In the process of restoring my 914/6, I want to have vented rear rotors, mostly because I'm going to have a big engine, but also because I think it's kinda cool.

The stash of parts I bought from Jon Lowe contained some rebuilt original 914/6 rear calipers.

It also contained some good condition 911 front calipers "A" calipers I think: 3 inch bolt spacing, steel, and with a spacer. They had 48 mm pistons.

To build rear calipers that have a spacer, there is one recipe that uses the spacers from the rear of 911 mid-year calipers, as well as other hardware. Those spacers are 10 mm. I don,t have such calipers and initial attempts at getting some were unfruitlful.

So, I took the spacers from the front calipers that I have, but they're 7.5 mm thick.

I figured it might be easier to simply add a second thin spacer, rather than build a thicker one. Not sure it's going to be the final solution, but I had the thin stock handy. This is really a test piece:

and:

A calipers are 3.5" spacing (and made of steel).

If you have 3" spacing calipers that are on vented rotors they are probably M-calipers.

and bolted up.

As far as I'm able to measure, the two spacers clamped together end up being 10.3 mm thick. Close enough.

I still need to find some 7mm bolts that are 70 mm long. There's a good hardware store that I use, in town, but they did'nt have any in stock. Apparently they can get me some, in socket head format.

Also, the spacers have 8mm holes in them, but the 914-6 rear caliper uses 7 mm hardware, as noted above. Does anybody know the hole size in the spacers for the mid-year rear 911 calipers ?

Couple more things I will need will be the little rubber O-rings and the retainer spring.

Finally I'll need to turn some longer pad retaining pins. It's a very simple turning and should not be a problem.

Not sure what I'll end up doing. Stay tuned.

Michel Richard

QUOTE (fiid @ Jan 15 2006, 06:41 PM)

A calipers are 3.5" spacing (and made of steel). If you have 3" spacing calipers that are on vented rotors they are probably M-calipers.

They're M calipers, then. Thank you.

Michel...

Just do it right...

Rear 911 calipers are a dime a dozen. Years 70-84 oughta do the trick (not too many years to choose from). 6 o-rings per caliper? Hours fiddling with 2.8mm spacers? You should be able to find a core set for $50-70 bucks... what's your time worth? Also, 7mm hardware will be difficult (unless you get the $50.00 core 911 rear brakes, in which you can use that hardware and it's a perfect match to the hardware that was on your $1000.00 calipers!), so now your talking hardware store hardware for 914-6/GT calipers?

This is a serious car your putting together, those are some of the most sought after brakes in 914dom. I'd hate to see you move forward with that concoction, especially on something as important as 'brakes'. Please someone, send this man some toasted rear M-Calipers.

(sorry... I hope I don't offend. It's just my $0.02 and sometimes I don't know when to shut up)

E.

Forgot...

QUOTE

Does anybody know the hole size in the spacers for the mid-year rear 911 calipers ?

Yes... but I'm not going to tell you

QUOTE

Couple more things I will need will be the little rubber O-rings and the retainer spring.

I stock both, but the o-rings only ship in 8 packs!!

QUOTE

Not sure what I'll end up doing. Stay tuned.

My prayer for you little buddy

Dear God, please help guide Michel through these troubled times. Please help him make the right decisions for his bare tub 914-6 restoration. Please help him see the value in his 914-6/GT calipers and the wisdom of the ATE engineers. If he does go to the hardware store to get fasteners please make sure it's 11.8 and it won't sheer under pressure sending him plumeting down some remote Canadian mountainside. Please watch over our little friend to the North. Amen.

Amen

Eric,

okay, okay, I'll do it right. I got your point, and you're correct.

Michel

Michel

I think I have the spacers and pins you need. I will check in the tomorrow. Send me an email of evrything you need though.

Brian,

Email sent.

Cheers

Has anyone ever checked to see if the parts from a Ferrari 308 would work? They are suppose to be the same caliper from ATE.

As I understand it, it's the Ferrari guys who come and raid our calipers and parts, not the other way around. Ferrari parts are even more expensive than ours.

Yeah Michel!!

Yeah Brian!!

