3AJ Forks - Reassembly tips
 

Hi,

I'm replacing the seals on my forks and have done the first part of the job. I now have two fork legs looking like exploded diagrams in the garage. Next weekend I'll be putting them back together, and I've got a couple of questions:

How do you tighten the Allen bolt that holds the damper rod to the bottom of the fork? I was expecting to be able to use an Allen key with a really long extension right down the fork to stop the damper rod spinning, but the top of the damper rod has not got a socket in the top of it. I was planning to either jam a broomstick down the fork into the top of the damper, or put it all back together (- fork oil) and back on the bike, then get my dad to sit on the handlebars to compress the forks while I torque them up. Would either of these work?

Secondly, on my forks, the washers that sit just beneath the oil seals on my forks are concave - it looks like they were cut out of the side of a funnel. Is this normal, or did I knacker them as I used the inside bit of the fork to pull the old seals out like a slide hammer?

Many thanks,
Ralph

(p.s. My learnings so far: When removing the dust seals, there is a metal ring bound to the outside of the seal that sits on top of the fork lower. To remove the seal, drive this ring upwards off the fork lower. It wasn't obvious to me, and now I need to wait a week for new dust seals before I can put it all back together!)

frks frks
 

He VT,

1. Concave rings - yes, normal. Avoids that the rings interferes with the sealing lip.
2. To install the large Allen bolts, clean the threads of the bolts and the damper rod thoroughly. Then, normally, with everything installed, you can just tighten them. If not, the broomstick or Daddy method might work. Another one is, assemble the leg without oil but with sprng and top cap. the spring impedes (a bit) moving of the d-rod, so you can torque the bolts.

Remark: to remove the seals, you can also blow compressed air in the forks; the seals pop out then when lucky. This saves total disassembly.

GL
A

Hi Aukeboss,

Thanks for the advice and reassurance. The compressed air idea is pretty nifty. I'll have to remember that one.

VT

If you use an airtool, the bolt will go right in :)

Otherwise you can use a "square" pipe to hold the nut from inside, thats what i did on mine. The pipe is 25x25mm and has been sharpened in the end to fit. 23x223mm pipe should be perfect. On my mates we use airtool, but i managed to tighten one of them by hand, with some fastmoving turns/notches. Otherwise you can weld (m16) a nut on a rod, and use that.

http://peecee.dk/uploads/062009/5.JPG

I've used the Broomstick method many times over the years, with great sucess!

If the damper bolt & WASHER ain't tight & sealed well, fork oil WILL leak!

Cheers Jan, but my damper rods don't have the machining on the inside for the box section to sit in.

In the end, I gave everything a good cleaning with hot soapy water then a really good rinsing with cold water then final rinse with lighter fluid (I figured nice clean petrol without the nasty additives would be teflon-component friendly). Once it was all nice and clean, I reassembled the forks with all the springs in but without the oil. The this held the damper rods firmly enough that I could tourque the allen bolts (with nice shiney new copper washers Pigford!). No broomsticks or dads needed!

Once tourqued up, I took the caps off, springs out and filled up with oil (note: the 517ml in the manual is per leg), put the caps back on and put the whole lot back on the bike.

Incidently, reassembling forks has to be the most satisfying job ever - everything is clean, an interference fit and slides together sooo nicely. Plus, once the skanky gravey has been replaced with nice new oil and the mounds of crud removed the forks are much plusher. Result.

Thanks for all your advice,
VT