Fork Leak (Bottom Bolt/Fibre Washer)

MCP

MCP

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I just had the front forks reinstalled this spring, new seals, etc. The right fork started leaking from the bottom bolt/washer (not the drain plug) late summer, the left one is fine. I've tried tightening it, no luck, then tried to take the bolt out to have a look at the washer, no luck, the bolt is just spinning. I can't find any info on dealing with this problem.

Does anyone have any suggestions for this or can you point me in the right direction?
Can I just deal with the problem side only?
Does the fork slider need to be separated from the stanchion?

Many thanks
 
MCP said:
I've tried tightening it, no luck, then tried to take the bolt out to have a look at the washer, no luck, the bolt is just spinning. I can't find any info on dealing with this problem.
Click to expand...

You probably need to preload the damper assembly (by keeping the fork spring compressed) while unscrewing (or tightening) the bolt or the damper assembly can turn with the bolt. The fibre sealing washer '26', however, should be inside the fork leg, between the damper rod tube and the slider.
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MCP said:
Can I just deal with the problem side only?
Click to expand...
Yes.

MCP said:
Does the fork slider need to be separated from the stanchion?
Click to expand...
Not if a little sealant on the bolt thread cures the leakage.
 
Last edited:
" The fibre sealing washer, however, should be inside the fork leg, between the damper rod tube and the slider."

Yes. Sometimes it can flick sideways during assembly if your not careful and end up squashed to one side. The washer on the outside should be an aluminium or brass washer. It can compress a little and seals any leaking.
 
johnm said:
The washer on the outside should be an aluminium or brass washer.
Click to expand...

It's a steel washer because the internal fibre washer is the sealing washer.
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L.A.B. said:
It's a steel washer because the internal fibre washer is the sealing washer.
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Click to expand...
Yes but I actually found a softer washer actually works really well.

But free to go with the original of course as you have more experience.

I just found a softer washer works for me. As the OP found out very often the dampertube just keeps rotating when you try to take the bolt out. And it can be a bit of a challenge to lock it. So now I make sure the thread is perfectly clean and the bolt goes in with no possibility of jaming and rotating the damper. Definitely no sealant on the thread.

Then with the fibre washer inside carefully in place and a soft metal sealing washer under the bolt on the outside it never leaks and never rotates when you remove it.

That's my way of doing it anyway.
 
Last edited:
An impact (rattle) gun works well on getting those bottom fork bolts loose/tight. Of course it needs to be a smaller gun appropriate to the size, or set on low torque, not the sort of thing your mechanic slams your car's wheel nuts home with.

For sealing,you could try a Dowty washer on the outside, ie steel washer with a rubber insert around the hole in the middle.
 
HopperXL said:
An impact (rattle) gun works well on getting those bottom fork bolts loose/tight. Of course it needs to be a smaller gun appropriate to the size, or set on low torque, not the sort of thing your mechanic slams your car's wheel nuts home with.

For sealing,you could try a Dowty washer on the outside, ie steel washer with a rubber insert around the hole in the middle.
Click to expand...
I had this same leakage, same side. Solved without dismantling slider. Replaced outside steel thick washer with a correctly sized dowty sealing washer. I did not have the spinning bolt issue but should do as LAB advises and use some pre-loading on the leg springs to help prevent rotation of damper.
 
If all else fails, there's, IMHO, the correct way. Pull up the gaiter, unscrew the collar, remove the bottom bolt and pull the slider off. Clean the slider thoroughly inside - especially where the fiber washer fits. Clean the bottom of the damper. Put in a new fiber washer being sure it seats. Slide the slider back on and watch when it comes close to home that the washer is not disturbed (looking through the bottom) - usually no problem. Push up on the slider and put in the bottom bolt with the proper washer. Tighten. Push the collar back down and tighten. Push the gaiter back into place.

