 Brake Pad Dragging on Front Rotor, Speader Spring Installed Wrong? |
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| VWTortuga336 |
 Sep 13 2015, 08:24 PM
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#1
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Member  Group: Members Posts: 285 Joined: 5-October 14 From: Kansas City, Missouri Member No.: 17,979 Region Association: None  |
Just installed freshly rebuilt calipers with new pads and hardware on my '74. Now the pad closest to the inside of the car seems to be rubbing on the rotor. I was thinking maybe I had the spreader spring installed incorrectly, but I can't even push the pad back any further by hand either.
Any thoughts on what would cause this?  |
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| stugray |
Sep 14 2015, 09:05 AM
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#2
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Advanced Member Group: Members Posts: 3,825 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
I don't believe the "spreaders" actually do anything to help the pistons push out.
The knockback is achieved by the natural runout in the rotor as it flexes. |
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| mgp4591 |
Sep 14 2015, 09:17 AM
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#3
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914 Guru Group: Members Posts: 5,519 Joined: 1-August 12 From: Salt Lake City Ut Member No.: 14,748 Region Association: Intermountain Region 
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QUOTE(stugray @ Sep 14 2015, 09:05 AM)  I don't believe the "spreaders" actually do anything to help the pistons push out. The knockback is achieved by the natural runout in the rotor as it flexes. That and the square cut seal between the caliper body and the piston. The seal holds back the fluid but it can't overcome the fluid pressure when the pedal is depressed- it only flexes slightly when the brakes are actuated then after the pressure is release, the seal pulls back on the piston until it the flat part is on the piston surface. Gives it a couple of thousandths for the pad to move away from the rotor surface. If the pad isn't dragging on the rotor face, drive it a few miles (20 or so), then check the clearance again. You'll know if the piston is hanging up or not. Good luck! |
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Posts in this topic
VWTortuga336 Brake Pad Dragging on Front Rotor Sep 13 2015, 08:24 PM
Cupomeat I doubt it is the spreader spring.
Remove the spri... Sep 13 2015, 09:12 PM bandjoey Isn't there a metal plate that sits on the pis... Sep 13 2015, 10:29 PM bandjoey Picture from PMB. Thank you. Your 914 brake expert... Sep 13 2015, 10:35 PM stugray Push the piston all the way in using a C-Clamp (ma... Sep 14 2015, 07:11 AM Dave_Darling Are those the right spreaders? They don't loo... Sep 14 2015, 08:59 AM VWTortuga336 I tried pushing the piston back into the caliper. ... Sep 14 2015, 01:27 PM r_towle Bleed the brakes again, if the piston won't st... Sep 14 2015, 01:36 PM
VWTortuga336
Bleed the brakes again, if the piston won't s... Sep 14 2015, 02:17 PM stugray
[quote name='r_towle' post='2237287' date='Sep 14... Sep 14 2015, 02:32 PM VWTortuga336 I removed the bleed nipples, no change. Pistons ar... Sep 14 2015, 03:57 PM porschetub
Just installed freshly rebuilt calipers with new ... Sep 14 2015, 04:49 PM r_towle Finish the job, then troubleshoot it.
With no flu... Sep 14 2015, 06:28 PM |
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