I just pulled this from a page that redshift sent me to HERE. How is this done?
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The rear of the car received the following:

Widened stock calipers for use with vented rear rotors
Resized (smaller OD) 911 rear vented rotors (cross-drilled and slotted)

Hey, I know this one!

You know how the rebuild kits *don't* come with the center gasket?

You need 2 of those gaskets, and the spacer (There is a factory part.. #? or have one machined) I think it's like 7mm?

You split the caliper, add the spacer, and thar she blows. Vented is much more useful than drilled.

I'd also like to point out that, as stated later in the article,"Brad Robert's came to my rescue with an '80 SC 915 core transmission."...

I am in a tower dungeon, I need a 4.0/6, with a wild one-off MFI setup Brad! Save me!



M

and you still use the rear ebrake right?...im doing a 5 lugg swap in winter- this could be my cup of tea....
more info plz. what rotors? where do i get the spacer, and the rebuild kit?

I think the only set I have seen had spacers that were machined out of another caliper... 911? I am searching for a page I saw with all the parts laid out, someone is just about to do this again... I'll see..

Crapola... I have no luck so far..


M

So.. tell me WHY you need vented rear rotors ??

Nobody on this BBS NEEDS vented rear rotors...


Oh.. and yes.. Rich Johnson, Richard Fischer and I have been friends for many years...

I actually shot the pic they used for that site in 1999 at the MUSR in Hot Springs.



B

Brad.. bling comes in many forms, to some it's a 30" wheel, with fake plating, that spins all the time.. some women like to stuff their chests with unnatural materials so they can look like a transvestite... I mean Pam Anderson..



M

Well I think my setup has vented rotors for cost, for the 5 lug conversion..

Which would you rather pick, a simple cheap spacer and put a vented rotor..

Or spend the cash to get the stock rotors drilled out..


I know which one I would use..

Just my thoughts...

Andrew

Um.. stock 9146 /early 911 solid rear rotors work fine with a stock 914 caliper. They also are cheaper than a 911 vented rear rotor (new).



B

The spacers are not a easy as they are made out to be. If I recall correctly... you need O-rings which are semi difficult to come by.


B

1st... I want to say I agree with brad.
I sold my rear vented rotors and on the new car I will be running non-vented 914-6 rear rotors...

2nd, I've done the rear vented rotor twice... with 2 different ways. (Remember I sold both of them).

If you want to re-use a stock rear caliper:
you will need to buy original square O-rings (dealer type item) Also you will need all new hardware as in longer (vented) pad retainer pins, and springs. Also, the bolts that hold the caliper halfs together will need to be longer. I would suggest that you buy a complete core set of M-calipers in order to steal these bolts from. Finally, what I did was machine spacer blocks of the appropriate width from steel stock. After I had gotten them close, I took to a machine shop and had them surfaced and had the fluid passages cut. This is where the O-ring goes and there MUST be a square shoulder (like stock) inside of the passage for the square O-ring.

Next, buy 911 rear vented disks. They need to have the outside diameter turned down just a little bit for clearance. I sent my notes to the guy whom I sold mine to and don't have the exact figure any more. Just dry mount the calipers and you will be able to tell, Its not a lot, I think around 3/16. I had the same machine shop do the rotors.

My other set of vented rear used a 914 front caliper but spaced. For this application you do not need to make the spacing block from scratch and you can just use the spacing block out of the core M-calipers you buy. I was able to just leave the same rotors on the back... and do not know if you would have to turn them down this way.... This technique is easier but you do loose the parking brakes.

Warning.. this adds a lot of sprung weight.
I believe this would be appropriate for a high downforce, full slick car. I think it is actually detrimental to a small track car or combination DE/street car.

brant

Alright Brad, I didnt know the 911's had a solid rear rotor (Shows how much I know !), But I Think the spacers in the A calipers fit.. I have a set of spacers on my bench and a set of rear 914 calipers with spacers on the car.

I knew there was a reason that you guys wherent talking about that... Oh well, learn something new every day!

Andrew

Thanks Brant..

I'll run out today and get 10,000 sets made....LOL

PAIN IN THE ASS FOR LITTLE/NO RETURN.

Spend time/money elsewhere.


B

I want to say that I disagree with Brad.....Ohmygawd.

I need vented rear rotors. With S front calipers, I needed M rears to get in balance. Thus I needed vented rotors. I could not get enuff rear brake with the 914 rears....they were just along for the ride.
Puting 914 fronts on the rear *might* have worked, but I knew the Ms would, so I skipped that step.

BTW, I run my porp valve wide open....I kinda crept up on it, tho.
Front to rear balance is very nice, now... for AX. Heavy trail braking causes the back end to step out just a tad.....yee haw.

Different "issue" JP.

Your not trying to do something that is worthless when your done.

They are not trying to go to a larger caliper.... they are trying to run vented rotors with a stock caliper.

I say "its not worth the effort" run solid 9146/911 rear disks and keep your ebrake.

Balanced braking is a must.. you nailed a good combo.


B

OK, so I missed your point.

IMO, the balance issue is all important...for what I do.
Any time one starts screwing around with brakes,
unintended consenquences can pop up and, as you have said, some are a waste of time, effort, and money.

Some, while not unsafe, detract from the performance of the car......the Volvo front calipers come to mind.....lotta weight, what's the return?

The stock 914-914/6 brakes are decent...not great, but decent. A step up....if you think it's needed, should be done as a whole package....something it took me a while to learn.

I didn't mean to get everyone riled up.

I just thought a vented rear sounded interesting!

Hey, we know how to get Brad's goat!




M