The actual job takes 10 minutes. Getting setup and finishing probably 30 more (fender, wheel, caliper if that side, etc).
 
marshg246 said:
If all else fails, there's, IMHO, the correct way. Pull up the gaiter, unscrew the collar, remove the bottom bolt and pull the slider off. Clean the slider thoroughly inside - especially where the fiber washer fits. Clean the bottom of the damper. Put in a new fiber washer being sure it seats. Slide the slider back on and watch when it comes close to home that the washer is not disturbed (looking through the bottom) - usually no problem. Push up on the slider and put in the bottom bolt with the proper washer. Tighten. Push the collar back down and tighten. Push the gaiter back into place.

The actual job takes 10 minutes. Getting setup and finishing probably 30 more (fender, wheel, caliper if that side, etc).
Click to expand...
Haha. Takes me longer than that to find the oil to fill it again.
 
marshg246 said:
If all else fails, there's, IMHO, the correct way. Pull up the gaiter, unscrew the collar, remove the bottom bolt and pull the slider off. Clean the slider thoroughly inside - especially where the fiber washer fits. Clean the bottom of the damper. Put in a new fiber washer being sure it seats. Slide the slider back on and watch when it comes close to home that the washer is not disturbed (looking through the bottom) - usually no problem. Push up on the slider and put in the bottom bolt with the proper washer. Tighten. Push the collar back down and tighten. Push the gaiter back into place.

The actual job takes 10 minutes. Getting setup and finishing probably 30 more (fender, wheel, caliper if that side, etc).
Click to expand...
make sure the damper top cap is not worn out.. 061347 X2
 
johnm said:
Haha. Takes me longer than that to find the oil to fill it again.
Click to expand...
I expected someone to say it takes longer than that to put the oil in! That was going to be my opening to explain how to put it in within 10 seconds! Now everyone must guess :)
 
For motorcycle work I've found an impact driver better than a rattle gun. Not so torquey.
 
All of the above good advice . Looking into my notebook I found a way of keeping things internally from spinning whilst tightening the lower damper bolt up . Or untightening the assembly too . Remove the lower fork oil drain bolt . Substitute it with a 1/4 UNC bolt snugged up against the internals . Tighten up . Remove bolt and put oil drain screw back into place . I've never done it , but it's in my notes .
 
Thanks for all the suggestions. A lot to digest.

I've tried the 1/4 UNC bolt and an impact driver, no luck. I'll try compressing the forks per L.A.B.s advice and if that doesn't work I will try Gregs suggestion and post my results when I get it solved.
 
MCP said:
Thanks for all the suggestions. A lot to digest.

I've tried the 1/4 UNC bolt and an impact driver, no luck. I'll try compressing the forks per L.A.B.s advice and if that doesn't work I will try Gregs suggestion and post my results when I get it solved.
Click to expand...
Sounds like the fiber washer is missing or chewed up. I never put them in with any power tool but often take them out with one. If the fiber washer is there and the steel washer is there, then maybe the bolt is not right - maybe too long. See if it will come out and measure that it is 5/8" under head to the end. It's also possible that the bottom of the slider is worn away. You could try adding another washer to effectively shorten the bolt a little.

If that doesn't work and you go my way, test the bolt in the damper before putting it back together to be sure the bolt goes in properly.
 
marshg246 said:
If all else fails, there's, IMHO, the correct way. Pull up the gaiter, unscrew the collar, remove the bottom bolt and pull the slider off. Clean the slider thoroughly inside - especially where the fiber washer fits. Clean the bottom of the damper. Put in a new fiber washer being sure it seats. Slide the slider back on and watch when it comes close to home that the washer is not disturbed (looking through the bottom) - usually no problem. Push up on the slider and put in the bottom bolt with the proper washer. Tighten. Push the collar back down and tighten. Push the gaiter back into place.
Click to expand...
Tried compressing the forks and used a long bolt in the fork drain hole to get the bottom bolt out#18. Didn't work. Looking at your suggestion next Greg, but if I can't get the bottom bolt out at this stage; wondering if these steps will work?
 
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