You probably don't have the pins, they have to be custom made with the one large pin diameter (one pair may work). Spacers and hardware would be the ticket, also, the 911 pad springs will also be needed.

Paul,

Those are the exact same caliper with one difference, the bleeders are 180 degrees oppositie the 914-6/GT caliper.

Eric,

Did all 911 rear calipers, in 1976, have the spacer ? i.e. did all 911s have ventred rear rotors ?

Because I just bid on a pair on ebay and I could'nt tell in the picture. Did not reach reserve, but I'll still try to buy them.

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...TRK%3AMEDW%3AIT

Michel

Those are exactly what you need.

Yes, they have the 10mm spacers.

So where did you find 11.5 grade m7 hardware? I searched and searched, but couldn't find any.

This place list 7mm hardware

http://www.aaronsmetricscrews.com/default.htm

QUOTE (9146986 @ Jan 16 2006, 11:30 AM)

So where did you find 11.5 grade m7 hardware? I searched and searched, but couldn't find any.

Perry,

Have'nt actually found the hardware yet. The clerck at the store said they could get it, but I have'nt seen it, I should have confirmation within a few days. These would be hex socket head cap bolts (whatever they're called), and all of those, around here at least, are grade 12.

It's Quincaillerie Notre-Dame, on Notre-Dame street West, in Montreal.

Michel

Michel,

I found the spacers,pins, and bolts I have. They are 14mm spacers. Let me know if you still want them.

..

Hmm, 14mm spacers would work for the later 24mm vented rotors.

I have a 914/6 coversion which has the 911 vented calipers in the rear. I got a set of spacers a long time ago from Stephens Maching that allowed the use of the stock 914 rear caliper.

When using the 911 vented caliper you will also have to turn down the diameter of the disc to fit the caliper regardless of which you use.

If you can get those m7 in a socket head, which is a hex socket head, that's cool too, probably better. I'd be good for a few sets of 8.

QUOTE (9146986 @ Jan 16 2006, 05:47 PM)

If you can get those m7 in a socket head, which is a hex socket head, that's cool too, probably better. I'd be good for a few sets of 8.

Perry,

In view of everybody's comments, saying they are so rare, if the store comes through, I may just buy a box of 100, and make it available to the list. Let's keep our fingers crossed.

Michel

Ok,
I decided to do something a little productive. I was thinking about Eric a couple of times while doing this.

I decided to turn some pad retaining pins. I got one done. I find it's very difficult to take a picture of a piece spinning in a lathe, but here it is.

Please be gentle with me if you're going to critique my machining technique. All I know is it results in a pin. Longer just-machined pin next to stock one. Small transverse hole still to be drilled.

Brian,

Thank you for looking.
I will try to find the proper 10 mm spacers first. But please keep in touch.
Cheers,

Michel

QUOTE

Please be gentle with me if you're going to critique my machining technique.

Awesome

Make me some

One thing you may want to consider... machine the bumps off. I don't think any of the pads come with the larger hole anymore. Leave the large one in the back but the ones that support the pads can probably safely go bye-bye. If you don't you'll have to drill out the hole on the pads (which is easy as well).

QUOTE

Brian, Thank you for looking. I will try to find the proper 10 mm spacers first. But please keep in touch. Cheers, Michel

No problem. Back to the box they go.

Michel,

Jimmy Wilkerson made the spacers for my calipers. I believe he still have complete sets of spacers for 914-6 calipers as well as 914-4 calipers.

His e-mail address is Gemi283@webtv.net

Two things,

1) The hardware store called and they say they can't get any 7mm socket head bolts, any length. I asked if they could get Torx head, or other similar, and apparently not. Oh well.,

2) finished making the pins:

And this is how they will look when installed. Eric, the additional 2.8 mm spacers are there only for mock-up purposes. I will get proper 10 mm spacers.

QUOTE (rickyhgarcia @ Jan 16 2006, 08:32 PM)

Michel, Jimmy Wilkerson made the spacers for my calipers. I believe he still have complete sets of spacers for 914-6 calipers as well as 914-4 calipers. His e-mail address is Gemi283@webtv.net

Ricky,

Thanks for the tip. I'm realizing that the hard part will be to find the bolts. I can probably make 10 mm spacers myself, but I will certainly keep Jimmy's email handy.

