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Inspired by this article:

http://www.pelicanparts.com/techarticle ... lipers.htm

If it works that well for 914's, it surely must do s/th for the 412
Anyways, as locating a pair of rebuild 320 calipers was way more easy than for a 412, I located these and fitted them:





You can also see the bmw spring in addition to the bmw caliper..

Funny thing is that the pelican article mentions that the LATE 914 models have slightly different spindles, which neccesitated modification of the bmw caliper by milling of some material of the 'ears' of the bmw caliper.
Now, I had to have that done as well!!
So that would conclude that the late 412 seems to have more in common, caliper and spindle-wise, with the late (post '72) 914 than the early 914 ('70-'72)...
Just an observation.

The bmw caliper may be a nice upgrade if the 944 rear disk brake works out (Bill, take notice haha!)...

I haven't driven with the set-up as is (stock rear drums, but with about 1mm bigger wheel cylinder: 23mm superbeetle) yet, but I already know that the skinny 155 tires will not be up to it

Regards,
Walter

Yes, that is correct, The late 914 and 412...that would be after August of 72 share the same spindle dimensions, caliper and rotor. The early 914 and 411, share the same spindle dimensions caliper and rotor.

Which rotor is that in teh picture. It appears to be the early 914/411 rotor as it does not have the raised strengthening ring around the hub....or it does and I just can't see it because of the centercap.Ray

Good to see another T4 nut going after a brake upgrade. I've got a set of those BMW calipers in the attic waiting for me to get unbusy to have them machined and installed. Keep us posted on your progress.

raygreenwood wrote: Which rotor is that in teh picture. It appears to be the early 914/411 rotor as it does not have the raised strengthening ring around the hub....or it does and I just can't see it because of the centercap.Ray

It is a new one from an old stock of s/body and the same model as the one that came off, so it should be a late one. It has a raised ring for centering. I suppose it is strengthening as well.

Yes. That ring is very important. It makes the late rotor much stiffer. It allowed the use of the late model caliper with thicker pads and without the centering pin and clutch inbside of the piston chamber that the late type 3 used. That mechanism, is probably what caused the type 3 version of the caliper to be manufactured in a smaller width all around.

Its hard to say wether the ring itself gave a good deal more stifness...or wether the ring fitting into the middle of the wheel effectively "triangulated" the wheel and rotor into one more ridgid assembly. Ray

How does the brake pads fit to the brake disc? I mean, does the diameter of the brake disc reach brake pads fully when assembled.

func412 wrote:How does the brake pads fit to the brake disc? I mean, does the diameter of the brake disc reach brake pads fully when assembled.

I think it fits better, as the pad now covers the 'whole' width of the disk, maybe 0,5-1,0 mm over the edge, which is no concern. The original pad left appr. 2mm on each side untouched.

raygreenwood wrote: Its hard to say wether the ring itself gave a good deal more stifness...or wether the ring fitting into the middle of the wheel effectively "triangulated" the wheel and rotor into one more ridgid assembly. Ray

I think vw discovered, as did Porsche, that especially at the front, a well balanced wheel is essential and hub-centering is the most efficient way to achief this. Porsche uses hub-centering also for the rear wheels

I'm sure that was a big plus for the centering ring as well. The 412 stayed better balanced than my 411..But I do know that the main purpose of the extra ring on that particular rotor was to counter flexing. Its in the factory literature. I'm just not sure if it accomplished it through just the strategic addition of more metal in the ring....or the bracing is gave with the wheel.Ray

Ok, I thought VW made the rotor stronger by making them thicker for the 412 as they went from 10 mm to 11 mm.
A thicker disk does more against warping imho.

Reagrds,
Walter

Yes, that is correct also. The late rotor was better in all dimensions than the early one. The caliper was better....and the pads were thicker. Ray