Washer for bolt at the bottom of forks

  • Thread starter Thread starter Reggie3cl
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Reggie3cl

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What sort of sealing washer goes on the M12 bolt that holds the slider to the damper rod?  The parts list just shows 'gasket' and I think the copper washers I have are a bit narrow, ie too small an o/d at 16mm.

I have a strap compressing the fork leg and I think there may have been a smear of oil on the end of the bolt this morning (gonna leave it a while longer to check) so the seal may be no good.

The bolt was a bit reluctant to drop out one time while I was faffing about trying to tighten everything up, but a quick tap with a bar brought it out out complete with a pretty chewed up 12mm (18mm od) aluminium washer.

What should be in there - copper or alu, 16 or 18mm o/d?
 
With respect to the diameter it might be a better choice to go for the 18mm OD. Don't know the torque figures on those bolts, but you might crush the sealing surface in the slider when using a washer with OD smaller than bolt head. Me thinks Aluminium and Copper should both work.
 
I have found copper, aluminium and also Dowty washers in there.
My guess is copper is standard.
 
I use Dowty, but copper is standard I believe.

As for OD - anything bigger than the underside of the fixing's head is wasted anyway, as far as sealing is concerned.
 
OK, another one then: What's the correct torque?  None is given in the manual apart from a general one for M12s which is around the 35'lb mark.
 
The bolt isn't retaining a critical moving part so the torque only needs to be high enough to crush the sealing washer enough to seal it to the bottom of the fork. 15 or so ft.lb. or good and snug should suffice.
 
Grant said:
I have found copper, aluminium and also Dowty washers in there.
My guess is copper is standard.
Click to expand...

never run across the term "Dowty" washer, had to Google it. I have only ever heard that type of washer referred to as "bonded seal" washers, where does the "Dowty" term come from?

for the bottom fork bolt I have only ever used copper crush washers, easy to get, I keep a stock of various sizes in my garage.

for torque on the fork rod bolt, keep in mind the bloody thing has to come back out eventually, be kind to the next person who will have to get it out, wipe some anti seize on the threads before you put it back in and do not go nuts over tightening......

Paul LeClair
 
Maybe something to do with Dowty forks as in Velocette, Scott, Panther....
Washer is copper and I seem to remember about the diameter of the screw head.
Paul
 
Dowty was a manufacturer of all things hydraulic, so their stuff can usually handle serious oil pressures and some parts have transgressed to installations where they are not really needed, which does no harm. There is also a fitting known as a Dowty coupling, which is a device for the quick connecting disconnecting of two hydraulic hoses, via a male and female part, with virtually no loss of the oil.

sort of like a "hoover" is the term used for almost any vacuum cleaner.

I would favour freshly annealed (descaled then  lightly greased) copper washers, but I would also be giving the bolt very close inspection under the head
CLEM
 
CLEMTOG said:
Dowty was a manufacturer of all things hydraulic, so their stuff can usually handle serious oil pressures and some parts have transgressed to installations where they are not really needed, which does no harm. There is also a fitting known as a Dowty coupling, which is a device for the quick connecting disconnecting of two hydraulic hoses, via a male and female part, with virtually no loss of the oil.

sort of like a "hoover" is the term used for almost any vacuum cleaner.

I would favour freshly annealed (descaled then  lightly greased) copper washers, but I would also be giving the bolt very close inspection under the head
CLEM
Click to expand...


Nothing quite like a quick coupling Clem.
Paul
 
I'm pretty convinced I've got a leak free setup now, but I don't know how the sealing face of the slider is - certainly the aluminium washer that came out was pretty chewed up.  I do suspect that 35 'lbs is  perhaps a bit much, but there's no definitive figure in the book.  Anyway, I'm not taking it apart again to look any time soon.

BTW, the Motul 'Factory Line' fork oil really helped the action.  Properly slippy stuff that.
 
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