Dahonjack

I got my Dahon Jack in 2007 and rode it a lot and had it outside in the rain, etc. I noticed that it got more difficult to unfold and fold to the point where it's now almost impossible. Is there a way to remove the folding pin and replace it or lubricate it? Anything else that would help?

ShinyBiker

I have removed the pins and bolts then lubricated it with grease (the kind you use in ball bearings). You may not need to remove your bolts it just depends on how stuck it is. Just get it in there with your fingers (I also use some latex gloves). Finally, make sure you wipe off the excess grease or you may get some on your pants.

Dahonjack

Thanks - good to know you can do that, but how did you remove the main pin on the folding hinge - I don't see a pin holding it in and it looked like the only way to get it out would be to drill it out.

jur

Better wander over to Dahon forums to see how to get the pin out. In many hinge designs the pin is held by a grub screw (or set screw) at the middle region. Remove the set screw and the pin should in theory be able to be extracted. There is a hole with screw thread cut into it at the pin's bottom end; put the bike upside down. Screw a machine screw into the hole which provides a gripping location to pull the pin out.

I predict you won't be able to get it out. The pin is stainless steel, while the frame is aluminium. Rain plus contaminants cause a galvanic reaction, forming aluminium oxide, which is larger in volume than bare aluminium. The result is the pin gets more and more constricted. For the same reason, aluminium quill stems and seat posts get stuck in steel frames.

I think your only hope is to thread in a looong rod with a nut near the opposite end, and a sleeve hammer around the rod to provide some very serious extraction hammering action.

You can also try some very penetrating thin oil dribbled in from the bottom and in between the hinge surfaces. Working the hinge to and fro may have the desired effect. I had limited success with this. I was unable to extract the pin.

I think this is a design flaw, or at least a manufacturing flaw.

[edit] I just thought of another way to force the pin out: With a precise thickness spacer with hole large enough for the pin to fit through, this may provide a surface to provide extraction force using the machine screw screwing into the pin. When the machine screw/bolt's head contacts the spacer, the pin will get forced out by progressive tightening of the bolt. With each bit of success, another washer may have to be inserted under the bolt head.

Seira321

I know many people don't recommend WD-40, but would WD-40 work in this case? Spray some on, wait a few minutes, try folding back and forth, and then do the hammering as a last resort. My old bike was outside for many years and WD-40 helped me in the very rusted areas to remove parts off the bike.

I could be wrong though, but just dropping an idea.

Sammyboy

WD40 might work, but it also might well not. The aluminium/steel reaction is pretty powerful, and I've had seatposts I couldn't extract even after making a large wooden clamp and hitting that with a big mallet. The C&V forum guys know about this better than anyone, but with seatposts, the final solution is to melt the post with lye, which is dangerous both to you and the frame, and very unlikely to work in a hinge bolt. The moral of the story is that wherever an aluminium component touches steel, it should be greased, but this is a message to Dahon, not you!

brakemeister

Well Sammy .... about that message to Dahon .... :-)
I could pass it on .... but with a 07 bike which was left in the rain and used a lot .... all the grease in the world applied at the factory will not be there no more ....
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Wd 40 is not the best but cant hurt either ... just get some real grease or oil after you get it working as WD 40 is NOT anything like that. It works great to loosen things up but has almost no long time lubricating values...

you can get any penetrating oil and liberally spary it on the hinge for a couple days in a row... bending the frame as far as it goes back and forth and after a while it should work .......
thor