Best Slide Out Shear Pin Material?

[SC40QS]

I have the system pictured mounted under the bed in the master bedroom, from the time I got the coach two years ago, it made a clunk clunk clunk sound whenever going in or out.. worked fine though. Until it didn't one day... then it just clunked along and nothing moved.. I tried to move it manually via the little nut on the motor shaft, it was bound up tight..

Being unfamiliar with the system, I went about getting to that unit in a completely backassward way... I took the entire rack out... or moved it so I could access the motor to actually SEE what was going on... turns out, I'd had a broken shear pin since I purchased the unit, it was just lodged in such a way that it continued to function... until that little piece of pin gave out..

So two things here, I did not have to remove everything to get to it, the two shiny bolt heads that go into the motor housing where it meets the rack pinion drive shaft... are all that you need to get to, a little awkward and you'll need to get the wires sorted (cut, resplice in my case).

So, on to the just of the title of this thread.. what's the best material to use for the roll pin/shear pin replacement? It had the coiled roll pin style, which are supposed to be tougher than the standard slotted roll pins that you can get anywhere..

Could you use a brass shear pin??

TIA... wish me luck getting that sucker back together through the small access hole that I managed to take it apart through...

[Bob_C]

Brass is to soft.....our landing gear also used roll pins, and after shearing one, I went to allen head 1/4" bolts and esna nuts....but I had room for the head and the nuts to spin...

[firedoc]

If you go too hard you lose the protection for the motor.

[Alan24601]

I learned a bit about shear pins after working on our Power-gear jacks. I bought original replacement pins from Rev Group and I suggest that is the best solution. Looking at the problem I found a chart for different materials, threaded and not threaded on the internet. Using a threaded rod as the pin substantially reduced the force necessary to shear the pin but does reduce possible motor damage. For high torque items like an electric jack the solid factory pin is essential in my opinion. Our jack fell and was dragging along the freeway. When disassembled I found the welded in pin to be a soft 1/4” threaded rod. Clearly not up to the task and dangerous. Your situation sounds like an inconvenience if it fails. Factory replacement or a solid piece of rod is best. The assembly looks like a Power Gear unit so pins are available from Rev Group.

[SC40QS]

Originally Posted by firedoc

If you go too hard you lose the protection for the motor.

We may be talking about a bit of a different animal. The pin goes into the motor shaft and then sticks out a bit on each side of the shaft, the coupler to the pinion shaft drive is slotted to accept the shear pin sticking out on each side..

This pin is accessible with just the removal of the motor from the pinion drive gear.. down the shaft within the cavity on the pinion drive is yet another roll pin holding the coupler to the shaft and it's not the spiral kind, so, I guess, I'm lucky that it broke the spiral one and not the one that's buried and would require major disassembly.. I'll grab some pix tomorrow but there's no way a bolt is fitting in there, the brass, whether or not too soft, would not work because the pin can't float or it could wind up striking the sides of the cavity and breaking.. Managed to stay awake long enough to get a pic..

[Crankshaft]

You might run into the same issue I did when a gear self destructed on my slide motor. I had to get a new motor. I don't think your're their yet. Who makes the motor? Can you get us all the names and numbers off the motor? There is a place in Missouri that makes almost all the slide motors for the RV industry, mostly Lippert motors. They had every part, including shear pins, except gears. That's what forced me to buy a new motor.