L-Caliper Identification Thread

[Neunelfer]

As promised in another thread, I wanted to give everyone a look at the very early 911 and 911S rear calipers. This will show the (fairly drastic) differences between the standard 911 rear caliper of the day and the first 911S rear caliper.

I get the question often; can I add some spacers to L-Calipers and make them the 911S Wide L-Caliper. The simple answer is no. For those so inclined to be bored by caliper minutia... read on. Others; continue searching for ye orange hood badges and $50.00 tool kits.

First the Wide L-Caliper S group:



Next the standard 911 L-Caliper:


First we'll look at the bore for a standard 35mm L-Caliper:


Next... the Wide L-Caliper for the 911S. This is the first 911 rear caliper to receive a 38mm piston. They stayed that way until 1983!:


How they got that way is a different story, they simply bored out the L-Caliper for the larger piston. This left a smaller collar for the Wide L-Caliper dust boot. This means you have to be very careful when restoring a vintage 911S Caliper. Here's the standard L-Caliper:


And here's the Wide L-Caliper:


Fasteners tell another story. With the jump to larger pistons, also came the jump to M7 fasteners. The first L-Caliper came with M6 hex head fasteners with 10mm bolts. The Wide L-Caliper came with M7 Ribe hardware:

Wide L-Caliper:


Standard L-Caliper:

[Neunelfer]

Another thing to note are the fluid inlets.

The Wide L-Caliper has a strange, almost cam-lobe apearance around the fluid inlet:


The standard L-Caliper has a fairly normal inlet:


Oddities from ATEland?... how about an upside down logo and casting marking on a Wide L-Caliper?:


The nose section of a Wide L-Caliper is rather brutish compared to it's L-Caliper brotheren:


The L-Caliper looks a bit more "refined":


Finally... one of the biggest differences from the L-Caliper and the Wide L-Caliper is the things that make them wide; these 10mm spacers!:


All in all, it would take a ton of work and money to convert an L-Caliper to a Wide L-Caliper, even then you wouldn't have a correct version. There's simply too many differences to make it worth while.

Hope this helps.

E.

[preS]

Eric thanks for this detailed report.

Richard

[Alan.uk]

Great info, thanks for posting the pics.

Alan

[Neunelfer]

Well, this will about wrap it up. I'll post some final pictures of some differences in fasteners and show some finished pics:

First off are the standard 911 L-Caliper fasteners. These are M6 hex cap fasteners with 10mm nuts. The have a ribbed top and a standard 5mm hex head. The originals have been black oxide treated:


Next are the Wide L-Caliper M7 fasteners. These were manufactured by the Ribe company and have R6 heads and 11mm nuts. Again, originals have been black oxide treated as these are NLA:


Here's a gander at the finished L-Calipers. Outside appearance notes; Hex cap fasteners and no spacers:


And the finished Wide L-Caliper, vintage 911S models. Outside appearance notes; obviously, the 10mm spacers, R6 Ribe cap fasteners:


The two lined up so you can see the spacers and the rotor gap:


And finally, the front M-Calipers that go with the standard L-Caliper rears. Notice, no 7mm spacers in these:


Richard, enjoy. We're getting your Wide M-Caliper front fasteners re-done to match the rears this week. They were originally yellow zinc. Little touch but I tought you might like it.