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I am re assembling my rear calipers after rebuild and I and I am trying to figure out the 20 degree position for the piston ... I made a 20 degree guage, but I am not sure about the orientation . I found these two pictures online but they are completley opposite of each other .( I think the silver caliper is Dwayne's).. Can anyone tell me which is correct ?
Thanks for any help.
I am re assembling my rear calipers after rebuild and I and I am trying to figure out the 20 degree position for the piston ... I made a 20 degree guage, but I am not sure about the orientation . I found these two pictures online but they are completley opposite of each other .( I think the silver caliper is Dwayne's).. Can anyone tell me which is correct ?
Thanks for any help.
They are both correct. You are confused because the two pictures are taken from opposite sides of the calipers.
This can be confusing.
This is how I do it:
Remember that the rotor, when turning in the forward direction, would hit the tip of the 90 degree angle of your triangle first. You can hold the caliper in the position where it goes on the car and envision this.
Thanks Greg ..... That helps explain it, and I will position the caliper on the rotor and visualize how the 90 degree hit the rotor.....But after staring at the 2 pictures again, I still think they are in different positions. If you turn the silver caliper picture clockwise a quarter turn then both pictures are in the same position (yes??).... yet the piston cutouts are on opposite sides in both pictures.
I will stop trying to overthink it and have a beer (it may come clear after that) ...haha
Again... thanks for your help!!
Thanks Greg ..... That helps explain it, and I will position the caliper on the rotor and visualize how the 90 degree hit the rotor.....But after staring at the 2 pictures again, I still think they are in different positions. If you turn the silver caliper picture clockwise a quarter turn then both pictures are in the same position (yes??).... yet the piston cutouts are on opposite sides in both pictures.
I will stop trying to overthink it and have a beer (it may come clear after that) ...haha
Again... thanks for your help!!
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I can't see the bleeder on the red caliper....so they could be wrong.
I do exactly as I described, which i think I poorly descibed....but still can't do any better, now.
Just remember that the rotor, I when turning in the direction of forward travel, must hit the "cutout" area first, when the caliper is in the correct position. The smallest angle on your triangle points towards the wheel.
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
Just remember that the rotor, I when turning in the direction of forward travel, must hit the "cutout" area first, when the caliper is in the correct position. The smallest angle on your triangle points towards the wheel.
Thanks again Greg..... The more you explain it , the more I understand it !! I'm going to initially set it up to match the silver caliper and then mount it on the rotor to see how it lines up per your description. Then dial it in with my home made handy dandy gauge.
Maybe one is front and one is rear - this reads from the service manual:
........
4. Check 20” piston position and if necessary adjust
with piston turning pliers.
Hold piston gauge at bottom guide surface on
front brake caliper.
Hold piston gauge at top guide surface on rear
brake caliper.
09-26-2015, 08:48 PM
Rear brake caliper piston position (20 degree)
