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-   -   Solution for pressuring piston from caliper (http://forums.pelicanparts.com/porsche-911-technical-forum/1090375-solution-pressuring-piston-caliper.html)

autobonrun 04-06-2021 04:17 PM

Solution for pressuring piston from caliper
 
When pistons are tight and partially frozen in calipers, it’s always been an issue for me to supply enough pressure to move them. Hose connections always leaked too much. I finally found a fitting that screws directly into the caliper’s brake line inlet. The good news is the pressure side has the same connection as a tire stem so it’s easy and leak free to apply pressure. I’ve posted a photo wi manufacturer’s information.


http://forums.pelicanparts.com/uploa...1617754572.jpg


http://forums.pelicanparts.com/uploa...1617754607.jpg

djpateman 04-06-2021 04:24 PM

UMM, if you are trying to use a 1/8" NPT thread in place of the correct 10mm 1.0 pitch, then you are asking for problems. For thirty years of rebuilding calipers I have used a pedal cluster with master cylinder and brake lines to pop the pistons hydraulically. So you don't really need to remove from the car.

$yncro 04-06-2021 05:01 PM

I need a solution on my frozen cylinders too.. I like the pedal approach but I'm rebuilding
All my brake system. How about adapter to the 1/8 npt like this one.
https://www.speedwaymotors.com/Earls-02112ERL-Hardline-Adapter-1-8-Inch-NPT-10mm-x-1-0-Concave,390758.html

Oops.. I guess that's backwards..
I'm sure there's a 10 mm male to 1/8 female somewhere.

Joe Bob 04-06-2021 05:12 PM

Zirc fitting and a grease gun.

autobonrun 04-06-2021 05:22 PM

Quote:

Originally Posted by djpateman (Post 11287417)
UMM, if you are trying to use a 1/8" NPT thread in place of the correct 10mm 1.0 pitch, then you are asking for problems. For thirty years of rebuilding calipers I have used a pedal cluster with master cylinder and brake lines to pop the pistons hydraulically. So you don't really need to remove from the car.

I don’t think I’m a good enough mechanic to replace those o-rings in the calipers with the calipers still on the car. Doing it on the bench was challenge enough. Like you I was also concerned about the thread pitch difference, so I only threaded in until I met resistance. That was enough to be air tight without causing any damage to the thread. I like the idea of a grease gun. A non compressible liquid is always the preferred method to move a piston.

autobonrun 04-06-2021 05:26 PM

Quote:

Originally Posted by Joe Bob (Post 11287485)
Zirc fitting and a grease gun.

I’ll look into this setup. I know a tool store that probably has it. I’m not familiar with a Zirc fitting. I’ll need to research it. Do you just use regular brake fluid in the grease gun? I assume you don’t want to get grease in the caliper.

john walker's workshop 04-06-2021 05:27 PM

Easy to fab up something like this.
http://forums.pelicanparts.com/uploa...1617758528.JPG
http://forums.pelicanparts.com/uploa...1617758528.JPG

autobonrun 04-06-2021 05:28 PM

Quote:

Originally Posted by john walker's workshop (Post 11287501)

Wow. That’s a nice setup.

Joe Bob 04-06-2021 05:32 PM

A zirc fitting is a grease fitting, use a grease gun with grease in it.

Old Indian trick as my Dadz would say.

autobonrun 04-06-2021 05:37 PM

Quote:

Originally Posted by Joe Bob (Post 11287511)
A zirc fitting is a grease fitting, use a grease gun with grease in it.

Old Indian trick as my Dadz would say.

Thanks.

Joe Bob 04-06-2021 05:40 PM

Put a block of wood between the pistons and pump SLOWLY.....sometimes it can be quite explosive and you don't want them whacking themselves together.

LakeCleElum 04-06-2021 05:46 PM

Quote:

Originally Posted by Joe Bob (Post 11287511)
A zirc fitting is a grease fitting, use a grease gun with grease in it.

Old Indian trick as my Dadz would say.

Joe Bob is Correct. Just used it last week on 3 motorcycle calipers that had been sitting since 1992. Slick trick.

$yncro 04-06-2021 06:17 PM

Quote:

Originally Posted by john walker's workshop (Post 11287501)

Excellent!! I might copy this one.
Thanks!

Joe Bob 04-06-2021 06:20 PM

John Walker/Rube Goldberg:D

Carl S. 04-06-2021 06:39 PM

I used a diesel injector pump from Ebay adapted to the brake lines. Mine were frozen Solid!!! pumped them full of water to free them up. I used a rubber stopper to plug up the loose one and freed the other.

Slick!!!!!
Platted and rebuilt them myself and turned out Sweet.

autobonrun 04-06-2021 07:10 PM

Quote:

Originally Posted by Carl S. (Post 11287567)
I used a diesel injector pump from Ebay adapted to the brake lines. Mine were frozen Solid!!! pumped them full of water to free them up. I used a rubber stopper to plug up the loose one and freed the other.

Slick!!!!!
Platted and rebuilt them myself and turned out Sweet.

I used the piston that popped out as my stopper by pressing it in slightly then held it in that position using a c-clamp while I applied pressure to the caliper. Both my rear calipers had a frozen piston. The fronts came out easily.

I can’t imagine trying to rebuild a four or six piston caliper. Holding one in place made my day.

Arlo911 04-06-2021 11:33 PM

Use the grease gun. It's messy but a whole lot safer than using compressed air. I just removed some pistons from aluminium S calipers this way, works very well

cmcfaul 04-07-2021 10:20 AM

just use the car. Pull the caliper off the disk and step on the break. One side will pop out. Gently use the the piston to clog the hole and step on the break again and the other piston will com out. no need to overcomplicate

autobonrun 04-07-2021 12:31 PM

Quote:

Originally Posted by cmcfaul (Post 11288198)
just use the car. Pull the caliper off the disk and step on the break. One side will pop out. Gently use the the piston to clog the hole and step on the break again and the other piston will com out. no need to overcomplicate

You can’t pull the caliper off the disk with the close coupled hard metal brake line still attached. It’s an exact fit and there is zero give in the line. Otherwise good solution.

cmcfaul 04-07-2021 02:15 PM

Did it a week ago. No issue at all.

Chris


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