914 Brake Caliper info, Whats the internal pin for? They stick |
|
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. |
|
914 Brake Caliper info, Whats the internal pin for? They stick |
Thorshammer |
Mar 12 2006, 10:21 PM
Post
#1
|
Senior Member Group: Members Posts: 749 Joined: 11-November 03 Member No.: 1,335 |
Okay,
So I am rebuilding a set of calipers of a customers 914 FP racecar. One front is a standard "M" caliper with 3 inch spacing and a center pin internal of the piston. This pin sticks out from the center of the caliper piston bore and the piston center has a rubber seal and the pin sticks into the piston. Anyone know what this pin is for???? I also have another front caliper which has no center pin and the caliper piston is not cupped on the fluid side, so the second caliper has less fluid in it. I found a caliper in the customers spares kit which had a 411 XXX XXX part number on it. From my VW days I deduced this is probably a 411 VW caliper. Same piston diameter and 3.0 inch bolt spacing. The rears are standard early front calipers from a 914-4. Here are the questions: What calipers will bolt onto a 3.0 inch bolt spacing that are two piston calipers??? for the front. What calipers are the same bolt spacing as 914 front calipers, and are the same piston size? Observations: When rebuilding the standard 914 calipers (with the center pin) the caliper pistons move really hard, even with use, or new with Brembo caliper grease. The "411" caliper pistons move very easily, and I mean this is a big difference. They also retract better, when on the car, you can actually turn the wheel much better than the other calipers. I am at a loss for whether a piston design that has a cup on the fluid side (more fluid volume) will be better for heat dissapation, or if a piston design that has an almost flat back side (fluid side) will (less fluid) work better. Does anyone make a ceramic insert so the pads will not transfer heat to the pistons to the fluid as easily. Obviously I am looking for a performance improvement, In two ways: One piston retracts much better than the other, so less rolling resistance One piston design that will keep the brakes cooler This is my dilema. Erik Madsen |
Thorshammer |
Mar 15 2006, 06:38 PM
Post
#2
|
Senior Member Group: Members Posts: 749 Joined: 11-November 03 Member No.: 1,335 |
Thanks for everyones input. Here is what I am trying to do: Choose the best piston design for heat dissapation Get the pads to not cause drag on the rotors. This is friction, and I don't need it. I have 7/10 front tilton Master cylinders and 5/8 rear cylinders. This gives me good fluid volume so pedal travel is not an issue. With the 23mm cylinder I doubt this is an issue either. As for the struts I am using on this customers car, they are 911 struts with a 3.0 inch bolt spacing. I have noticed the VW 411 caliper has the same bolt pattern, but without the center pin, and the caliper piston is shaped differently. Thanks to all that responded. Erik PS: Brent I wish I could use Brembos or Wilwoods. Would that be nice. |
Lo-Fi Version | Time is now: 28th June 2024 - 01:59 PM |
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 ... |