914-6 Brake up grade

[Turboman]

I plan to up grade the original brakes of my 914-6, using 911 aluminum front calipers with the ventilated standard rotors/discs. At the rear the situation is a bit different due to the fact that I want to keep the hand brake. I need to fit an spacer on the rear calipers in order to use ventilated rotors/disks. Anyone know where I can buy the spacers???
Thanks
Francisco

[Cairo94507]

Call Eric Shea at PMB Performance in Sandy, Utah. He is the brake expert when it comes to Porsche. I have that exact set-up for my car and Eric has it on his 914 too. He can address all of your braking concerns.

[Jared at Pelican Parts]

You can use washers. That's what I did.

[Dave at Pelican Parts]

I would not like to use washers in between the two halves of the caliper. I think a machined spacer is far better for that application.

Washers for mounting the caliper to the trailing arm would be fine, assuming you only need 1 or maybe 2 washer's worth of space.

--DD

[Jared at Pelican Parts]

I beleive there is a factory spacer that goes in between the caliper halves. If you are just trying to run 914-6 rear rotors, you need to offset the calipers where it bolts to the trailing arm. That can indeed be done with just washers.

Sorry if i wasnt clear enough.

[Jim Dorociak]

You need to get a 911 rear caliper and take it apart to get the spacer to widen the 914/6 rear caliper. You need to go find the aritcle about this as it has been a very long time since I did mine. There is a spacer you put behind the vented rotor that I had made out of the old 911 rear rotor 3/16" or something like that. There are little rubber O rings you get from Porsche when you install the 911 caliper spacers and bolt everything back up. Jim

[larrym]

the factory spacer is a 911E part - maybe still available - and you can then use 911 vented rotors

- 911 rotor bolts right on with no mods required

my GT has that setup from Germany - (the TUV would never have allowed a car to be registerd without the e-brake)

S-alum calipers are 'flex-y' - but if you get the correct thicker brake pads they'll work OK - i had 'em from Germany, but they are long gone

- i switched to A calipers when i started racing the car in the early '90's - cuz you have lots more choices for performance brake pads available if you use them

.

[Jim Dorociak]

I remeber a little more about the conversion to a vented rear rotor. It is a SC rear rotor, you have to turn down the overall size of the rotor slightly to match the size of the 914/6 rotor. Because you are splitting the 914/6 rear caliper and inserting the spacer block from a 911 rear caliper you do not loose the emergency brake functionality. Jim

[Scrappy]

Have Eric @ PMB restore a set of Ferrari 308 rear calipers for you. They have the spacer and the only difference between them and the 914/6 rear (other than the spacer) is the location of the bleeder. A second bleeder will be added in the restoration. Wella ... 914/6 GT rear calipers.

[Dave at Pelican Parts]

I believe the pistons in the 308 caliper are also larger than the ones in the 914-6 caliper, which in turn are larger than the ones in the 914-4 caliper. Your brake balance will be changed, which may be a good thing or may not.

I also believe that the 308 guys were using the hard-to-find 914-6 calipers as cheap replacements for the really-hard-to-find 308 caliper...

--DD

[mepstein]

Originally Posted by Dave at Pelican Parts

I believe the pistons in the 308 caliper are also larger than the ones in the 914-6 caliper, which in turn are larger than the ones in the 914-4 caliper. Your brake balance will be changed, which may be a good thing or may not.

I also believe that the 308 guys were using the hard-to-find 914-6 calipers as cheap replacements for the really-hard-to-find 308 caliper...

--DD

308 calipers are the same ATE casting and piston as 914-6 calipers. The bleeders are reversed on the 308's and they have a spacer for vented rotors. I obtained a core set of 308 calipers and Eric at pmb restored them and machined the bleeder in the correct location, duplicating the 914-6 GT caliper. They are hard to find but Eric just had a pair for sale. Sold in about a day. Both 308 & 914-6 calipers are out there but you have to ask around and be prepared to pay $.

