As of today, I have begun accepting complete rebuilds for MAG series forks. The rebuilds will include complete disassembly and inspection, new main seals, air cap rebuild, refill with Maxima oil, torqued re-assembly and testing.

I do not replace worn bushings or the dust wiper. Both parts are unavailable. Cost - $100

Here's my vintage '87 Wicked Fat Chance by Fat City Cycles with an early Rockshox Mag 20. I ride it more than my modern bikes :) You'll find details to the Air Valve Cap / Top Cap Rebuild Service below.

I've been invited to join another vintage mtb forum. Here is a link...http://www.oldschoolmtb.co.uk/forum/

Hello, I'm a mountain biker just like you and l love riding my vintage mountain bikes. One thing that's been a nagging problem is how to keep my Rockshox Mag 20 and 21 forks running when the air valve cap gives out. Those air caps are no where to be found! After much experimentation with materials, Ive developed a rebuild process. I'm doing this as a service. Send me your air caps complete with the o-rings and I will clean, lube and rebuild them with brand new air seals. I'll be installing brand new heavy duty air seals sourced from an industrial supplier. The service costs $ 35.00, including return shipping payable via Money Order or Paypal.

You can call or text me in the U.S. at (three one oh) 4 niner 8 two 8 for two

Or email me at "xxxbingintheusaxxx at xxx yahoo dot comxx". To send an email delete all the x's, replace "at" with the @ symbol, the "dot" with a proper "."  and no spaces. 

I apologize for the stealthy contact details, but I'm trying to keep spam to a minimum.

UPDATE: I now have an eBay auction for the service. Do a search for Rockshox Mag 20 21

You can find lots of vintage bike pictures and technology in the following links:

http://forums.mtbr.com/vintage-retro-classic/

http://www.retrobike.co.uk/forum/

http://www.dirtragmag.com/forum/forumdisplay.php?f=39

http://www.socaltrailriders.org/forum/workshop/

Happy trails! Bing Trinidad