o-ring piston question

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Mar 6, 2011 | 10:37 PM

biscuitville

Thread Starter

Instructor

Joined: Jan 2011

Posts: 146

Likes: 2

From: Hillsborough NC

o-ring piston question

I have read in several threads that when using o-ring style brake caliper pistons/seals, the springs should be left out. Why leave them out?

Mar 7, 2011 | 05:44 AM

HamadUP

Melting Slicks

Joined: Jan 2003

Posts: 2,877

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From: Doha

St. Jude Donor '08

when I opened a new o-ring caliper I found that they used a spring in there, been on the car for few years now with no problems at all, so I guess its OK to use the spring.

Mar 7, 2011 | 07:11 AM

Brooklinite

Burning Brakes

Joined: Jan 2006

Posts: 1,152

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From: Kawartha Lakes and PEC, Ontario

The fit is much tighter with the o-rings. You could use the spring but likely wouldn't provide enough pressure to move the piston anyway.

Mar 7, 2011 | 06:02 PM

Scott Marzahl

Le Mans Master

Joined: Apr 2005

Posts: 6,339

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From: Seattle Area WA

The piston will not move with the force provided by the wimpy spring with O rings like it will with standard lip seals. I left the springs out when I rebuilt mine.

Mar 7, 2011 | 07:16 PM

wcsinx

Team Owner

Joined: Mar 2002

Posts: 24,160

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Quote:

Originally Posted by Brooklinite

The fit is much tighter with the o-rings. You could use the spring but likely wouldn't provide enough pressure to move the piston anyway.

Exactly

I think they just include them in the o-ring kits because it's cheaper than answering the phone calls from ppl wondering where their springs are. See for yourself. Install them with and without while the caliper is off. They don't generate near enough pressure to move a o-ringed piston.