Replacing fork seals

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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Janet
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Replacing fork seals

Post by Janet »

Having successfully stemmed the major flow of oil from the engine on myG2CSR, and replaced the kick-start spring, leaving a bit of a drip from the gearbox ( I suspect this is not new but wasn't apparent because of the engine gusher ) the dear little thing has decided to start leaking past a for seal. It's timing is perfect as the MOT is due this month and the Jampot looms. Accordingto the sticker on them, the forks are Teledraulic and, if I've understood correctly, they are the same as early heavyweight forks. I hope so because I've bought a pair of seals thinking they'll fit.

I'm planning on starting work on this at the weekend, dismantling the dodgy one first. Before I do, is there anything I need to know that may not be obvious from the manual? Any warnings of what not to do? Is it something I really shouldn't attempt?

All friendly answers gratefully accepted. Sensible suggestions even more so.

Edited by - Janet on 20 Jul 2010 1:26:37 PM
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itma
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Replacing fork seals

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Janet
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Replacing fork seals

Post by Janet »

Ta everso. I did try a search but couldn't think of the right words. M ethinks, should have tried teledraulic instead of G2 or lightweight .
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56G80S
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Replacing fork seals

Post by 56G80S »

Janet

I've dismantled my heavyweight forks more than once (never had to on the 14 CSR) but would recommend making up or getting a loan of a puller (making up is quite straightforward with some threaded rod, some matching nuts, larger washers and an old cap nut).

It makes re-assembly very much easier whereas doing so without it requires considerable strength and a fair dash of anguish.

Johnny B
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Janet
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Replacing fork seals

Post by Janet »

quote:
Janet

I've dismantled my heavyweight forks more than once (never had to on the 14 CSR) but would recommend making up or getting a loan of a puller (making up is quite straightforward with some threaded rod, some matching nuts, larger washers and an old cap nut).

It makes re-assembly very much easier whereas doing so without it requires considerable strength and a fair dash of anguish.

Johnny B
Is this for pulling the fork back up into the yokes? If so, I was given one of those years ago for my G80 (no, I haven't rebuilt it yet ) and it has the smaller diameter forks so, hopefully,the puller will fit.
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Janet
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Replacing fork seals

Post by Janet »

Well, I set to with all the enthusiasm of a turkey near Christmas. I was not disappointed.

First, to remove the mudguard. Yeah, right. The nearside has two bolts fastening it to the fork leg, neither of which would shift. The offside, containing the offending seal, had two studs with nuts on. Neither nut would move but the studs unscrewed. Unfortunately, there wasn't enough clearance between fork and wheel to get them out, so the wheel had to come out first. I hadn't removed it initially because I prefer to do tugging and riving with the bike firmly planted on the ground if possible.

With the stand up on blocks and a board and trolley jack to stop the front from tipping it was out with the wheel. I was confident of doing this bit because I'd replaced the front tyre before the Irish International Jampot.

Now, I'm fairly sure that good practice is to renew fork seals in pairs but in view of 1) the difficulty in removing the mudguard from the other fork, 2) it's due an MOT this week and 3) the Jampot is only 2 weeks away, I made a management decision to support the mudguard and other leg and only deal with the leaky one.

Getting the fork leg out of the yokes required a bit of thumping but nothing excessive. Unscrewing the fork extension was a completely different seafood cooker. With hands installed in rubber gloves I tried grasping the part and turning, bearing in mind I ride a Honda 400/4 which must have one of the heaviest clutches and throttle return ever fitted to a bike, my hands are not exactly weak. Nothing! So then I got out the gas torch to apply some heat. It was at this point, as I set fire to my thumb with the lighter, I began to feel that my anticipation of the difficulty of this job was probably closer to the truth than had been indicated by others. Having extinguished myself, I gave the fork slide a liberal mount of heat, then tried to turn the extension. Nothing!! Thinks. The extension screws into the slider? Yes. So I am correct in heating the slider to try to get it to expand away from the extension inside. Well, it didn't work anyway.

