Wrist Pin tolerance

[hardpan99]

Does anyone know the wear tolerance of the McD #7/#9 wrist pin? Mine is 0.985″. It seems a bit sloppy with a new M2078 bushing that has an ID of 1.005″. Also, is it easy to replace the wrist pin if needed?

[Jay]

I have gone to replacing all wrist pin bushings with a heavyduty bearing made for the purpose because of the slop I find even with a brand new bushing. The bearings take away all the slop and make the mowing much smoother in my experience. Several shops sell them. Jay

[Donn Hewes]

I have a couple here that measure 1.00 spot on and they are not new, but not well used. I thought I had one unused, but I must have already put it in a mower. I also use the bearing plates on my pitmans. But if you have a badly worn wrist pin it seems to me it will be loose with that bearing just as it would with the old bushing. Usually it was the bushing that was worn, so changing the pitman plate or changing to the bearing would also get rid of that slop. But not if the wrist pin was truly worn. With a shop with a press they are not that hard to change. Grind off the back – press out pin. Press in new pin and set it. They are readily available from mower parts dealers.

[Author]

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