930 Floating Rotor on 3.2 Query

[Highfield]

I have read so many articles on the 930 brakes on 3.2 debate, that I have thoroughly confused myself (not hard)! Help Bill !

I have an opportunity to get hold of a set of 77/78 floating rotors, hats and hubs as a complete set along with 930 front calipers. I am told this will bolt straight on to my 86 3.2 Carrera front - is this correct, and if so, can I use the existing mounting hardware and brake lines ?

I also have the opportunity to buy a set of 930 rear calipers in the same deal, but NO rotors. What rotors do I need to bolt straight on to my car ? Where is the best place to source them (I am in the UK).

Finally, do I need to remove the proportioning valve ?

Thanks in advance for your help in clearing this up for me.

Will post pics etc. assuming I go ahead.

[dean]

78-79 930 is what you are talking about I think. If they are factory 930 hubs they will not fit a Carrera unless you have 930 flares.

To fit the rears you have to have the calipers mach. and stock 930 rotor fit fine.

Dean

[Dennis Kalma]

I have them on my '75, I had to upgrade to mid-80's (forget the year) struts with the larger spacing to hold the front calipers. I machined my own dog set up (the pieces that hold the front rotor in place) and it has worked pretty well, albeit a bit noisy, which I think is caused by too great a clearance on one side.

I needed to fit some spacers to get the calipers mounted correctly, Porsche has some thick washers (about 3 to 4 mm) that are perfect.

I installed power brakes (needed to cut out the trunk floor section and fit all the related stuff) and also put in the proportioning valve. There are at least two of them in the Porsche repertoire, I went for the one that allows the highest use of the rear brakes (55 bar I think) and quite enjoy the fact that I can't really lock the rears first no matter what I try.

The rear machining for calipers was a pain. I had no trouble with the trailing arm (need to take off the ears that hold the splash shield), but sent the calipers away to be changed by a so called "expert" firm. They screwed up and drilled the holes in the wrong place. I needed to fill those holes (welded up) and get them redrilled locally. It is not a big deal to do if you have the stock rear Turbo rotor and caliper, a bit of measurement and templating and you can get it pretty well exact.

The thing to look for is to ensure that the outer edge of the brake pad is right at the edge of the rotor (not too far in or out)...sort of flush. You will have some fun fitting the rear caliper as there is not much clearance for the bolt and washer, I cut down a socket so I could get in there with a rachet...worked well.

Great result though....I couldn't lock my brakes with the "M" calipers and the rubber I am running, now there is lots of brake capacity.

[Highfield]

Dean / Dennis - thanks for quick follow-up.

I do refer to 930 calipers / rotors, but I have a narrow body 86.

I have the standard proportioning valve - is this OK ?

Is Dickster there ? - as I believe you have a setup like this in Scotland !

[JeremyD]

Go the 993 s/4 set up that Bill Verburg recommends. Less cost and less headache.

[ChrisBennet]

In the front:
The front I think the brake calipers will require an adapter but will otherwise bolt on. (Not sure on that.)
The '78 & '79 930 hubs had a spacer that you can remove and then you can use them on your '86.

In the rear:
You will need to have the calipers machined. VCI is the most expensive place to have this done. Powertech will do it a lot more reasonably.
The trailing arms will need to have the ears (for the dust sheild?) cut off ("Vangoughed") and you will need to make up some hard brake lines. You may also need to swap around the brake lines and bleeders.

-Chris

EDIT: Doh! I didn't notice you weren't in the US.

[Highfield]

Jeremy, total cost is looking like £750 ($1400) if it will bolt on, so plus any machining for the rears if required. What was the 993 / S4 setup working out at in cost - I have read your posts and do like the look of them.