Brake Caliper question - Calling Bill Verburg

[Dan in Pasadena]

A year and a half ago I bought these calipers from Pelican Syncroid (he is a good guy):






The text of his original ad read: :

"These came off of a 1985 Carrera. They have been rebuilt with Ate rebuild kits. Pads are Axis (Repco D-552 deluxe) Spring retainers are new as well. $200.00 for the pair plus shipping."

I paid the asking price buying them for my '76. Per an email with Bill Verbug my understanding was they would install with no problem using Carrera rotors.....they didn't. Since we all know Bill knows what he's talking about I think fair to guess they are not Carrera calipers, so what are they? Must be earlier car calipers?

Nevertheless, they are freshly rebuilt and perfect. Now I need to sell them as I went with rebuilding my original calipers because of time constraints. I am open to offers but don't know what they are and so don't know the going price.

Advice needed: Just measure the distance between mounting holes and if it is 3" they are ...what? Shouldn't my Middy (and SC's and Carrera's) all have 3.5" bolt spacing? Other possibilities?

[vash]

i am not sure, but i thought the carrera calipers will fit on the SC's, and not the midyears. something about a 3 vs. 3.5 in spacing. i paid $400 for a set from partsheaven. and mine needed to be rebuilt. yours look great! (i am feeling a bit RIPPED!)

edit: my money may have included new rotors...i cant remember

[Bill Verburg]

All M are 3" and all A & S are 3.5"

What specifically didn't fit? bolts, rotor?

[cmcfaul]

Look like M's to me

Chris

73 911 E

[Bill Verburg]

all the rears are 3" M,

3" M, 3.5" A and S have been used on the front depending on year and model

starting in '84 they were all widened by 4mm but still use the same mounts

[Dan in Pasadena]

Hi Bill, thanks for answering so fast.

I was in a bind for time and at the last minute took my car to a shop and asked them to install these for me. They called to tell me they wouldn't fit on the rotors. I tld them to use Carrera rotors. They did and still wouldn't fit. In frustration, I told them to just install rebuilt stock calipers - keeping in mind your advice that these would only give me greater heat dissipation because of the rotor size rather than more true stopping power) Yes, before anyone chimes in, I know greater dissipation DOES give me more stopping power in a way because I can get on the brakes harder or stay on them longer. Anyway, I went with stock. Turned out I had two frozen pistons so to say the improvement in my braking was DRASTIC is a giant understatement. When I get home tonight I will measure the bolt spacing and look for any other indicators you tell me. I am now wondering if the shop (I used them on advice of a friend, not my usual shop) mistakenly tried to fit them to Middy or SC rotors or some other snafu. If they really ARE Carrera calipers then per Vash's note, they would be a great deal for someone. I will pass them along to anthoer Pelican. Bill, anything other than bolt spacing or markings I should look for? Need me to take a better picture of something? Thanks, you are a real asset to us on the board, Dan

[Bill Verburg]

They sure do look like M, can't tell whether they are the wide M or not.

Assuming that they are as advertised they go on the back w/ '84-'89 Carrera rotors.

They should fit fine

Did you shop try to mount them in front?

[Eric_Shea]

They are not M-Calipers. Those are A-Calipers. You can tell by the peak at the back of the caliper where the fluid inlet is. They could very well be the Carrera calipers he mentioned (they're the same for that year with the exception of the width of the spacers).

Now, they may not have fit on the rotors due to spacing with the 76 hub. You may have to mill 2mm off the backside of the hub. The hubs usually make up 1/2 the distance of the spacers (if this makes sense).

Hope that helps.

[Bill Verburg]

Originally posted by Eric_Shea
They are not M-Calipers. Those are A-Calipers. You can tell by the peak at the back of the caliper where the fluid inlet is. They could very well be the Carrera calipers he mentioned (they're the same for that year with the exception of the width of the spacers).

Now, they may not have fit on the rotors due to spacing with the 76 hub. You may have to mill 2mm off the backside of the hub. The hubs usually make up 1/2 the distance of the spacers (if this makes sense).

Hope that helps.

