annealing copper crush washers fixed my brake leak - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cell · 07-25-2007, 02:30 AM

so I have been doing a complete brake overhaul, which includes replacing my wheel cylinders.

after replacing the wheel cylinder and brake hose on one wheel, I had a small leak right where the brake hose meets the surface of the wheel cylinder.

after taking it all apart again, I noticed that the surface of the wheel cylinder wasn't completely flat. in fact it was easy to tell with the naked eye that it was not flat.

after filing it down to get a nice even, flat mating surface, I reassembled and found I still had the brake leak. it was slightly improved, but it still leaked very slowly when I depressed the brake pedal.

then I started reading about how copper work-hardens -- it gets stiffer and more brittle as you bend it, roll it, etc. I also read about how you can anneal it (rearrange the crystalline structure of the metal to make it more malleable) by heating it until it glows red for a short while and then cooling it.

so I decided to experiment with this. I went to harbor freight and bought their assortment of 100 copper washers for $8.

it occurred to me that copper washers are punched from a sheet by a press, and that sheet was created by rolling a copper ingot. both of those steps should work-harden copper, so I had a hunch that perhaps the copper washers as I bought them were already hardened, and that I might have better luck getting a good seal on my brakes if I annealed the washers before crushing them.

so I took a torch and heated a selection of washers until they glowed red, and held them at that state for about 20 or 30 seconds, then cooled them with water. I then carefully bent the annealed washers using two pair of pliers, paying close attention to how much force it took to bend them. I then bent some of the washers which I hadn't annealed, and my assumption was correct -- they were more difficult to bend, because they were hardened.

after installing my annealed copper crush washer my leak was gone!

YAY SCIENCE!

here are the above pictures in higher resolution:
http://cell.dreamhosters.com/photos/...crush-washers/

cdowns · 07-25-2007, 06:36 AM

a very interesting solution// GOOD THINKING!!!

Sport/Truck · 07-25-2007, 08:15 AM

Good idea & great write up!

s/t

CrashBob · 07-25-2007, 08:26 AM

Quote:

Originally Posted by cell

YAY SCIENCE!

[/url]

Yay Metallurgy! Good thinking and excellent report. We could use a guy like you in our metallurgy lab.

**truckdude239** · 07-25-2007, 08:50 AM

Umm I Think I'd Have Just Take Them Abck And Got New Ones Lol

07-25-2007, 02:30 AM	#1
cell Active Member Join Date: Nov 2005 Location: Austin Posts: 217	annealing copper crush washers fixed my brake leak so I have been doing a complete brake overhaul, which includes replacing my wheel cylinders. after replacing the wheel cylinder and brake hose on one wheel, I had a small leak right where the brake hose meets the surface of the wheel cylinder. after taking it all apart again, I noticed that the surface of the wheel cylinder wasn't completely flat. in fact it was easy to tell with the naked eye that it was not flat. after filing it down to get a nice even, flat mating surface, I reassembled and found I still had the brake leak. it was slightly improved, but it still leaked very slowly when I depressed the brake pedal. then I started reading about how copper work-hardens -- it gets stiffer and more brittle as you bend it, roll it, etc. I also read about how you can anneal it (rearrange the crystalline structure of the metal to make it more malleable) by heating it until it glows red for a short while and then cooling it. so I decided to experiment with this. I went to harbor freight and bought their assortment of 100 copper washers for $8. it occurred to me that copper washers are punched from a sheet by a press, and that sheet was created by rolling a copper ingot. both of those steps should work-harden copper, so I had a hunch that perhaps the copper washers as I bought them were already hardened, and that I might have better luck getting a good seal on my brakes if I annealed the washers before crushing them. so I took a torch and heated a selection of washers until they glowed red, and held them at that state for about 20 or 30 seconds, then cooled them with water. I then carefully bent the annealed washers using two pair of pliers, paying close attention to how much force it took to bend them. I then bent some of the washers which I hadn't annealed, and my assumption was correct -- they were more difficult to bend, because they were hardened. after installing my annealed copper crush washer my leak was gone! YAY SCIENCE! here are the above pictures in higher resolution: http://cell.dreamhosters.com/photos/...crush-washers/ Last edited by cell; 07-25-2007 at 02:31 AM.

07-25-2007, 06:36 AM	#2
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: annealing copper crush washers fixed my brake leak a very interesting solution// GOOD THINKING!!! __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

07-25-2007, 08:15 AM	#3
Sport/Truck Sierra Grande Club Join Date: Jan 2007 Location: New Mexico USA Posts: 2,433	Re: annealing copper crush washers fixed my brake leak Good idea & great write up! s/t __________________ 1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe.

07-25-2007, 08:50 AM	#5
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,233	Re: annealing copper crush washers fixed my brake leak Umm I Think I'd Have Just Take Them Abck And Got New Ones Lol __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube



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