[Turboman]

Thanks to all for the comments and recommendations.
-For me, the aluminum calipers are OK, I do not plan to use my 914-6 on the track.
-Does anyone have the part number of the spacer I need for the rear calipers?
-I do not feel going the way of the Ferrari calipers will do any good to my savings.
-How about to start with 914-4 rear calipers and re-bore them to use 914-6 pistons?
Some times for Porsche fans living away from USA, like me in Costa Rica, we need to do all, there is not a local expertise to help.There is not local shops to send the parts. Forums like this one, or help from other Porsche experts like Bruce Anderson or our missed friend Jim Pasha is the only source.
Thanks again
Francisco

[Jared at Pelican Parts]

Originally Posted by Turboman

Thanks to all for the comments and recommendations.
Francisco

If you arent taking the car to the track, I see no reason to upgrade the rear brakes at all. You should be just fine upgrading the front ones and leaving it at that.

[Eric_Shea]

If you are just trying to run 914-6 rear rotors, you need to offset the calipers where it bolts to the trailing arm. That can indeed be done with just washers.

If you're running 914-6 calipers and 914-6 rotors, there's no need for spacers under the mounting ears. They simply bolt right up. Same goes for -4 caliper and -6 rotors (the -6 rotor should be shaved though).

That said, we have the spacer kits (for both 914-6 calipers and 914-4 calipers) and, if you want to space them out, and use vented 911 rotors, you'll need about 4.5mm of washers under the ears and, it's best to get longer mounting bolts at that time as well. It's not a 911E part... all 911's have them from 1970 through 1983. It's a rear M-Caliper spacer and fasteners. For the -4 calipers, it's a kit we developed for those specifically as they have a totally different profile and different (M7) fasteners. Also, a 911 rotor does not bolt right up (spacers needed as described) nor would it need to be shaved with a real 914-6 caliper. With a spaced 914-4 caliper you need to bring the diameter down to 281mm. Both calipers would need the 4.5mm worth of spacers under the ears to get them to align with the 911 rotors offset. Also, most trailing arms don't allow a 4-5mm backspacing of the caliper without modifying the inner venting clearance adjustment tube.

You can't bore out a 914-4 caliper without losing the dust boot. Then you'll be left with the same smaller 914-4 pad. So absolutely not worth the time, money or effort. THIS IS WHAT IS UNCLEAR: You mention upgrading the calipers for your 914-6. If you have a real 914-6, you have the best rear calipers available for upgrading. Again, we can add or sell you the spacer kits for those if you need them.

For fronts you can go with your stock 914-6 struts (assuming this is a real 914-6 and not a converted -4) and add what Mark is showing. Those Brembos bolt to the standard 914-6 (911T) strut and have roughly the same pad size as the S-Caliper (only a few mm shorter). This would save you from having to purchase the 3.5" Koni or Bilstein struts.

Ferrari calipers and real 914-6 calipers are basically NLA even in used circles. As mentioned herein, we sold our last set in a matter of minutes for around $1,600.00

Also as mentioned herein, spot on... if this is a street 914-6 adding vented rotors to the rear will net you nothing but less money in your wallet. If the car is a real -6 (seeing as how you're looking to upgrade to vented rotors up front, I'd say it probably isn't) and it's still a narrow body car, the best upgrade you can get is a set of Porterfield R4-S pads, bed them properly and enjoy the ride.

[914-six]

Just want to set the records straight. I currently have a couple of 73' Dino 246 GTS in the shop. One for a suspension and brake rebuild and I just finished rebuilding several sets of 914-6 GT front (908) and rear "GT" calipers about a year ago. The 246 GTS and the 914-6 rear calipers are 100% identical, same piston Dia. 38mm, same rebuild kit, same brake pads, Ect. The only difference is the location of the bleeder vale as mentioned earlier and the brake pad pin holes are the same size upper and lower on the Dino. I have seen a few sets of these with two bleeder valves on the caliper, they were on Dino's. I guess we know where our calipers are going...