rear "V-caliper" vs. "M" caliper, please jump in Eric Shea |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
rear "V-caliper" vs. "M" caliper, please jump in Eric Shea |
Wes V |
Aug 12 2008, 10:28 AM
Post
#1
|
Member Group: Members Posts: 482 Joined: 11-October 07 From: Los angeles Member No.: 8,211 |
In the process of converting to 5 lug and also rear vented rotors, there appears to be two ways to go about it. Both have been explored and written about by Eric Shea over the years. (Ya, I've done a lot of searching and reading)
One is the usage of a late model 914 rear caliper with spacers placed in the body, to get the needed clearance for the vented rotor. (as I read it; a late model ATE caliper is used and not a rare 914/6 caliper) A spacer is required between the brake rotor and hub (moving the rotor and wheel outward). The rotor (911SC) has to have it's diameter shaved down 4mm) The parking brake cable just hooks up as stock. The other option is to use the "M" caliper from a 911 and also the parking brake assembly. Mounting the parking brake assembly requires grinding and welding on the housing. Hooking up the parking brake cable requires fabrication, but is possible (and can be found by searching this site). Now I can think of plus and minus points for both, but I'd like to hear from others. Wes Vann |
Eric_Shea |
Aug 19 2008, 11:13 AM
Post
#2
|
PMB Performance Group: Admin Posts: 19,278 Joined: 3-September 03 From: Salt Lake City, UT Member No.: 1,110 Region Association: Rocky Mountains |
QUOTE Are there any tricks to ID'ing 76-83 rear M calipers? (I know that the 3" bolt spacing is a given) That's assuming I can't take them apart to verify the shape of the piston. Maybe Jon Von Bovey can weigh in with a picture of his. I saw them in a thread here recently somewhere?? You don't have to take them apart to verify the shape of the piston, you can see it by simply looking at the piston. It is cupped or dished out in the center. One other thing you'll notice about the later calipers is the 10mm cast spacer has sharp corners that better follow the profile of the caliper. Early models were machined and rounded on the corners (see the #11 restoration thread in the Classics forum) (found the picture) (IMG:http://www.914world.com/bbs2/uploads/post-6884-1218677312.jpg) QUOTE If somebody has an "M" caliper, is the thickness of the spacer between the two halves a quick give-away as to if it was a front or rear caliper. (rear having a 10mm spacer, front having a 7mm spacer, per earlier quote) Yes however; why they are both called M-Calipers is beside me. They are two different animals. Fronts have 48mm pistons. Rears have 38mm pistons. Fronts have 7mm spacers. Rears have 10mm spacers. Fronts have M8 fasteners with 13mm nuts and R8 Ribe heads. Rears have M7 fasteners with R6 heads and 11mm nuts. Fronts have a side fluid inlet. Rears have an end fluid inlet. The casting molds and the overall shape and size are totally different. The rear M-Caliper is almost identical to the early 914 front caliper. Same "basic" casting mold with a different fluid inlet and a smaller bore for the pistons. QUOTE Is there any advantage (or is it even possible) to use a front M caliper on the rear, after swapping spacers. Well...48mm pistons in the rear? Huge bias issue. The front M-Caliper nose would have to be shaved as well. The hat of the rear rotor gets in the way and rubs on the caliper. Can it be done? Yes. I know of a -6 that has them on there now but... wow, what a bad match of calipers. |
Lo-Fi Version | Time is now: 8th June 2024 - 07:13 AM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |