|
|
|
|
| Author |
|
|
UFLYICU
|
Can someone tell me why these look broke?
In the image, the yellow finger is pointing to the edge of the piston, which appears to have a section missing. Is this normal? The ones on my car have the same thing, and I thought I needed to get new pistons.
__________________
_______________________ Racer Rix Spec911 #5 prc-racing.com |
||
01-30-2005, 08:35 PM
|
|
|
Registered
Join Date: Feb 2001
Location: Viera FL
Posts: 5,642
|
Normal. They are supposed to be that way. If you remove the pistons, make sure they go in the same way they came out.
AFJuvat
__________________
Es geht nicht darum wie schnell man faehrt, sondern wie gut man schnell fahren kann. Ihr Brunnen der nutzlosen Porsche Information |
||
|
01-30-2005, 08:52 PM
|
|
|
UFLYICU
|
Wow, thanks. You learn something new every day.
__________________
_______________________ Racer Rix Spec911 #5 prc-racing.com |
||
|
01-30-2005, 08:54 PM
|
|
|
Registered
Join Date: Nov 2001
Location: Bethesda, MD
Posts: 1,625
|
this is actually a very big deal, and not something I would eyeball.
There is a special tool to make sure that the piston is oriented correctly, if you plan on rebuilding a few calipers it's a worthwhile investment. it makes sure that "broken section" as you put it is angled correctly relative to the rotor approaching it and will affect braking performance/feel especially if they differ from side to side.
__________________
-Andy '67 912, '92 C2, and '93 RSA - all gone 
|
||
|
01-30-2005, 10:24 PM
|
|
|
Registered
Join Date: Nov 2001
Location: Bethesda, MD
Posts: 1,625
|
this is actually a very big deal, and not something I would eyeball.
There is a special tool to make sure that the piston is oriented correctly, if you plan on rebuilding a few calipers it's a worthwhile investment. it makes sure that "broken section" as you put it is angled correctly relative to the rotor approaching it and will affect braking performance/feel especially if they differ from side to side.
__________________
-Andy '67 912, '92 C2, and '93 RSA - all gone
|
||
|
01-30-2005, 10:24 PM
|
|
|
Registered
Join Date: Jan 2002
Location: Long Beach CA, the sewer by the sea.
Posts: 37,710
|
You can do it with a protractor. 20* from a radial line drawn thru the center of the rotor. Turn them out towards the edge of the rotor at the 20*. You won't get squealing.
|
||
|
01-30-2005, 10:44 PM
|
|
|
Registered
Join Date: Aug 2002
Location: Galivants Ferry, SC
Posts: 10,550
|
The "tool" for the proper 20 degree rotational angle ( which the "broken" piece provides !) ...can be had at any Mercedes dealer for $10......
The 20 degree rotation allows the piston to "more evenly" put pressure on the backside of the pad...otherwise the leading(?) edge wears out faster than the trailing (?) edge of the pad.....the "break" is therefore put there on purpose...clever Germans ! Wil
__________________
Wil Ferch 85 Carrera ( gone, but not forgotten ) |
||
|
01-31-2005, 04:48 AM
|
|
|
undervalued member
|
a speed square (see carpenter) to get your 20* and a chuck of cardboard work well.
__________________
78SC PRC Spec911 (sold 12/15) https://www.youtube.com/watch?v=f7I6HCCKrVQ Now gone: 03 996TT/75 slicklid 3.oL carb'd hotrod 15 Rubicon JK/07.5 LMM Duramax 4x/86 Ski Nautique Correct Craft |
||
|
01-31-2005, 06:39 AM
|
|
|
Schleprock
Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 16,639
|
Quote:
__________________
Kevin L '86 Carrera "Larry" |
||
|
01-31-2005, 06:47 AM
|
|
|
UFLYICU
|
Dang, the learning never ends!
They weren't actually removed, so the orientation is correct. I had my rotors turned, and I'm putting in new pads, and it just looked odd. Thanks again.
__________________
_______________________ Racer Rix Spec911 #5 prc-racing.com |
||
|
01-31-2005, 08:34 AM
|
|
Track Whore
New Daily Driver
Former Daily Driver
the 23 car
domino
