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2015 Porsche Boxster S
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Discussion Starter · #1 ·
Guys,
What do you use to rejuvenate old rubber oil rings that have gotten hard? I purchased a gasket kit for my S65 Honda and the old oil rings are pretty hard.
 

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I use Bars Leak AutomaticTransmission Repair .
I've used it in hydraulic systems to stop leaking seals and I've used it in a bike transmission for the same reason .
It works . Not immediately , but given a little time the seals are back to doing what they do best . ;)
 

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Discussion Starter · #3 ·
Thanks, I'm looking for something I can soak the o-rings in for a couple days prior to assembling the engine. I want the rings ready before I assemble it.
 

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Thanks, I'm looking for something I can soak the o-rings in for a couple days prior to assembling the engine. I want the rings ready before I assemble it.
So , you're gonna use Bars Leak Automatic Transmission Repair or did you find some Old Hard O-ring Magic Repair that you're not telling us about ?
 

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Discussion Starter · #5 ·
There are many recommendations on the web using a combination of chemicals that I don't have (oil of wintergreen, etc). I once used the wintergreen on my slot cars tires when racing, but it is pricy. Some recommend also placing the rubber parts in water heated to near boiling temperature. I'm just figuring you guys know of something simpler that is a standard method vintage bike guys have used for years.
 

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Ace Tuner
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Is it not possible to match the O-ring with a new one?
Most motorcycle shops keep a supply of aftermarket and factory O-rings in stock.

S F
 

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O-rings are rather inexpensive. Why not just replace them. Is it some odd size no one carries?
 
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Discussion Starter · #8 ·
Good idea. Since I now have the OEM replacements, I can maybe match them with new O-rings from an auto parts place or even Ace Hardware. Still, I would rather soften up the OEM units.
 

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Rubber swells in the presence of gasoline, I know that from just trying to keep rubber o-rings on the fuel fill cap.
There is no such thing as something to make natural rubber new again because it comes from Hevea Brasiliensis aka a rubber tree ;)
 

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Rubber swells in the presence of gasoline, I know that from just trying to keep rubber o-rings on the fuel fill cap.
There is no such thing as something to make natural rubber new again because it comes from Hevea Brasiliensis aka a rubber tree ;)
True that^ .
But , there is 'stuff' that helps bring it back from certain death . ;)
I know that from using the aforementioned Bars Leak for many years with excellent results .
 

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Found it
2,6-di-tert-butylphenol
C14H22O an organic compound
SDS says there is less then one percent in what they sell you so whatever it is it doesn't take much
 

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You can throw o-rings in oil for a few days and they WILL get softer, same as fuel only slower. Why you don't use petro distillate products on rubber brake parts. Part of the VOC solvent that leaves all rubber with time to harden it is semi-petroleum based in nature.

I would flex the rings hard to see if they have cracked which comes next, once they are that dry I would buy new ones, you don't bring them back that late in the day. If you see miniscule cracks they will crack when compressed at install and bad things then.

As far as simple swap out for others one can get o-rings everywhere but is the material type suitable for the use there? Most aren't and then there is the thing where many rings are picked with .X differences in size to make one that looks perfect not seal as you only seal by maybe .005" and one missing 2 of that can leak. You can't see that by eye and measuring them is the pits as well.
 

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Ace Tuner
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O-rings from an auto parts place or even Ace Hardware.
You may have better luck at a motorcycle shop that sells and/or services Japanese machines. Seems like American O-ring kits and O-rings usually are too large in diameter.
K&L Supply sells Japanese compatible O-ring kits.

S F
 

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The parts lists like at partzilla used to detail the exact sizes of the o-rings like the bolt sizes too but they seem to have dropped all that to force you more toward buying NOS parts.
 

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My experience tells me that if I have it apart, that is the easiest time to replace them. I Would rather do it then than have to take it apart again. For the little cost why not get new ones? I have found that once they get hard and brittle they will never be as good as new.
 

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Discussion Starter · #17 · (Edited)
I guess I have not been clear. The engine is all apart. I am replacing all the old rubber seals, gaskets, and o-rings. I'm purchasing the OEM parts, many of which are in a Honda Gasket kit. These parts are OEM, meaning they may be as old as the bike. So the rubber parts are old and hard too, but not compressed and deformed like the parts on the bike. I just want to soften and thicken them up before installing. I figured you guys had encountered this as a normal issue on your vintage bikes rebuilds. Guess I was mistaken. I'm doing the wintergreen and alcohol soak method.
 

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If the o-rings are still dimensioned right, I would just install them.
Anything more then full surface contact is enough for an o-ring to work.
 

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These parts are OEM, meaning they may be as old as the bike. So the rubber parts are old and hard too, but not compressed and deformed like the parts on the bike. I just want to soften and thicken them up before installing. I figured you guys had encountered this as a normal issue on your vintage bikes rebuilds. Guess I was mistaken. I'm doing the wintergreen and alcohol soak method.
How do you know that the OEM O-rings are as old as the bike? Just because they fit a certain year doesn't mean that they were made in that year.

Try thinking a little laterally - like - "My bike is still a popular model and Honda keep manufacturing seal kits because they will continue to sell" - that kind of thing.

.....and stressing over O-rings for a 63cc 'motorcycle' is a little over the top IMO.
 

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Discussion Starter · #20 ·
Very true. If they start out hard, they would tend to compress more quickly and lose their effectiveness. But in reality by that time I probably will not be around anyway.
 
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