Brake experts, help please

[E Ray]

I have a ’78 930 that is in need of new front rotors, ouch, in looking around for replacements besides sticker shock it looks like there are availability issues with the right side rotor.

Are there any options out there? I do know if I could find a set of hubs from a ’81 thru ’89 turbo I could go with the newer more available (and reasonably priced) rotors, that’s if I could find a set of the hubs.

OK brake experts here are the questions.

What are the difference between the ’78 thru ’80 rotors vs the ’81 thru ’89?

Can the later style rotor be adapted to the older hubs, adapters available?

Are there other more common hubs that will work with the newer rotor? With or without spacers?

Anything aftermarket that will work?

This is strictly a street car, may do a DE event but other than that I don’t intend to track the car.

Ideas comments? or do I just bite the bullet and continue to search for a set of OE rotor$?

Thanks

Eric

[82SC]

i may not have all your answers...

but here it goes:

the early rotors...forget about it...Dealers want 800 for a set of the floating rotors...these are flat and need to be used with a 25mm spacer if you have the turbo fenders (I know yours is a 930, but I got my knowledge with trying to fit 930 brakes to 911)

without the spacer you can use the full floating on the front of a normal 911

the later style are one piece with no floating hat...instead a integrated hat...with a 21mm (I think) offset. These can be used by the 930 crowd without the 25mm spacer...911 owners cannot used these rotors...boo hoo...unless they have turbo front fenders

You should be able to get the later rotors at dealers or pelican...also check ebay...there is a guy who seems to sell crossdrilled brembos for 911 and 930 all the time...

if you really want to stick with flat rotors what companies have been doing is using coleman, brembo, or generic rotors that are the right thickness and are flat rotors...but the diameter is too big.
So these guys machine the edge of the rotors to make them smaller....these are almost as expensive as the OEM early style rotors....
www.vehiclecraft.com
www.rennsportsystems.com/~porsche

If you do decide to chuck your rotors I would be interested in buying the hats off you...I have some rotors...but no hats...by some rotors I mean one...my search continues.....

if there is a supply problem go right to the source...call stoddard...also Atlanta seems to be one of Porsche's hubs for parts...don't know how to contact them though....

[ChrisBennet]

The '78 and '79 930 had floating rotors. If you don't track it, another set should last near forever. I think I paid a little less than $250 each last year for some.
-Chris

[E Ray]

Hey Chris where did you find them? When I find someone with a decent price the only have the left side, go figure, someone out there buying up all the rights? Let me know, 250 a side I can kinda live with that.

Thanks

Eric

[AES]

There are a lot of threads about the early/late 930 rotors, here's just one,

930 rotor thread

You can do a search on Bill Verburg, as he has posted in most of them.

[Bill Verburg]

The '78-80 930 used a 3 piece rotor setup consisting of a floating 304x32 mm rotor, a flange and a ring, all held together by 6 mm bolts. A separate 21mm spacer is used to give the hub the correct offset to fill the 9" 930 front flares. The mod to the new style 1 piece nonfloating 304x32 mm rotor(std from 81 model yr on) simply consisted of a new 911 style hub , the new rotor attached with 8mm bolts(as with a 911SC), and different grease caps. With this setup the 3 piece rotor and 21mm spacer are discarded(I would like them and be willing to pay reasonable shipping, if you are just going to throw them away). The spacers are no longer needed because the 21 mm offset is incorporated into the rotor itself.

To do this change you need 911 hubs and 8mm bolts(76 up work fine) and the new rotors, everything will bolt up nicely. Thom Fitzpatrick(Widebody) has recently bolted the 1 piece rotors & 930 calipers to his 911 and posted a lot of pics and discriptive text which I can't find just this minute. You'll have to do a search on user name 'Widebody'

[E Ray]

Bill:

Let me get this straight, if I get ahold of a set of '76 or newer 911 hubs the '81 to '89 turbo rotors will bolt right up and I will not need the wheel spacers, right? I was under the impression the 930 hubs were unique from 911s due to track width etc.?

Thanks

Eric

[widebody911]

Here's the link:
http://vintagebus.com/howto/brakes/front/

The later hub et al just bolts right up.

[Bill Verburg]

Thanks Thom!
E Ray, Actually all of the 911 hubs from '74 on will work. Believe it or not the biggest issue is the grease caps, there are 4 different versions.

The only difference in hubs (besides the grease caps) was the 6mm bolts used for the floating rotors and 8mm for others, the 930 track was widened by 21mm/side by using the separate 21mm spacers in '78-80 and the 21 mm offset rotor from '81 on. You will not want to, nor be able to, use the separate spacers with the new 1 piece rotors.

[E Ray]

Great info guys, thanks a million.
Now it off on a search for some '74+ hubs, the rotors are the easy part.


Thanks again

Eric

[Bill Verburg]

The hubs should also be easily acquired at any recycler, as usual newer is prefered.