What is your opinion on soaking old rubber parts(50’s) in brake fluid to make them more pliable.

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outboardnut
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What is your opinion on soaking old rubber parts(50’s) in brake fluid to make them more pliable.

Postby outboardnut » Thu Sep 13, 2018 8:24 am

I am getting conflicting reports on the net. I was wondering what your experience is.
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NJ-boatbuilder57
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Location: New Jersey

Re: What is your opinion on soaking old rubber parts(50’s) in brake fluid to make them more pliable.

Postby NJ-boatbuilder57 » Thu Sep 13, 2018 8:37 am

I have a friend who's a research chemist at Exxon and works in the development of all sorts of rubber & plastics. I asked him this very question about bringing old cowl gasket material back to life. He said that once the plasticizers have dried out & left the material, there's not much you can do to bring them back. Newer polymers have much longer lifespans, but once the old stuff is shot, you can pretty much forget about it.

That's what he told me, anyway....and he's forgotten more than I'll ever know!

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Tubs
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Re: What is your opinion on soaking old rubber parts(50’s) in brake fluid to make them more pliable.

Postby Tubs » Thu Sep 13, 2018 10:36 am

After seeing Mumbles leaking crankshaft seal
video several times I put some oil around the top
seal on this Martin to see what would happen
and I got exactly the same thing. When the
new seals came and I decided to do another
video with my still camera before I changed it.
Its video option is better for close-ups than my
video camera. The leak was now gone.

At the end of the video it shows the bottom seal.
You can see that it is hard and any attempt
to get the rubber to move resulted in
breakage. I soaked it for several weeks but
it never became flexible.

This would seem to indicate to me that there are
conditioner's in the oil to keep the seals flexible
but if a seal gets so dried out its as hard as this
bottom seal it cant be rejuvenated.

I have 1960 Evinrude from the original owner.
I know its history and its been run every year
since new except for one. It still has its original
crank shaft seals. Gear case seals needed
changing in 2010. Discovered the driveshaft
seal (O ring) at the crank shaft had failed decades
before and resulting in a considerable amount
of damage. I now plan to replace that seal every
10 years.

Here is the video.
https://www.youtube.com/watch?v=i75feumBrgU
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Bob D
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Location: Staten Island NY

Re: What is your opinion on soaking old rubber parts(50’s) in brake fluid to make them more pliable.

Postby Bob D » Thu Sep 13, 2018 12:14 pm

Here is what I use for old rubber. I spray it on.
Bob D


https://www.youtube.com/watch?v=-wSVr4I5PLE
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amuller
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Re: What is your opinion on soaking old rubber parts(50’s) in brake fluid to make them more pliable.

Postby amuller » Thu Sep 13, 2018 12:35 pm

Interesting subject. My impression is that the "reseal" products--often sold for use in automatic transmissions--are solvents that are absorbed by rubber and cause swelling. They can cause a beneficial reduction in leakage (not usually permanent) but aren't plasticizers and don't do much to restore flexibility.


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