DIY Repair of plastic shear pins in steering shaft
DaveMueller
Active Jeeper
- Posts
- 269
- Thanks
- 2
- Location
- Ohiopyle, PA
- Vehicle(s)
- '76 CJ5 with an '88 258 from a YJ.
AMC20, D30, D20, T150.
Tools and materials:
High temperature hot melt glue gun
Delrin rod to fit the glue gun (mine was 7/16"), about 12" long
or
A lot of 3D printing filament
Separate the shafts and clean out the old plastic bits.
My glue gun says it goes to 385 degrees, which is theoretically enough to melt the Delrin. 400 would have been better.
I heated the two shafts with a heat gun to prevent the plastic from becoming solid too fast. The 7/16 Delrin was a little small for the glue gun so I couldn't use the trigger. I had to push the gun against the shaft and push like crazy to get the plastic to flow through the tiny hole. I used a 12" piece of Delrin and was pushing the free end.
Heat the shafts while the improvised injection molding machine (aka glue gun) is warming up. Once the plastic runs out of the nozzle, nest the shafts and put a thin rod through one of the holes to keep it aligned (my shaft has two sets of holes, all the way through). Push the nozzle against the hole and force as much plastic in as you can. Let cool briefly then pull the pin from the other hole and do it. I did it from both sides of the shaft.
It would have helped to enlarge the outer shaft hole a little, and definitely counter sink it to better mate with the glue gun nozzle. Enlarging the hole in the nozzle would be good too, but make it kind of useless for hot melt glue.
I don't have access to 3D filament, but I would first melt it down and make a single rod to fit the glue gun. Otherwise, you'll have to feed a bunch into the gun and use something else to force it out.
Overall, it was a success and I feel way better having plastic shear pins instead of a nail or cotter pin or brass etc. The advantage of the plastic is it fills up the space and take the wobble out too.
As usual, I didn't take any photos.
High temperature hot melt glue gun
Delrin rod to fit the glue gun (mine was 7/16"), about 12" long
or
A lot of 3D printing filament
Separate the shafts and clean out the old plastic bits.
My glue gun says it goes to 385 degrees, which is theoretically enough to melt the Delrin. 400 would have been better.
I heated the two shafts with a heat gun to prevent the plastic from becoming solid too fast. The 7/16 Delrin was a little small for the glue gun so I couldn't use the trigger. I had to push the gun against the shaft and push like crazy to get the plastic to flow through the tiny hole. I used a 12" piece of Delrin and was pushing the free end.
Heat the shafts while the improvised injection molding machine (aka glue gun) is warming up. Once the plastic runs out of the nozzle, nest the shafts and put a thin rod through one of the holes to keep it aligned (my shaft has two sets of holes, all the way through). Push the nozzle against the hole and force as much plastic in as you can. Let cool briefly then pull the pin from the other hole and do it. I did it from both sides of the shaft.
It would have helped to enlarge the outer shaft hole a little, and definitely counter sink it to better mate with the glue gun nozzle. Enlarging the hole in the nozzle would be good too, but make it kind of useless for hot melt glue.
I don't have access to 3D filament, but I would first melt it down and make a single rod to fit the glue gun. Otherwise, you'll have to feed a bunch into the gun and use something else to force it out.
Overall, it was a success and I feel way better having plastic shear pins instead of a nail or cotter pin or brass etc. The advantage of the plastic is it fills up the space and take the wobble out too.
As usual, I didn't take any photos.