Now that I look more carefully I agree, the A's feed into the center and the M's feed into the ends

A on left, M or right

[Eric_Shea]

Rear M-Calipers feed into the ends. Front M-Calipers feed into the side.

[Eric_Shea]

Here's a "front" M-Caliper.

[Bill Verburg]

I'll take your word for it, I haven't seen a front M in 30yrs

All of the rear hubs are the same from '74 to '89

[Eric_Shea]

All of the rear hubs are the same from '74 to '89

Correct... but I'm assuming he's having a problem with his fronts.

I'm taking a stab at the front hub because They changed the rotor mounting surface each time they changed the width of the spacer. The first spaced M-Calipers necessitated that mounting surface be move out by 3.5mm (???) or 1/2 the distance of the new 7mm spacers. You can see this by putting a 66 hub on the table next to a 71 hub.

The A-Caliper should be the same... once it got wider spacers and became the "Carrera" caliper I'm guessing that 1/2 the distance of that new, wider spacer had to be milled off the rotor mounting surface on the hub. There would be no sense in manufacturing a new caliper for this offset as A-Calipers are quite common on Mercedes, Volva's and various BMW's of the era.

So, I'd say those may very well be Carrera calipers (A-Calipers with the larger spacers) but the hub is incorrect for the application. If Dan can find some Carrera hubs they will probably bolt right up. Or... if he could measure the delta, he could mill those hubs.

HOWEVER... Hard to tell from the pictures but those spacers look aweful thin to be Carrera calipers. :O

Hope that helps.

[Bill Verburg]

Front hubs are also the same from '74 - '89

[Eric_Shea]

Hmmmmmmmmm... there's a puzzle then.

I'd go back to the shop then. Guessing (as someone mentioned) they had the wrong rotors because if the hubs are the same, the rotor offset changed. Should be a bolt and go.

Dan... what calipers came on the car?

[Dan in Pasadena]

Gee, I stepped away from the computer for a while and a lot of conversation went on!

Eric, the calipers that came on the car are stock mid year calipers....I don't know what they're called.

Bill, yes the shop DID try to install them on the front; my intent wasthe larger Carrera rotors (and of course corresponding calipers) on the front and the stock Mid Year rear rotors/calipers. Per the PM you sent me Bill, that can be done without a proprotioning valve or other mods.
It was my understadning (perhaps wrongly so) that they would fit the front with only the Carerra rotors.

Botomline, I can't sort out al the various opinions expressed. Are they A calipers? I THINK I am reading that A's and "Carrera" calipers are one in the same? But they are rears for a Carrera? Or am I misunderstanding? I just need to sell them but don't know what to call them. I don't want to lead someone the wrong way. Again, I'll measure the bolt spacing an post it. What else do you guys need to tell?

[Bill Verburg]

Yes, they appear to be wide '84 - '89 Carrera wide A fronts and yes they should bolt up w/ 24mm '84 - '89 Carrera front rotors, I can't imagine what problem your shop had. This is a common upgrade on many cars. As long as you have 3.5" mounts on the struts.

Not all '76 have 3.5" struts, some did come w/ 3" struts and front M calipers

[Dan in Pasadena]

Ok, sounds like I should first measure the bolt spacing on these. If they are 3.5" then they are as advertised - '85 Carrera front calipers. So I can advertise them as "84-'89 Carrera wide A front calipers"? You feel it is accurate to advertise them as this description?

I can't measure my hubs today, but it sounds like the reason they didn't fit can only be one of two: The shop tried to use non Carrera rotors, or my '76 hubs don't have 3.5" spacing. Have I got this right?

[JP911]

I think the Boge struts (black housing) with 3" spacing were a part of the base suspension setup on the mid-years. My 76 had the Koni struts (red housing), which have 3.5" spacing and readily accepted the Carrera front brake upgrade.

[Bill Verburg]

Originally posted by Dan in Pasadena
it sounds like the reason they didn't fit can only be one of two: The shop tried to use non Carrera rotors, or my '76 hubs don't have 3.5" spacing. Have I got this right?

Yes, I suspect that your car has 3" struts