Frozen Filler Caps on Front Forks

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Has anyone encountered frozen filler caps on the front forks? I have a 1974 850 Commando and want to rebuild the front suspension but cannot get the filler caps to budge. Any suggestions?
Thanks!
Brian
 
You can try heating the tubes just below the top yoke. Having the properly-sized socket and a breaker bar will help, also. The top nuts are fine-threaded and are also used to pull the tubes tight into the tapers in the top yoke. Once you get them loosened, a good smack with a rubber mallet or ballpeen-and-wood block will release them from the top yoke. Be sure to loosen the pinch bolts in the bottom yoke first.
 
You will have to undo the damper rod lock nuts aswell to be able to remove the fork top nuts. I set the bike on the main stand, remove the front wheel/fender and rest the fork legs on a block.
sam
 
Thanks for the suggestions. I'm using a 1 5/16 per the manual. They won't budge at all. I've read the maintenance guide 1000 times to see if I need to undo anything else first, ie bolts at bottom of fork, but all I can see is that it functions primarily as a filler cap and you should be able to remove without having to loosen anything else. The bike had been sitting for 10+ years. I will pick up a good torch and try some heat.

Thanks,
Brian
 
but all I can see is that it functions primarily as a filler cap and you should be able to remove without having to loosen anything else

Yes they should loosen off without any other work, but once loosened you either have to undo the bottom bolt for the damper or move the slider up so the damper rod can be detached from the underside of the filler cap before you can take it out fully. If you do this the bike has to be supported correctly or the front will collapse as the filler cap locates the top of the springs.
 
Thanks Kommando, Would taking the weight off the front help? If there is pressure on the caps especially fine thread, would be an additional force I am fighting? I'll try that tonight and apply some heat. Last resort may be removing front and and taking to a shop, or grinding off chrome and welding large nut on top to apply more torque? I even tied an air wrench hoping the vibrations would free up, but no such luck.

Thanks
Brian
 
I would spray some penetrating oil around the threads several times. Are you using a long handle breaker bar? Your not going to get enough leverage with just a ratchet handle.
 
The spring pre load due to it being on the stand rather than fully lifting the front wheel off the ground is insignificant, your problem lies elsewhere and more force is required, do as Gripper says, anti rust and a longer bar but make sure the bike does not fall over.
 
bsereda said:
Has anyone encountered frozen filler caps on the front forks? I have a 1974 850 Commando and want to rebuild the front suspension but cannot get the filler caps to budge. Any suggestions?
Thanks!
Brian
Did this bike sleep out in the rain for a couple decades?
 
Never come across them as tight as that before need to ask the obvious IE you are turning them anti clockwise?,I'm surprised a windy spanner wouldn't shift them ! Maybe a previous owner glued them up with something? Try some accetone mixed with atf , Either way heat will probably resolve this issue ,it's really last resort stuff welding nuts on top of the bolts but this should work because heating up and letting it cool very often will break a corroded thread free good luck with it
 
Take the clocks out of their holders if you need to use lots of force. It is easy to slip and crack the glass. :shock:
good luck.
Cheers,
Thomas
 
230 lb. of torque , you better make sure if the nut doesn't break free it might twist arms around like a squirrel. But yes , :shock: shock power.
 
bsereda,

I'd try a breaker bar, at least 3/4 inch, before using an impact wrench -- especially if you plan to re-use the fork tube top bolts. Assuming the bolts are stock, an impact wrench may damage the chrome and/or mar the bolt head angles.


Solvents, as suggested in previous responses, may damage paint on the instrument cups, the triple trees, the gas tank, the frame, etc. Especially acetone.


If you haven't already, I suggest you remove the gas tank and sidecovers and move them far from the bike before commencing with any efforts.



.
 
If your socket is a good tight fit, there should be no damage using an impact gun, especially for loosening things. The hammer-actuated hand impact is normally for much smaller fasteners and may not be any better than the socket and breaker bar. Where they are really handy is for screws that may be easily damaged by screwdriver slippage. The fact that you whack the tool with a hammer lends positive engagement that would otherwise not be available.
 
Thanks to all for the suggestions. After some heat from a plumber torch and a breaker bar, I was finally able to remove the caps. My guess is that the prior owner took the time to either pressure wash or hose the bike down with some kind of water based cleaner. Over time, they must have just rusted in place. Delicate operation due to the proximity of the gauges.

Thanks Again
Brian
 
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