Can't break loose a fork drain screw :(

MexicoMike

MexicoMike

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This morning I decided to check/change my Commando's fork oil since it's been some years since I did it. Pulled the left side screw with no problem - drained the oil. Looked great - clean and 150ml. So I closed it up and refilled with new fork oil. Went to the right side - no luck at all getting the screw out. I tapped the screw with a hammer against the screwdriver in the slot hoping the impact might loosen any seizing. Didn't work. Tried heating the surrounding area. Didn't work. I put a crescent wrench on the screwdriver to give me more twisting force. Didn't work. I gave up before stripping the slotted head completely. Based on the appearance and the volume of the oil from the left side, I figured the right side "probably" (?) looks the same as the left and, therefore, it's OK. But I don't like the concept of half-done stuff.

Never had that problem in the 20 years I have owned the bike!! :( Any tips for removing the screw that I didn't try?
 
Mike,
Did you try using an impact driver with the appropriate bit? Sometimes, that's what it takes. By the way, I believe that you should fill the fork with 180cc of oil.

Greg
 
Normally a hammer type impact driver is nest for these issues...though a slot head screw can be more challenging. Heat it with propane good and hot...spittal sizzle etc. On the surrojnding alu. Let cool and try impacter. If it mangles/shears then nothing left but to drill out...ideally with left hand drill bit...sometimes these will grab and remains will unthread from hole. Can try an easyout bit as well.
 
Agree on heat and the (manual) impact hammer - as to the latter, not only do these produce prodigious torque but they tend to come with really high quality screw bits that sometimes get a grip a lower quality bit may not, plus minimizing chances of stripping the screw head.

A little valve grinding compound or other abrasive material on the screw/bit interface doesn't hurt either.

Wasn't on a Norton but I had one of these situations a while back and I ended up doing all of the above PLUS dremeling a slot in the screw head (which was already looking iffy) and using a slotted bit in the impact hammer. Success!

New screws may be in order in any event. Ax me how I know. I have a new set of Kenny Dreers' stainless ones sitting in the parts bin waiting the next fluid change.

Good luck!
 
Yeah - I don't have an impact driver here in Mexico. :( I do in Texas!

I'll try heating again - I didn't get it all that hot; I could still touch it with my finger tip.

I thought the 180cc was for forks that had been disassembled and that 150 was for draining/refilling. Do I have that wrong?
 
BrianK said:
Agree on heat and the (manual) impact hammer - as to the latter, not only do these produce prodigious torque but they tend to come with really high quality screw bits that sometimes get a grip a lower quality bit may not, plus minimizing chances of stripping the screw head.

A little valve grinding compound or other abrasive material on the screw/bit interface doesn't hurt either.

Wasn't on a Norton but I had one of these situations a while back and I ended up doing all of the above PLUS dremeling a slot in the screw head (which was already looking iffy) and using a slotted bit in the impact hammer. Success!

New screws may be in order in any event. Ax me how I know. I have a new set of Kenny Dreers' stainless ones sitting in the parts bin waiting the next fluid change.

Good luck!
Click to expand...
Ha! I have a very old tube of "Diamond dust" screw/bolt gripper stuff sitting in my toolbox...never used it in 30 yrs!
 
MexicoMike said:
Yeah - I don't have an impact driver here in Mexico. :( I do in Texas!

I'll try heating again - I didn't get it all that hot; I could still touch it with my finger tip.

I thought the 180cc was for forks that had been disassembled and that 150 was for draining/refilling. Do I have that wrong?
Click to expand...
Impacters are readily availble from any tool/autoparts place...harbour freight etc. Usually pretty cheap as all the newbies want powered impact guns.

AN had a recent video tutorial out recommended 180cc for forks over the book spec'd 150cc. Supposed to improve things noticeably.
 
GOT IT!!! Thanks to suggestions here - sort of a combination of them.

I do have some impact-type screwdriver bits and an 18V Makita driver/drill (not impact). I found that one of the driver bits fit perfectly in the screw slot. I chucked it into the drill and it unscrewed!!! I couldn't budge it with regular screwdrivers - just damaged the slot. Once the screw was out I filed off the rough edges on the slot and deepened it slightly with a hacksaw. Fluid now changed in both forks - 180ccs!! :)

Again, thanks for the suggestions!!!
 
MexicoMike said:
GOT IT!!! Thanks to suggestions here - sort of a combination of them.

I do have some impact-type screwdriver bits and an 18V Makita driver/drill (not impact). I found that one of the driver bits fit perfectly in the screw slot. I chucked it into the drill and it unscrewed!!! I couldn't budge it with regular screwdrivers - just damaged the slot. Once the screw was out I filed off the rough edges on the slot and deepened it slightly with a hacksaw. Fluid now changed in both forks - 180ccs!! :)

Again, thanks for the suggestions!!!
Click to expand...
On the fork oil I had the same question. I've been using 180cc for clean and dry forks and 150cc for changes. I like the AN tutorials but often come away with "what about" questions.

For future reference:

You need a hammer impact screwdriver, not a powered screwdriver of any type for this. Just an example - lots to choose from: https://a.co/d/3noMx2i

Mine is at least 40 years old and I lost the bit set to I bought this set: https://a.co/d/7qWac8M

It/they have never failed - oil pump screws, sprocket screw, fork drain screws, Norton tach drive screws, Triumph "trap door" screws, and others.

IMHO, you're lucky the powered screwdriver didn't make things worse by destroying the slot or breaking the head off the screw.
 
Peter R said:
Replacing the drain screw with a allan screw will avoid similar problems in the future.
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Sounds good, but those are special screws with short 1/4" UNC threads and a big head. If I remember right, there are only three threads on each. Where to you find Allen screws to replace them and what do you use for the washers then?
 
marshg246 said:
Sounds good, but those are special screws with short 1/4" UNC threads and a big head. If I remember right, there are only three threads on each. Where to you find Allen screws to replace them and what do you use for the washers then?
Click to expand...
Just cut down 1/4 UNC cap bolts to the right length. Use either copper or fibre washers.
 
Mark Savage said:
Do they do them in UNC as well?
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For a drain screw 1/4 UNC are 1/4 BSW as the TPI is the same, only the thread angle is different, 60 vs 55. UNC being much more available is cheaper. UNC and BSW share TPI except for 1/2" so for non critical uses can be substituted.
 
kommando said:
For a drain screw 1/4 UNC are 1/4 BSW as the TPI is the same, only the thread angle is different, 60 vs 55. UNC being much more available is cheaper. UNC and BSW share TPI except for 1/2" so for non critical uses can be substituted.
Click to expand...
I was aware of the same tpi, just not sure that the 5 degree angle difference on only a few threads would be desirable.
 
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