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Elastomer Goo
#1
I took on the job of o-hauling a 1997 Manitou SX (70 mm) fork after gathering all replacement parts. Please don't say Wings. Hindsight, baby. I have it!

On this fork, the 2nd stage rebound elasto's in the right leg melted and froze up the fork. I have managed to get it stripped - even bushing removal was a big chore. Carb Cleaner did a great and fast job of cleaning the gunk off of the stanchions but, there is a lot of goo still inside the slider. I went as far as plugging the leg and filling it with 1 1/2 cans of carb cleaner, letting it soak and attacking with a bore-brush for a 75 cal muzzle loader. No go. The gunk just moves around. I'm frustrated and ready to pour muriatic (hydrochloric) acid in there but I know it doesn't play well with magnesium.

This gunk must come out as it is a bit of a restoration project. Anyone have experience with this?
Wheelies don't pop themselves. (from a QBP fortune cookie)
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#2
(10-24-2010, 02:29 AM)RobAR Wrote:  I took on the job of o-hauling a 1997 Manitou SX (70 mm) fork after gathering all replacement parts. Please don't say Wings. Hindsight, baby. I have it!

On this fork, the 2nd stage rebound elasto's in the right leg melted and froze up the fork. I have managed to get it stripped - even bushing removal was a big chore. Carb Cleaner did a great and fast job of cleaning the gunk off of the stanchions but, there is a lot of goo still inside the slider. I went as far as plugging the leg and filling it with 1 1/2 cans of carb cleaner, letting it soak and attacking with a bore-brush for a 75 cal muzzle loader. No go. The gunk just moves around. I'm frustrated and ready to pour muriatic (hydrochloric) acid in there but I know it doesn't play well with magnesium.

This gunk must come out as it is a bit of a restoration project. Anyone have experience with this?

To be honest with you I do not know anyone here that has tried to rebuild a fork. I know what the bottom end cheap ones look like inside but not the one you are talking of.

Im kind of confused on two things 1. what do you mean, "Please don't say Wings. Hindsight, baby. I have it!" ? 2. How did it melt?
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
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#3
(10-24-2010, 01:46 PM)Bill Wrote:  To be honest with you I do not know anyone here that has tried to rebuild a fork. I know what the bottom end cheap ones look like inside but not the one you are talking of.

Im kind of confused on two things 1. what do you mean, "Please don't say Wings. Hindsight, baby. I have it!" ? 2. How did it melt?

Hey Bill. I have been working on suspension forks since the mid '90s. This Manitou model I am particularly intimate with as it is mine and I've rebuilt it several times. Wings is a company that makes coil spring replacements for elastomer forks but, in order to install the springs I would have to sacrifice the damper cartridge. Not willing to go there, yet.

I think they melted from the summer heat of 3 years in my storage shed. The bike was hung vertical from the front wheel and the mess ran down the right leg and gummed it all up.

As I've never had to deal with this situation, I was just hoping someone out there had (not that I would wish it on an enemy, even). This stuff is almost like tar. It is soft, gooey and Very sticky. As I mentioned, carb cleaner did great at taking it off of the parts that I removed but, the gunk inside the leg just moves around and sticks to another spot.
Wheelies don't pop themselves. (from a QBP fortune cookie)
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#4
I haven't worked on forks either, but I will add that I've found brake fluid to work wonders in some unusual situations as well. I always keep some around just for that purpose.

Steve
Junkyard Tools rescued from the junkyard!
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#5
Stay away from the acid - it will just remove the metal, and leave the organic gunk alone.

I would try acetone - no danger to the metal, but will dissolve most organics.

WARNING: Acetone burns very very easily.
Nigel
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#6
Yes acetone is an excellent cleaner and leaves no residue. Its great to use as the final cleaner. Some others you may try are naphta the magic behind to so called goo gone products , Goo gone is very good. I would highly recommend that next. Also mineral spirits and a bristle bottle brush and than a rag. Another super cleaner is the Berryman carburetor cleaner, BUT deadly to paint and plastics.

Read manufacturers safety info and be very careful .

Cannot believe they melted. Definitely look for a different insert.

BTW I found .22 cal brass bore brush great for cleaning between my motorcycle fins. :-)))
Never Give Up!!!
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#7
Thanks for the ideas, guys!
Bill - I saw your mention of brake fluid but... humm... don't want to chance messing up the paint. Interesting though. I may try it sometime to see just what else it will eat.

nfmisso - Acetone just might be the ticket! I have a gallon of it and use it for many things. Don't know why it didn't cross my mind (or too many years of exposure? LOL ). I will try that next, thx! BTW, the acid was mentioned in a jest of frustration.

George - Min Spirits wouldn't touch it but I hadn't thought of Nap. If the Acetone doesn't do it, I'll give the Nap a try. Hopefully get some time for ME in the shop this weekend.
Wheelies don't pop themselves. (from a QBP fortune cookie)
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#8
Bill - I saw your mention of brake fluid but... humm... don't want to chance messing up the paint. Interesting though. I may try it sometime to see just what else it will eat.

ive heard old timers talk about dumping brake fluid in the spark plug holes of seized up engines, and a week later they will turn over again! they were seized from rust, not mechanical failure, and i would have to think they kept the mosquitoes far away when restarted.Smile
Get on your bad pedalscooter and ride!
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#9
There is a product that is used , sorry can not remember the name, that is specially formulated for tar removal on automobiles. Trying to think what the name of it was, but the stuff worked really well. Now the chemical make up of it may have had acetone in it. Ugggh I will try to search it on google.
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
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#10
So acetone and elbow grease is the answer. I have a long rod with a flat end that works well. I have 2 of these forks that have gone goo on me and need to be repaired. Go to suspension fork parts .com. They sell replacement elostomers. The issue I see with the fork is the damper seals hardening and leaking. That dissolves the elastomers. The uppers will not go wrong, it is always the lower elastomers. I have some pics of one I just rebuilt I will post.
http://www.suspensionforkparts.net/eshop/index.php?_a=viewCat&catId=8&page=1

Here is the link for the elastomer rebuild kit.
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#11
Hi Wveddy. Yes, acetone is my next attempt. Sorry that I haven't updated this thread - working on other folks bikes has been busy! I did get my new stuff from SFP as you mentioned. I just need a 30-hour day. *BIG FAT LIE*

The cartridge and damping parts are no problem. I stocked up back in Y2K when our Answer rep gave me some insider info. I may be able to do 2 more overhauls if I work my parts right. Heck - it will be 15 years old in 2012!
Wheelies don't pop themselves. (from a QBP fortune cookie)
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#12
So you would not by chance have spares of the bottom seal on the dampner would you. I am trying to revive with the old wd40 soaking method. Thus far they have not softened up. I would recommend corking the hole in the bottom of each leg and letting the acetone sit for a while. Try to get the big chunks out first. After that it is just some repeated cleaning. I use denatured alcohol as a final solvent to clean things up. Those sfp elostomers are tough to get on, but seem to work good. Good luck on the rebuild.
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#13
No spares of the lower damper seal, ed. Sorry. That part is one that I toss on a overhaul. Don't like doing things twice. Check out your local Lawn Supply store. You will have to go to the Service Counter. They might have 9 of them in a bin in the shop. I don't have a Make or # but, was told that it was a gasket for the fuel line on a Weed Eater brand weed eater. Looks the same!
I do, however, have a Plano container of valve shims and reeds, felt wipers and such.+
I need some Judy Race hydracoil parts from... 2001?...
Wheelies don't pop themselves. (from a QBP fortune cookie)
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#14
So I have two different types of bottom seals. One is a single blue seal, the other is two black seals. Which one are you suggesting is the weed eater part? I have two complete forks and a third for parts. I wish I had stocked up. I am in the process of doing that on my marzocchi.
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#15
i found an oring that fit pretty well and works. That is about as good as i can do for now. I will just have to key an eye out for leaking. Fork seems to work pretty good. This is a pretty simple fork to work with. if you could get parts, i could keep this fork forever.
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