Cannot remove the MK3 swing arm cotter pins

Status
Not open for further replies.
2WheelsUp

2WheelsUp

VIP MEMBER
Joined
Apr 9, 2022
Messages
76
Country flag
I'm trying to remove the swing arm on my MK3 and cannot get the cotter pins out. My understanding is that they can be pushed out by tapping on the threaded end. They won't budge not matter how hard I hit them. The area under the cotter pin cap is very clean, no corrosion or rust that I can see. I've tried WD-40 to loosen them as well as applying heat from my heat gun. I removed the welch plugs to see if I can move the spindle a bit, thinking they might be jammed against the slots, but the spindle won't move either. Any ideas?
 
Up the anti, use a bigger hammer, ideally a copper/hide hammer, using the copper end so it won't slip. You will destroy the threads on the cotter pins but so long as you've got it moving, they will come out. If they are still stuck and the threads are now looking like a mushroom you will have to drill them out. Cut off the mushroomed over end to get a flat surface and see where the actual pin diameter is, center punch the pin in the center as accurately as possibly and drill half way with a 3mm or so drill. Depending on how accurately this hole is then open it out to say 5 to 6mm. Try to then punch the pin out. All this is much easier with the cradle/swing arm removed and on the bench.
The last Mk3 swinging arm i removed the PO had belted the cotters in with the swinging arm pin misaligned. He had hammered the SA pin in, and deformed the end so much so that the flats on the SA pin, that the cotters engage with, didn't line up. He then hammered the cotters in!
I still managed to get them out.
 
Don't use WD 40 it's a water dispersant
Use plus gas or some over penetrating oil
Did you undo the nuts until they were level with the end of the thread before hitting them?
The larger the hammer the better
Think of it as pushing the pin out with the momentum
Rather than pecking at it with a small hammer that will mushroom the thread
 
Use an ALUMINUM drift, and a THREE POUND hammer.
Lay the bike over, so you can get good swing
 
WD-40 is not to be used. 3 in 1 Professional penetrant in a spray can or other penetrant is to be used. Heat her up yes. If you haven't buggered the threaded ends ( x 2 ) yet there is another old trick . Screw the nut back on with as much tread engagement as possible , then back it off a turn . Then hit the nut hard with a small sledge , not a hammer. See if it moved enough to take up the one revolution of thread gap. Then celebrate with a beer that it moved , back off the nut another full turn and smack the nut again . Keep going , you get the idea .
 
What everyone else said and MORE heat - propane torch - aim for the metal around the pins only. Alternate with penetrating fluid and heat. Have an extinguisher ready and of course, the gas tank and carbs off. If powder coated it will make a mess. If paint, easy to fix.
 
Thanks for the advice. I was going to remove the engine/gearbox using the technique where you lay the bike on its side after removing the swing-arm and forks. At this point, everything is stripped except the swing-arm, perhaps I'll still try to do that so I can get better access to hit the pins with more force using a heavier hammer. The frame is going to be re-finished so no worries about damaging paint with a heat/torch. Things had been going pretty smooth up till this point.
 
2WheelsUp said:
Thanks for the advice. I was going to remove the engine/gearbox using the technique where you lay the bike on its side after removing the swing-arm and forks. At this point, everything is stripped except the swing-arm, perhaps I'll still try to do that so I can get better access to hit the pins with more force using a heavier hammer. The frame is going to be re-finished so no worries about damaging paint with a heat/torch. Things had been going pretty smooth up till this point.
Click to expand...
If they really are siezed that badly
Heat will be your friend
 
I just re-read the title... reminded me of my Dad, he used to say: 🗣️ "You can and you WILL!" (in response to " I can't") 🤔
 
"You can and you WILL!" (in response to " I can't")

Oh yeah, taking off the gloves now, bringing on the heat and the sledgehammer!
 
2WheelsUp said:
"You can and you WILL!" (in response to " I can't")

Oh yeah, taking off the gloves now, bringing on the heat and the sledgehammer!
Click to expand...
Love it! 💪👊

Like a Buick being hit from behind with a Pinto. Dented trunk.
Versus the same Buick hit by a loaded Mack dump truck. The Buick WILL MOVE🤣

Don't forget the aluminum/alloy drift!
1" round bar cut 12" long is a good one to have on hand.
 
  • Like
Reactions: baz
I was able to get the cotter pins out. Once I removed the gearbox and engine from the frame, I flipped the frame upside down so I could deliver a solid blow to the pins. One whack with a hand sledgehammer and they came out... not heat necessary. Thanks for your help. Now onto removing the bearings from the steering neck and removing the bushings from the swing arm.
 
2WheelsUp said:
I was able to get the cotter pins out. Once I removed the gearbox and engine from the frame, I flipped the frame upside down so I could deliver a solid blow to the pins. One whack with a hand sledgehammer and they came out... not heat necessary. Thanks for your help. Now onto removing the bearings from the steering neck and removing the bushings from the swing arm.
Click to expand...
Good job.
 
2WheelsUp said:
I was able to get the cotter pins out. Once I removed the gearbox and engine from the frame, I flipped the frame upside down so I could deliver a solid blow to the pins. One whack with a hand sledgehammer and they came out... not heat necessary. Thanks for your help. Now onto removing the bearings from the steering neck and removing the bushings from the swing arm.
Click to expand...
a good example of a bigger hammer, CORRECTLY applied, doing the job.
 
  • Like
Reactions: baz
Status
Not open for further replies.

Similar threads

Beaneater
  • Locked
Cannot remove the Crankcase Strainer Drain PLug
Replies
14
Views
1,340
70enfield
7
Back
Top