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Mon Sep 28, 2020 1:18 pm

I'll dig out my Elfrink Type 3 book, which gives a little more info about this compensation pin than Bentley. The latter implies the pin is still in later calipers. Stay tuned...

Mon Sep 28, 2020 5:10 pm

KTPhil wrote: I'll dig out my Elfrink Type 3 book, which gives a little more info about this compensation pin than Bentley. The latter implies the pin is still in later calipers. Stay tuned...

Yep.....there may have been a few cars here and there between about August and December ber of 72 that still used the pins....probably just using up calipers....but persinalpy on a 914 or 412...I have never seen a 1973 model year and later with the pins.

The Bentley I agree...implies that nothing changed after 1972. It also has the same issue with TVS adjusting as well. It assumes not much changed....when it does. Ray

Mon Sep 28, 2020 10:27 pm

Ok, here we go. First up, Bentley:

Note the quote near the bottom of the right column:
"Each piston is hollow and contains a brake disc deflection compensator. The cylindrical pin for the compensator is permanently fixed in the cylinder end in each caliper housing."

Oddly, though this next page is an exploded view of the early, single-bleeder design, it lacks the pin; perhaps this was a pre-production rendering? Possible, since it has the bleeder mis-located as well.

Next comes the British Autobooks page, whose exploded diagram DOES include the pin:; this is also an early caliper with the single bleeder.

Lastly, here is Elfrink's complete description of the system and theory of operation:

The text implies it was not just the disc that distorted, but the spindle as well, plus loose wheel bearings.

And the final Elfrink page gives the part numbers for the later dual-bleeder design.

There is no mention of deleting the compensation pin design. This could be oversight, but perhaps from the factory they had it, and replacement calipers did not?

Did the bearings change at this time to reduce this problem?

There is no mention of a new piston part number, though if the pin was deleted certainly all that jazz inside the piston would have been deleted, too. But maybe the piston is considered part of the caliper assembly, and therefore could be different? Did VW supply pistons as a replacement part, or just the whole caliper assemblies?

It is also possible Elfrink's appendix for the late design was for an "early late" design and not a "late late" design which may have deleted the compensator?

I find it odd that VW (well, actually probably ATE) chose this complex solution when merely thickening the disc and/or spindle castings, as done later, would have almost certainly been cheaper, and more effective and reliable.

We are closer to a perfect history, but not quite there!

Mon Sep 28, 2020 10:41 pm

Yes..... :D ...that is a mis-rendering in the Bentley! Notice the piston in teh airbrushed rendering....with the raised dimple in the middle....that is only used on pistons that have pns.

Also...notice that all of the rotors in all of those pictures....have no centering ring. They are all earlier than August of 1972...meaning they probably all had pins. The Elfrink manuals were excellent....but you will probably find that they are too early to know what VW changed in August of 1972. Ray

Tue Sep 29, 2020 7:55 am

https://www.jbugs.com/product/16-2526-0.html?rrec=true

dont forget , these are an option now. but unfortunately I havent been able to find specs on the size of the pistons yet, unless Im blind, and I havent gotten off my ass to call wilwood yet.

Tue Sep 29, 2020 7:57 am

I find it odd, that it's been mentioned that the late rotor is thicker (11mm), but when purchasing new earlier style rotors, they are 11mm new.

Tue Sep 29, 2020 9:29 am

Elfrink lists the early discs as 9.5mm, with a wear limit of 8.5mm.
Elfrink lists the late discs as 11mm, with a wear limit of 9.5mm

However, the Autoboooks spec for discs (presumably early) is 9.5 to 9.45mm, with a minimum of 8mm. Ballsy, those Brits!

Bentley agree with the thinner 8mm wear limit on page 2-21, but then lists 8.5mm on page 2-24 when machining, though the same paragraph says replace if under 8mm!

Confused?
;-)

Tue Sep 29, 2020 3:26 pm

KTPhil wrote: Elfrink lists the early discs as 9.5mm, with a wear limit of 8.5mm.
Elfrink lists the late discs as 11mm, with a wear limit of 9.5mm

However, the Autoboooks spec for discs (presumably early) is 9.5 to 9.45mm, with a minimum of 8mm. Ballsy, those Brits!

Bentley agree with the thinner 8mm wear limit on page 2-21, but then lists 8.5mm on page 2-24 when machining, though the same paragraph says replace if under 8mm!

Confused?
;-)

Wear limit of 8mm means worn out = trash. Too thin to use.

You can machine them down to 8.5mm which leaves you .5mm until they reach the wear limit of 8 mm.

However , machining rotors down to 8.5mm and putting new pads on it is a waste of money. Depending on the brake pad material your rotor will reach the wear limit way before your pads are worn.

Sun Jan 03, 2021 10:14 pm

How many different disc spindles made VW ?

The Type3 spindle did change 8/71 from the small bolt pattern to the larger pattern.

Did the 73 model have the same spindles like the 72 or was it different again?

Tue Jan 19, 2021 10:53 am

If I wanted just new stock style calipers and rotors for a 68, where do you guys recommend shopping online? I’ve checked several sites, but it gets confusing for me with all of the conversion sets and manufacturers.

Thanks,
Leo

Tue Jan 19, 2021 1:01 pm

leoasman wrote: If I wanted just new stock style calipers and rotors for a 68, where do you guys recommend shopping online? I’ve checked several sites, but it gets confusing for me with all of the conversion sets and manufacturers.

Thanks,
Leo

AFAIK, at this time, there is no one who sells new or rebuilt type 3 calipers, except for the few members here on Samba that rebuilds them. (Jim Adney for one)

The new calipers you can buy now are really for type 1's. They work and the bolt spacing is the same. But the piston size is 40mm vs the type 3 pistons being 42mm. (or is it 43mm?). That's what the PO on my notch put on my car. But the missing few mm's of piston bothered me, so I bought some used type 3 calipers to rebuild. If the pistons are shot (mine were), it's next to impossible to find new pistons. I luckily found NOS ones, but they were pricey but worth it to me. (It's a safety item, after all.)

If you're handy, you might pick up some used type 3 calipers and rebuild them, with the proviso that the pistons are good. (There's some in the type 3 classified now.)

Rotors you can still buy new. They are the same as the type 1 rotors.

If any of this info is incorrect, the eagle eyed members will correct me. :-)

FWIW.

Tue Jan 19, 2021 3:24 pm

pitargue wrote: leoasman wrote: If I wanted just new stock style calipers and rotors for a 68, where do you guys recommend shopping online? I’ve checked several sites, but it gets confusing for me with all of the conversion sets and manufacturers.

Thanks,
Leo

AFAIK, at this time, there is no one who sells new or rebuilt type 3 calipers, except for the few members here on Samba that rebuilds them. (Jim Adney for one)

The new calipers you can buy now are really for type 1's. They work and the bolt spacing is the same. But the piston size is 40mm vs the type 3 pistons being 42mm. (or is it 43mm?). That's what the PO on my notch put on my car. But the missing few mm's of piston bothered me, so I bought some used type 3 calipers to rebuild. If the pistons are shot (mine were), it's next to impossible to find new pistons. I luckily found NOS ones, but they were pricey but worth it to me. (It's a safety item, after all.)

If you're handy, you might pick up some used type 3 calipers and rebuild them, with the proviso that the pistons are good. (There's some in the type 3 classified now.)

Rotors you can still buy new. They are the same as the type 1 rotors.

If any of this info is incorrect, the eagle eyed members will correct me. :-)

FWIW.

Ok, good info. I have the old calipers, so maybe I’ll contact Jim Aden’s about rebuilding them. I have seen a good thread here about the rebuild process, so that’s an option to try doing it myself. I’ll have to research some more. Thanks!

Mon Mar 01, 2021 1:34 am

In my country where it was impossible to find the replacement caliper, I went for 1978-1983 320i caliper (with 2 bleeders not 1) and they were a perfect fit, no machining needed. Thank you for this thread, it was a life savior.

Mon Mar 01, 2021 8:59 am

bassam wrote: In my country where it was impossible to find the replacement caliper, I went for 1978-1983 320i caliper (with 2 bleeders not 1) and they were a perfect fit, no machining needed. Thank you for this thread, it was a life savior.

Posts like this makes me want to be a hoarder. Already started in a way... :shock:

Mon Mar 01, 2021 3:53 pm

For the late model type 3 caliper....which is the same as early 411/412/914......PMB performance will FULLY rebuild yours. This includes ALL seals including cal8per half seals, hardware, stripping and replating to favtory zinc.

They are probably the vsry best in the business.....short of my own rebuilds..... :wink:

Ray

Tue Mar 02, 2021 2:33 am

bassam wrote: In my country where it was impossible to find the replacement caliper, I went for 1978-1983 320i caliper (with 2 bleeders not 1) and they were a perfect fit, no machining needed. Thank you for this thread, it was a life savior.

Just for the sake of clarity - do the BMW calipers have the 76mm bolt spacing?

Thu May 15, 2025 7:40 am

Just because I have been doing a lot of research into this... i thought i would share. and please anyone who knows better please let me know where i am wrong.

if you have 72-73 spindles , than this wilwood kit becomes an option.

https://wilwood.com/BrakeKits/BrakeKitsProdFront?i...p;option=4

since the late calipers run the same spacing as the 914's, type 3 rotors use the same wheel bearings , and such... this becomes a bolt in modification. you gain vented rotors with traditional 4 lug pattern (if you care to retain 4 lug) with 4 pot calipers braided lines etc... as with everything they are pricey , but in some cases , cheaper than other options out there.

unfortunately since 914 rear arms have their caliper mounts integrated to the arm.. the rear kits isnt bolt in .

this all being said... who has a pair of 73 spindles they wanna sell me? lol