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 Post subject: Rock Shox Mag 20/21 help
PostPosted: Tue Oct 09, 2012 1:22 pm 
BoTY Winner
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Location: Everywhere & Nowhere
Hi Guys,

I need to remove the lower legs of a set of Mag 21's I have but not sure on the best approach. Does anybody have any guidance or instructions they could pass on for the best results?

Are there any special tools that I need or is it pretty straight forward.

Thanks in advance

:)


Last edited by Giom6 on Tue Oct 09, 2012 9:31 pm, edited 1 time in total.

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 Post subject:
PostPosted: Tue Oct 09, 2012 9:26 pm 
retrobike rider
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Just undo the bolts at the bottom and the preloaders at the top and pull them out easy peasy there elastomers/spring and I'm sure one leg has nothing in it but that might be just the Indy,s and a bad memory. Still forks aren't witchcraft they are straightforward, just keep undoing bolts until something comes off (just keep a note of what came off and where it came from and most importantly what held it on in the first place.)


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PostPosted: Tue Oct 09, 2012 9:39 pm 
retrobike rider
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Location: Yorkshire, England
Chute55uk, Wrong forks.
These are air/oil

What exactly do you need to do ?

LEAVE the oil in, LEAVE the top caps on. Best if the air valves work reasonable.
Take the brace and crown off.
Take the dust wiper off. (small screwdriver on find the bit that looks like it should go in there. twist and lever it out work your way around. top ring of paint usually comes off.
Drop some oil/spray into the bit under it and clean up what you can.
Take the circlip out, careful not to scratch the stanchion, more so if it '94 Gold Alu ones.
More oil on the oil seal there, penetrating around the outside edge if you really need to.
<might be good to leave on a hot radiator laid down for a bit also>
Now wrap the seal area in a teacloth etc..
Find someway to hold the lower legs and pump air into the top but also keeping the stanchion under control.
Pump air in, as much as you need, shouldn't need to go too far over 100PSI , if you do I would stop and try and get some oil/penetrating, heat expansion expansion going around the oil seal and try again.
< think what might happen when 100PSI suddenly blows the oil seal/stanchion away from the lower leg by oil pressure >
You might be lucky and it just pops apart easily at the lower pressure, or even pull apart with no air, but the negative spring usually makes that difficult in MAG21's. MAG20's don't have the spring to worry about.


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PostPosted: Tue Oct 09, 2012 9:41 pm 
retrobike rider
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And ignore what I said. I took my marzocchi,s apart oil only but air? Nah I'm good someone else can do that :D


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PostPosted: Wed Oct 10, 2012 3:43 am 
Retro Guru
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FluffyChicken wrote:
Find someway to hold the lower legs and pump air into the top but also keeping the stanchion under control.


Yep... this is an important point. I almost killed myself with bits of flying fork when attempting this by myself in the man cave. I can just see the obituary... "man found in garage with Mag 20 fork stanchion embedded in brain" :oops:


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PostPosted: Wed Oct 10, 2012 7:33 am 
BoTY Winner
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Thanks guys and thanks FluffyChicken,

Very detailed instructions. I might need to read them a few times to understand them fully :?

I've got the crown and brace off so its the last bit that I need to do. Sounds like it needs a bit of patience and time, which sadly I lack both at the moment :oops: but these are for a special build, so I will follow the instructions, take my time and see how we get on :)


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PostPosted: Tue Apr 09, 2013 2:05 pm 
Old School Hero

Joined: Tue Nov 09, 2010 6:12 pm
Posts: 211
Location: Norwich
Had my Mag 10s apart last night based on fluffy chickens advice (cheers!).

Time for a good clean, new oil seals and lick of paint on the legs...


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