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macBdog

Slightly OT because we are talking about '73 911 brakes here.

The pistons are stuck fast in the caliper bores and I'd like to hear some suggestions for getting them out. Methods I have tried already:

* Compressed air into the caliper... up to 80psi (dangerous) and still no movement
* Vice grips and pulling
* Welded a bolt onto the piston and pulled hard
* Penetrating spray (INOX) into the caliper.

Running out of ideas here!
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1979 931 with a 350 chev
1973 911E with EFI

Lizard · Posted: Thu Dec 28, 2006 10:55 am Post subject:

put a block of wood so that the piston cannot come out of the bore, then fill the chamber with coke, let it sit overnight, put compressed air into it, upto 150PSI.
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3 928s,

Rooy · Joined: 16 Jul 2005 Posts: 41 Location: Neenah, WI

I agree with Lizard, use a block of wood and use more pressure. I've had to use 100+ psi in many cases. Could also try filling the caliper with a penetrating oil and letting it sit. But if the piston is that stuck it sounds like there's some nasty corrosion going on which probably means the bore or piston is junk anyways.
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Andrew
Neenah, WI
'78 924 with dual Dellortos

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Grease gun is much safer than air.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

StienbargerR · Joined: 28 Oct 2005 Posts: 1362 Location: Richmond, IN

Hey, nice choice in the Model year! I really love all the pre-73 911's. Very cool cars. If you ever get sick of it, just send it my way!

Ryan
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1978 924 NA
-250lb lowering springs, Euro Pistons

Kenodog · Joined: 25 Jun 2003 Posts: 2669 Location: Vancouver,B.C.

DO NOT USE COMPRESSED AIR !!! THIS IS VERY DANGEROUS !!!

The proper method is either a compressed oil gun or grease gun as Rasta said. Oil and grease themselves do not compress so when the piston (or rotten casing) does let go the pressure will just ooze out. Messy but safe. When compressed air finally finds a way out it does so violently. Think missing fingers or take an eye out violent.
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1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140

Lizard · Posted: Thu Dec 28, 2006 4:23 pm Post subject:

funny when I rebuild brake calipers for a company that is how we always disassembled them was with compressed air, sure if you are an idiot then you will loose a finger or 2
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3 928s,

Kenodog · Joined: 25 Jun 2003 Posts: 2669 Location: Vancouver,B.C.

So just because your boss told you to do something makes it the right way to do it ? Fishing with dynamite also works well but that doesn't mean it's the best or safest way to do it.
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1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140

924RACR · Posted: Fri Dec 29, 2006 12:21 am Post subject:

I'd try tapping it in to the bore a bit with a hammer to break it loose first...

FWIW I've always used compressed air to get them out, but haven't ever had one stick that bad, and I always take care.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

macBdog · Posted: Fri Dec 29, 2006 9:24 am Post subject:

My compressor tops out at ~120 psi and that didn't budge them so I have taken them to a brake and clutch place.

One came out at ~70psi and that was pretty scary. It was like a gun going off in the workshop. I don't have a grease gun that will seal onto to the calipers either. Would have liked to try the coca cola trick but my old man was getting impatient.

StienbargerR: thanks but no way buddy!

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1979 931 with a 350 chev
1973 911E with EFI

emoore924 · Joined: 13 Apr 2004 Posts: 2822

Aaaahhhh, you'll put yer eye out!!