Cheers.

Michel

why don't you just order one of Eric's kits?

QUOTE (Jeroen @ Jan 17 2006, 07:33 PM)

why don't you just order one of Eric's kits?

I did speak to Eric about that, but I have original /6 calipers and I don't think his standard kit would help me. He was generous and made suggestions as to what I needed to organize, though.

Michel

really? is putting vented rotors on /6 calipers different than /4's? dont wanna hear that.

Some 911 caliper bolts are available from Porsche. I guess I'd look at sourcing the next size OEM, and drilling and tapping.

I've done a ton of research into the 308/914-6 caliper connection. Let me know if you have any questions regarding that.

Nice pins, BTW.

McMaster car sells M7 bolts, if that helps.

Just looked at the McMaster Carr website. They do have 7mm hardware, but not socket head cap screws, at all, and not standard hex head in anything above 50 mm.

It looks like the closest they have is 8mm by 70mm. That would probably mean drilling the bolt holes in the caliper oversisze, and I don't want to do that to my unobtanium 914/6 calipers unless there is zero other choice.

The other alternative is to use the hardware off of core 911 calipers.

Michel

I've been working on both conversions for about 6 years. Pins and spacers are different between the /4 and /6 calipers. Bolts are only available from core 911 calipers or if I have them custom made in the UK. Well, okay, I could get them made here for $14 each (minimum 50). They are grade 9.8, and the only others I could find were grade 8, and half the tensile strength. If there is sufficient interest I could place the order for the 100 minimum in the UK.

CODE

why don't you just order one of Eric's kits?

-4 and -6 calipers are different.

QUOTE

I guess I'd look at sourcing the next size OEM, and drilling and tapping.

OMG!! On 914-6 calipers?

It's really simple gang... get some core 'Rear 911 M-Calipers' Virtually everything you need is simply 'there'. Here's what it takes to do this conversion (detailed list)

*10mm Caliper Spacers (included, exact match in the rear 911 m-caliper)
*Longer Hardware (included, exact match in the rear 911 m-caliper)
*5mm Rotor Spacer (we can supply, they're not cheap but not too bad)
*Custom Pins (Michel has this sorted... for others plan on about $12-15 each at a decent machine shop)
*911 Rear Pad Spring Kit
*Longer Studs for the rear hubs (to accomodate the rotor spacer)

Now, consider how much it costs to get my V-Caliper kit, and I'm not raping anyone here... a pair of core 911 M-Calipers should go for $40-70 bucks. Think about it... $40-70 for 4 correct spacer and 8 correct bolts.

No brainer... it would be worth $100 or more to me if I wanted to do this to a -6 caliper.

I agree with Eric. Find some junk 911 rear calipers. I've stripped about 10 calipers so far. Perhaps someone in California can raid a yard or two for us. Not too many left to raid in Utah or Ontario. Give Eric and myself a note if you can help.

I phoned Parts Heaven and talked to Jeff. He agreed to take core calipers apart and to ship just the spacers and the bolts. US$ 40 !
I'll report when they arrive.
I then use regular 911 rear vented rotors, right ? If memory serves, the only thing that might happen is the need to turn down the outer diameter a couple of mm.
If all works out well in that area, the plan is to get spreader springs, the rotor spacers and longer studs from Eric.

Turn the 911 rear rotor down to 286mm from 290mm.
I know it is not much but the extra weight and unused surface is detrimental. Also provides the needed clearance.

I figured out that the pins that I made with the bosses were not ideal.
It looks like part of the job of those pins is to help center the spreader spring. So I turned another pair with a shorter mid-section.
Here's a picture of an orginal short pin (bottom) my first attempt (middle) and this morning's style of pin. This morning, I made the bosses longer and the mid-part the same length as on the original.

And here's what the new pin looks like in the caliper. Once more, the spacers betwen the caliper halves in this picture are for mock-up purposes only.

Got my spacers and bolts from Parts Heaven, and I'm pretty happy.
Here's what I got, four of these spacers, and eight bolts: