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Thu Apr 23, 2009 7:30 am

I have a 73 fastback, and need new calipers and rotors, i was told at the parts store that its actually a type 4 caliper on the 73s. Is that true? also is it possible to swap rotors and calipers from an earlier model?

Thu Apr 23, 2009 7:54 am

Late Type 3 is the same as Early Type 4. Last I knew, the parts were still available- has this changed? Why would you backdate to something inferior?

Thu Apr 23, 2009 8:23 am

Wrong! I have only seen manuals for the T4, never worked on them, but they say that although the caliper is the same size, and uses the same casting, the Type 3 included the piston return spring device inside the piston and caliper; the Type 4s do not. The pads and I believe the rotor are the same, but the caliper itself is different. The device cannot be removed or added, it is permenantly installed by ATE in their factory.

Thu Apr 23, 2009 8:23 am

If you want to change to the early style, you will have to change the spindles too.
The mounting for the 2 calipers is different.

Thu Apr 23, 2009 8:24 am

I have heard the later ones where simpler to find parts for, and did not get mistaken for type 1 calipers, as the earlies do.

If you have ATe calipers, Jim Adney can rebuild them. Much better than what you can get out there, especially non ATe.

Thu Apr 23, 2009 8:30 am

i found ate calipers NOS in a local store that are early type 4. I keep hearing 50/50 on they will work. Sending them for a rebuild is not really an option this is my daily.

Thu Apr 23, 2009 9:59 am

They will function, but I believe on hard cornering, when the disc can be deflected on the spindle (not sure just what is bending, though), the piston is pushed further into the caliper housing, so when you hit the brakes again, you have a lower pedal and less braking power. Elfrink covers this difference in his T3 book.

I also don't know why the Type 4 does not have this bending problem; must have a stronger spindle?

Thu Apr 23, 2009 12:07 pm

Ok its like this.

Through chassis # 3112268737, the type 3 used all of the same caliper and rotor. I'm pretty sure....maybe wrong...but I'm pretty sure that this was through 1971.

Now....in 1971...the first year of the 411 on this continent...the 411 used a DIFFERENT part # of caliper...but the same part # of rotor as the 71 and down type 3.

With me so far? Those two calipers used from 71 down type 3 and 71 411 are different...but they are interchangeable in thickness and bolt pattern. Externally there was no difference. Internally.....one had a a guide pin and bushing to keep the rotor flexing from cocking the piston in the bore.

I'm not sure if they quit using the one with the pin when they started putting it on the 411 or started using the one with the pin.....but that pin and bushing inside was the difference. The only real difference. One could argue when they started putting two bleeders on both calipers but that is not what stops you from using them.
Both of these calipers will fit both cars....up through 1971.

Now...if you look at the part # books....the 412 and Porsche 914 started using a different caliper and rotor.....in August of 1972 and on. That caliper and rotor will not fit any of the type 3's. It is wider and uses thicker pads and has a different offset.

So...to recap there were three calipers. Ones that were type 3 And fit all type 3 and the first year of American 411 (that I know of)...and ones that were different internally but bolt up ok to 71 and up to august of 72 411 and all type 3. Anything after august of 1972...will not fit type 3.

As far as why the 411 did not have teh problem with rotor flexing on the front end.....it did. Thats why the 412 got the improved rotor that does not flex. It has the raised boss around the center. Also The front beam and suspension assembly of the type 3 is a good deal heavier than the front suspension of the type 4. Ray
Ray

Thu Apr 23, 2009 12:32 pm

Squarback 1972 and 1973 use a 4-piston caliper
on euro verision i don't know if the US one use it to

Thu Apr 23, 2009 12:36 pm

They show 3 different callipers for the disc brakes.
Up to the end of 1971.
From the beginning of 1972 on, But there was an M Code for the one. M 594 is "re-enforced rotor for Sweden"
But they all have a T-3 part number.
Not T-4.

Thu Apr 23, 2009 12:43 pm

Enfrink describes the T3 pin as being part of a mechanism to return the piston closer to the rotor upon brake release after hard cornering (in addition to the rubber ring's deflection). It wasn't just to keep it square in the bore. But in any case, that prevents interchanging T3 and T4 caliper assemblies.

I put a '73 front beam on my '71, and so I use the later, larger, two-bleeder calipers-- but they are still Type 3 unique parts. What might be confusing is that they started with the same casting, so you might find identical casting numbers, and they are dimensinally identical. The pin mechanism, though, is T3 only.

Not to add confusion, but the rotor, if I remember the box correctly, fits the 914. Forget I mentioned it!

Thu Apr 23, 2009 12:45 pm

Stefan T wrote: Squarback 1972 and 1973 use a 4-piston caliper
on euro verision i don't know if the US one use it to

All T3 cars with disc brakes had four pistons (two on each side).

Thu Apr 23, 2009 1:30 pm

Nope....I have owned 1972 and 1973 type 3's at the same type as I have owned 1972 and 1973 type 4's.

The type 3 caliper through EARLY 1972...bolts right up to type 4 (411 only)...and vica-versa.
The change where there is no cross over...comes in August of 1972. Its purely type 4 after that (which includes 914).

Russ, are you saying that for Sweden...there was a re-enforced type 3 only rotor? Cool!
I'm betting it is not the same re-enforced rotor they used on the 412...because the type 3 would require a totally different spindle to use the type 4 rotor.....if that reenforced rotor is the same as the one on 412.

KTphil...yes...technically by the use of the pin on the inside...they are unique type 3 parts....that however does not stop them for a second from bolting right up to a 411 and functioning perfectly. Been there.
You cannot tell them apart by any means unless you pull a piston and see if the pin is in there. Same basic casting externally...same piston diameter (1.65") , same bolt spacing....same pad, same hardware pack...same rotor thickness and offset.

Also....there is nothing stopping you from bolting a 1971 411 caliper up to a 1971 or earlier type 3 and having it function perfectly.

Yes.....the rotor from type 3 through 1972...fits early 411 and early 914. The operative date...is August of 1972. After that the 411 became the 412 and the 412 and 914 got totally new rotors, pads, calipers and steering knuckles with new spindles.
The type 4 and 914 front brakes have been identical to each other all along. Ray

Thu Apr 23, 2009 3:49 pm

raygreenwood wrote: KTphil...yes...technically by the use of the pin on the inside...they are unique type 3 parts....that however does not stop them for a second from bolting right up to a 411 and functioning perfectly. Been there.

Yes, but he's trying t do the opposite-- use a non-pin T4 caliper on a T3 that should have the pin type.

Thu Apr 23, 2009 4:42 pm

raygreenwood wrote: Nope....I have owned 1972 and 1973 type 3's at the same type as I have owned 1972 and 1973 type 4's.

The type 3 caliper through EARLY 1972...bolts right up to type 4 (411 only)...and vica-versa.
The change where there is no cross over...comes in August of 1972. Its purely type 4 after that (which includes 914).

Russ, are you saying that for Sweden...there was a re-enforced type 3 only rotor? Cool!
I'm betting it is not the same re-enforced rotor they used on the 412...because the type 3 would require a totally different spindle to use the type 4 rotor.....if that reenforced rotor is the same as the one on 412.

KTphil...yes...technically by the use of the pin on the inside...they are unique type 3 parts....that however does not stop them for a second from bolting right up to a 411 and functioning perfectly. Been there.
You cannot tell them apart by any means unless you pull a piston and see if the pin is in there. Same basic casting externally...same piston diameter (1.65") , same bolt spacing....same pad, same hardware pack...same rotor thickness and offset.

Also....there is nothing stopping you from bolting a 1971 411 caliper up to a 1971 or earlier type 3 and having it function perfectly.

Yes.....the rotor from type 3 through 1972...fits early 411 and early 914. The operative date...is August of 1972. After that the 411 became the 412 and the 412 and 914 got totally new rotors, pads, calipers and steering knuckles with new spindles.
The type 4 and 914 front brakes have been identical to each other all along. Ray

so what is interchangeable with a 1973 model?

Fri Apr 24, 2009 12:06 am

KTPhil wrote: raygreenwood wrote: KTphil...yes...technically by the use of the pin on the inside...they are unique type 3 parts....that however does not stop them for a second from bolting right up to a 411 and functioning perfectly. Been there.

Yes, but he's trying t do the opposite-- use a non-pin T4 caliper on a T3 that should have the pin type.
Yes, and what he's trying to do will work.

Using teh non-pin caliper isn't *ideal*, but 99.9% of the time it won't make much difference in braking .. if it makes any difference at all in that 99.9% of the time. And it's certainly closer to ideal than the earlier T3's running around with small-piston Ghia calipers instead of teh proper T3 calipers, or an earlier T3 using those crappy Varga calipers coming out of Brazil...

Fri Apr 24, 2009 4:39 am

What will help to get rid of some confusion....is to quit calling it a type 4 or type 3 caliper.
Its a 411 caliper of a 412 caliper. Both are type 4....but the difference is caliper is night and day.

I agree though...putting a non-pin type caliper that originally came on a 411..... onto a type 3....would be a slight step backward in technology. The flexing issue as noted...is only during hard cornering, but it is an issue.
You would be better off to look for a set of calipers with the pins.
And of course...if you have a 411, either bolt up a set of type 3 pin type calipers.....or better yet.....go to the junkyard and find a 412 and take the spindles and steering knuckles and the backing plates. Then you can bolt up 412 calipers and rotors that are even better than the pin type, type 3 calipers.Ray

Mon Mar 15, 2010 1:14 pm

Quote: All T3 cars with disc brakes had four pistons (two on each side).

Incorrect
all 3 of my type 3s hade Single
(1 on each half of the caliper 67, 70, 71)

each caliper has 2 pistons

Tue Mar 16, 2010 5:06 pm

sharkskinman wrote: Quote: All T3 cars with disc brakes had four pistons (two on each side).

Incorrect
all 3 of my type 3s hade Single
(1 on each half of the caliper 67, 70, 71)

each caliper has 2 pistons

My 68 is the same, disc brakes, single piston calipers.

I have been told the calipers from the late T3 were simply bigger cylinders?