911SC Caliper Questions
 

Howdy, I am interloping from the 924/44/68 forum, and have a couple of quick questions.

1. What is the mounting bolt spacing on these units?
2. Are there seals between the halves? If so, are they included in rebuild kits?
3. If there are seals between the halves, do you think they would withstand the heat of the powdercoating process?

Thanks!


rasta

I'm sure you have to break down the callapers to powdercoat them. the seals ar not included in the kit and are hard to find. you can blast them and use callaper paint or VHT but not the same as powdercoating. not sure on the spacing

3.5" spacing on the A and wide A calipers.
Rubber seal are between the halves and the spacers, and are not included in the rebuild kits. They may survive the heat of the bake oven, but I would not risk it myself.
I'm not a fan of powdercoating calipers.

Rats, thought I had this figured out. Which 911 caliper has 3" bolt spacing?

M calipers, for one. Maybe S?

All of the M calipers

Hrm, can anyone summarize the sources of, and differences between "M" calipers?

TIA, I know total nOObs can be frustrating!

Brakes

The A-type and S-type calipers use the 3.5" mount spacing. S-type came out in 1968, were aluminum, and were suited for the 20mm vented rotors. Last used on the early turbo. The A-type is cast iron, and was a less expensive alternative but much heavier. The wide A-type was used with the wider 24mm vented rotors, and used a spacer. Both A & S used 48mm pistons, both used the same area pads, but the S used thicker pads; the late 908 variant of the S caliper used even thicker pads.

The M-type calipers came on the 1965 911 with 3.0" mount spacing. The M-type calipers came in several versions, both front and rear type, both un-vented and vented widths, 38, 42, and 48mm piston sizes, and also 3 different casting types/sizes. 911 & 912 fronts were 48mm pistons in large casting with back side banjo connection line inlet. Vented rotors appeared on the 1967 911S and were optional on other models; these calipers had 7mm spacers. The 1970 914/4 used a small casting with back side banjo connection line inlet, and 42mm pistons. The rear 911/912 calipers from 1968 on were the same small casting, with a bottom line inlet (no banjo), and with 38mm pistons. When used with vented rotors these calipers had 10mm spacers. From very late 1972 the 914/4 used a larger casting, 42mm pistons, and a back side line inlet without banjo, and dual bleed nipples; these used thicker pads than the early 914/4 and 911 rear calipers. All 914/4 front calipers were VW cast, and used a pinch collar on the pins to hold in place; they also used anti-rotation device on the pistons. The 911/912 calipers used a wire clip through the pin to secure in place.
From 1965 through 1967 the 911/912 rear calipers were the L-type with about 2.25" mount spacing (smaller bolt size also), individual bleed nipples for each half of the caliper and cross-over line (like the S-type caliper). There were two types: 35mm pistons in the normal caliper and 38mm pistons in the wide L-type used on the 911S (with spacers to widen the caliper.

Actually the L, M, and S most accurately defines the area of the brake pads used. The L used the smallest pads, the M used the mid sized pads and the S & A used the largest area pads.