At this point I rang Gary Corcoran, a terribly grand chap in Leeds who had offered to lend me some tools if I needed them. Did he have any other suggestions? Only that I could try some stillsons but they normally damage the bit. However, he had a spare in poor condition ie chrome missing, that I could have if I totally mangled mine. That made me feel better as I then knew there was a spare available that would be totally in keeping with the patina of my machine. I decided that the 18" stillies would be big enough, wrapped the tube with a cloth and applied some pressure. Nothing!!! Ah, to hell with it, I'd give it a bit more force and felt a moment of Triumph (odd because It is a Matchless) as there was movement. Also, if you didn't know better, and without your reading specs, you wouldn't be able to tell what I'd used.

Next, for the seal itself. I set the fork up in the vice, did the pushing and pulling motion, then heated it up, did the violent tugging again with my full weight behind it. Nothing!!!! Things might have been easier if this seal was like the new ones, which appear to be reinforced rubber but, oh no, it was housed in a steel cup. And you know how tightly steel likes to sit in alloy, especially after 40-odd years. SO I did the only thing I could think of. I drilled perforations in the top of it and then snapped off bits of it. I was able to scrape out the rubber and, by tapping in the right place, successfully pulled a bit of the outside inwards, which then broke the grip with the alloy. Back to the tugging and out it popped.

Having got this far, for thereasons outlined earlier, I decided not to take anything further off so I cleaned up the seat and gently tapped the new seal into place. There it now sits, waiting to be re-assembled.
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Replacing fork seals

Post by 1608 »

In case the other slider extension is reluctant, try the following tip, useful for removing such items without causing any damage. Take a strip of rubber 1 ft long ( I use the flat type fan belt ) and nail one end to a piece of wood batten approx 2"x1" x 12" to act as a handle. By wraping rubber around the item to be removed this tool acts like an oil filter remover. Stilsons are designed to tighten onto the material as they grip and WILL crush. Good luck with the re-assembly.
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Replacing fork seals

Post by SPRIDDLER »

Well done Janet. I share your experience of what seem to be half hour jobs for anyone else taking me all weekend including nearly pulling the vice and bench out of the shed door.
It is in fact a good idea to do one fork leg at a time as it does keep the forks/headlamp brackets etc. from falling apart completely.
Anyway, my MOT preparation includes stopping around the corner from the MOT station to wipe the leaking oil off the forks having already given the swing arm a drop of grease from my most excellent 2000lbs/psi Wanner gun to take up any slack.
O.K., O.K. so I should replace the fork seals (again) and I should put oil in the s/arm and I should know better, but having reached 65 neither I nor Marigold do 'Should' any more.
In 33K miles over 6 years she has only once broken down: 2 miles from home when the spark plug blew out of the head plus 3 recoveries for rear wheel punctures - at night, near home and in the rain.
QED

'There is a tide in the affairs of men
Which taken at the flood............'
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Janet
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Replacing fork seals

Post by Janet »

quote:
In case the other slider extension is reluctant, try the following tip, useful for removing such items without causing any damage. Take a strip of rubber 1 ft long ( I use the flat type fan belt ) and nail one end to a piece of wood batten approx 2"x1" x 12" to act as a handle. By wraping rubber around the item to be removed this tool acts like an oil filter remover. Stilsons are designed to tighten onto the material as they grip and WILL crush. Good luck with the re-assembly.
I forgot to mention, I'd tried the rubber strap method before resorting to the stilsons and it just slid round, slowly, but it still couldn't do the business..
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Janet
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Replacing fork seals

Post by Janet »

quote:
Well done Janet. I share your experience of what seem to be half hour jobs for anyone else taking me all weekend including nearly pulling the vice and bench out of the shed door. Thank goodness it isn't just me.
quote:
Anyway, my MOT preparation includes stopping around the corner from the MOT station to wipe the leaking oil off the forks I had considered that, and Gary suggested draining the oil out altogether, which I'd also thought of but that would be naughty.
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