How to fit seals
Posted: 26 Jan 2003, 22:53

okay, so your seal has blown and you think, how do i do this as cheap as possible.
First thing to do is call the guy's at leisure trail and get one sent over. They cost £20 per side with the carraige.
The rule of thumb is that if one has gone, the other will follow not long after. I bought a set and did them both, results speak for them selves.
Before you do any of this you need to check that you have the following items.
1. A crm250 with upside down forks.
2. A friend to help
3. A bench (preferably with a vice)
4. replacement fork oil (approx 1.5 ltr)
5. old bucket to pour old fork oil in
6. a measuring jug, to measure the contents of your used fork oil
7. a box stand or means of suspending the bike when the front wheel and forks have been removed
8. a selection of basic tools, spanners, hammer, cloths,
So the first thing to do is take off the front wheel.
Once the wheel is off and you have identified which fork leg is leaking you need to remove the plastic fork leg protector and then the caliper (if you are removing the disc leg)
The next thing to do is to remove the headlamp, you will need to do this to access the 10mm bolts on the top yoke clamp.
The headlamp is secured with four bolts, two on each side.
You then need to loosen the top nut (think 19mm) of the fork whilst the leg is clamped in the yokes.
Then get on the floor with a 17mm socket and loosen the nut in the recess of the fork. WATCH OUT FOR OIL. Loosen does not mean remove!
If you are only removing one leg, you can take your measurement from the remaining leg when you replace the unit, if you intend to remove both, make sure that you mark or write down how high the forks sit in the yokes.
With this done, you can undo the two bolts on the top yolk and then the lower set of bolts both 10mm
The fork leg will now slide out.
Take the fork leg to your bench and get your old bucket ready.
With an extra pair of hands or a vice (use gently), undo and remove the large top nut. Then empty the contents of the fork leg into the bucket.
When you think that most of the oil is out, keep the leg upside down and begin to remove the nut in the base of the fork. You should know that this nut is not connected to the fork itself but is threaded into the internals of the fork and must be removed in order for you to take the leg apart.
with the bolt out (which has a needle in the middle) you should now be able to extract the fork internals.
remember the order they came out and place them onto some cloths as they will still be oily.(dont do this on mums new kitchen table cover)
With a screwdriver then gently prise the first \"dust seal\" from the fork leg, this will be slide down the leg and can be left there for the moment.
Inside the leg you will now see the oil seal and a metal wavy circlip. Use your small screwy to remove this and keep it safe.
You will then be able to yank the two units apart.
BE CAREFUL as you may find other small parts coming out which should have come out with the internals.
As you do this the oil seal will be removed as well, as there are metal spacers behind the seal that will not pass through the seal, therefore pushing the seal up the leg.
You can now concentrate on removing the metal ring at the top of the leg which will allow you to remove the two seals that are sat on the leg, along with some metal discs. again remember the order as they have to go back the same.
Get your new dust seal smear a little oil around the inside and place this on first, next comes the oil seal, again remembering to put it on the same way as the old one.
replace the metal discs and the large ring.
you are now ready to reassemble your forks.
You need to guide the fork leg in and make sure that the metal discs are tapped in level, the oil seal can then be put into position for the final push.
I used balsar wood the same thickness as the seal and this worked fine,
Tap away at the seal and rotate the leg until the seal is below the circlip recess, this is how far you have to go down.
With the seal below this level you can replace the circlip, then slide down the dust seal.
The internals then need to be wiped down. dont forget to compress the damper unit as this will contain old oil, and will need to be added to your measuring pot.
With the internals in the correct order you should then feed the whole lot horizontally into the fork leg. A good idea is to do this bit with a friend, one of you with a small screwy and a torch, look down the small hole to guide the unit to marry up with your hole.
if you are very good at this, the bottom of the damper will appear, which is what your bolt threads into. if you do not feel your bolt connect, then the bottom of the damper is not in position.
Once you have this bolt in place it is simply a case of getting it tightened up and refilling the leg with the relevant amount of oil.
you should then tighten up the top nut and 'prime' the fork leg.
You do this by putting the fork leg on the floor and simply leaning over it and pushing it towards the floor like a giant pogo stick. 20 pushes should be enough and you should feel the internals distributing the oil.
Slap back in the yokes and tighten up, replace headlamp, replace wheel,
pump brake lever, and then test gently.
It took me and a friend around 90 mins to strip bike of both legs, clean, replace, refit and test them.
Good luck
Justin
