made of unobtanium! I hav found no company that stocks them, new or used. What is the listing price at the local P-dealer? Tomorrow I will find out. (part 3 in the PET drawing).
#28
Rennlist Member
The air deflectors I was referring to are the sweeping deflectors on the lower control arm, for directing air to the centre of the disc. I was thinking you wouldn't have them on your car ... but PET shows you do.
#29
Rennlist Member
You are right, they are not on the lower control arms of my car. But the old "used" set of suspension parts from the S2 does have them. I also have an S front bumper with the air ducts for directing air to the discs. Sorry purists! I hope I don't get kicked out of the 928 club now with the modifications I have mind. I was kicked out of the classic 911/912 club when they found out that my 911S had a 911T front end due to accident damage. It does have all the S goodies!
#30
Rennlist Member
Go for it ... I think the full S conversion at the front makes a lot of sense.
When it's all finished I'll have later brakes on my 82, some later interior bits, and quite a few engine and suspension mods ... but it wasn't pristine when I got it.
The GTS I'm keeping original and getting it perfect in every way, because its one of a kind, and it would be sacrilege to do otherwise.
You'll only get a hard time if you start talking about ricing yours, or claim you've just set the galaxy record for running at warp speed in a 928.
When it's all finished I'll have later brakes on my 82, some later interior bits, and quite a few engine and suspension mods ... but it wasn't pristine when I got it.
The GTS I'm keeping original and getting it perfect in every way, because its one of a kind, and it would be sacrilege to do otherwise.
You'll only get a hard time if you start talking about ricing yours, or claim you've just set the galaxy record for running at warp speed in a 928.