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fork seal replacement

Posted: Fri Nov 25, 2022 12:44 pm
Author: deka
Looking to replace the fork seals on my GPZ11. i have done this on the z900 and managed to obtain the correct tool for the damper rod.
However the question is and i haven't heard of this before so it may be a joke things but thought i would ask so don't shoot me down.

I read that you can change the seals without having to remove the stanchions (fork-legs) and basically remove weather seals and the circlip and you can leaver them out
of course i am assuming that the whole of the fork itself is removed from the bike so that you can slip the new one done the stanchion and it saves dissembling the whole lot
if only the seals are to be replaced.

I kinda sounds a bit too good to be true is this possible or has someone been pulling a fast one

Re: fork seal replacement

Posted: Fri Nov 25, 2022 3:01 pm
Author: warren3200gt
It can be done if you can get a lever between the seal and the stanchion and then under the outer lower edge of the seal. That's a big if and risky of scratching the stanchion.
The other way to do it without disassembling the fork leg is to screw self tapers with a washer on them into the seal. You can then get a forked lever under the washer and against the top of the fork leg. Work your way around several self tapers a little at a time. It'll come out eventually.
However, doing it this way doesn't allow to clean and service/check all the damper parts.

Re: fork seal replacement

Posted: Fri Nov 25, 2022 4:08 pm
Author: moizeau
Just done this on mine. Having had it stripped and seen the bits I think you could. The way I would think it's possible would be to remove the dust seal, then the clip, washer, then use 2 or 3 drywall screws in the fork seal at equal distance. They would cut through the seal then when they hit the washer underneath would lift it off.
Having said that, it is just as easy to pull the forks apart. Just be aware of the placement of washers/springs especially 3 little ones that look the same at the bottom. They're not, 2 are flat and sandwich a deformed 'spring' washer.
IMG_20220924_112733_9.jpg

Re: fork seal replacement

Posted: Fri Nov 25, 2022 5:37 pm
Author: Al
There is a simple tool that you can buy that is designed to remove dirt / flies which have lead to temporary leaks on fork seals. Looks like a slither of soap! Maybe thats where the confusion has arisen?
Not suggesting this is a good idea but you may be able to pop them out with short sharp blasts from a compressor through the air valves.
I would want to drain the oil first and make sure they are fully extended or risk getting a smash in the chops, cooled down with a bath in 20W sludge :D
AL

Re: fork seal replacement

Posted: Fri Nov 25, 2022 5:44 pm
Author: moizeau
If you're going to drop the oil, may as well remove the bottom 8mm hex head and use the tubes as a slide hammer to remove the seal, after the clip has been removed.

Re: fork seal replacement

Posted: Fri Nov 25, 2022 6:32 pm
Author: DeadZedDave
C7C61D79-10D1-45BA-BE82-E4FD227B0775.jpeg

A picture from a genuine period manufacturers workshop manual (not Kawasaki)
The manual says remove the fork leg, take the top cap off and drain the oil, then fill the leg completely to the top with ATF/Hydraulic Oil and put the cap back on tight. Remove the dust cover, circlip and washer. Put the leg int he contraption in the picture. (I would recommend a full face crash helmet at this stage)
The contraption looks like there is a heavy-ish metal plate top and bottom, all connected together by 4 lengths of rod and there’s an old car scissor jack at the bottom - the idea is that the jack forces the fork to compress and the internal oil pressure forces the old seal out……. Simples !
I never tried this but I thinkI’d want some additional means to stop the fork leg slipping out sideways under pressure but this is what a Japanese manufacturer printed in a manual in 1979…..
You’d be a braver man than me to attack a 40 year old fork seal with a lever bar or some self tapping screws without first removing the stanchion (chromed bit) - too much risk of damaging that 40 year old chrome on the fork leg.
Moizeau suggest a solution which sounds pretty safe though.
Please let us know how you get on !

Re: fork seal replacement

Posted: Fri Nov 25, 2022 6:56 pm
Author: ADRIAN H
Some oil seals just pop out. Others take a bit of effort, would not want to try and prise them out with the stanchions in place.

The car jack method looks like it could work. Could also lead to a lovely mess over everything within a couple of yards - Think I'd stick to the full stip down method myself, then you can inspect everything whilst its apart. :D :D :D

Re: fork seal replacement

Posted: Fri Nov 25, 2022 9:05 pm
Author: DeadZedDave
.....you could always put a clear plastic bag over the compression contraption and pull the visor down on your full face helmet .... should keep oil spray down to a manageable level HA HA...

Re: fork seal replacement

Posted: Sun Nov 27, 2022 7:51 am
Author: wilsonsjw11
The conventional way is best with the correct tool to hold the nut in the leg but nearly every pair of forks that I have stripped show evidence that the seal has been attacked with a screw driver rather than a seal hook to remove the seal.Once removed the old seal can be used to fit the new part in place with the aid of a rubber mallet.
Regards
Steve

Re: fork seal replacement

Posted: Sun Nov 27, 2022 7:39 pm
Author: gray
my tuppence worth.
I feel it's better to strip the whole fork, cos then you can replace the oil, you can make sure the same amount's in each leg, you have the opportunity to change it to the SAE of your choice, and you can roll the 2 fork legs against each other to see if there's any fractional bend in them and you can flush out any old debris/ gunk from the bottom of the legs.
slacken off the fork top nut and the bottom Allen bolt while the fork's still held tight in the yokes.

Re: fork seal replacement

Posted: Mon Nov 28, 2022 2:10 pm
Author: deka
thanks guys i plan on dissembling them but had just read you could do it intact and was curious thanks again