Bearing Fit

hotratz · August 25, 2009, 02:32:40 AM

I'm replacing the ring gear bearings in the finals on my OC-4 and have a couple questions. First, when I removed the inner bearing from the ring gear shaft I found a .130 spacer behind the bearing. My diagrams do not show this spacer. Is this supposed to be there? Also I noticed that the shaft had been peened to expand the metal under the bearing to make it fit tighter. I'm wondering what the fit is supposed to be. Is this a press fit or was it supposed to be a slip fit. Does anyone have the proper dimension for this shaft?

hotratz · August 26, 2009, 06:33:06 PM

OK, how 'bout this...Has anyone ever changed a ring gear inner bearing and if so did it slip off/on or was it stuck on there pretty good.

John Schwiebert · August 27, 2009, 12:29:38 AM

Do you have a picture of everything that goes on that shaft LESS gears? The parts book call for shims as needed naturally in three different thickness, plus a thrust washer spacer. Is that what it is and it is wore out since there are no oil grooves? Also I leave tomorrow evening and I will be gone for a week so if you post picture(s) and I don't answer I ran out of time.

hotratz · August 27, 2009, 02:57:13 AM

John, I've accounted for everything that came off my shaft except for the spacer shown in the picture. it was located behind the inner bearing cone, last thing to come off the shaft. It doesn't show up in my parts book diagrams.

My most important question is the type of bearing to shaft fit called out for the inner bearing. I'm wondering if it was originally supposed to be a slip fit but the previous owner thought it was too loose when he pulled it off and that would explain why there are punch marks on the shaft to expand the metal to make it a press fit. I need to confirm what the spec is for the shaft diameter so I can determine what the fit should be. The old cup showed a lot of fretting like the pre-load was way too tight. That's why I'm suspicious that the punch marks were mistakenly created and it was supposed to be a slip fit all the time.

Robert Barbour · August 27, 2009, 04:37:03 AM

It should be a snug fit, slid on by hand with no slop. I have a new OC 4 housing with shaft, I will measure the Diameter of the shaft on the weekend and post for you.

hotratz · August 27, 2009, 06:15:07 PM

Thanks Robert, I talked to Landis this morning about the fit and the mystery spacer. He confirmed it is a slip fit and said sometimes when a previous bearing had been spinning on the shaft it would eat into the casting wall requiring a spacer with the new bearing to space it back out so the ring gear wouldn't interfere with the inside of the casting. If it was spinning I can't confirm that it ate into the casting wall. It doesn't appear that way in the picture. I do see evidence on the outer cover that the ring gear was pushed out enough to slightly scrub the inside of the cover so I'm thinking the spacer wasn't needed. I'll give this a closer look. I have yet to pull the other side apart other than pulling the cover to see what's been done over there. I'm going to anyway because it doesn't feel like there is enough pre-load on the opposite side.

Robert Barbour · August 31, 2009, 03:50:21 AM

I measured the shaft, 2.002 to 2.003 and 7 and 1/4" long. That will give you an idea of how much yours is worn. I have seen people set the bearing in place with epoxy on shafts worn like that. If you do that, be sure to install the hub and outer bearing until the epoxy sets so the bearings are in alignment.

hotratz · August 31, 2009, 01:24:51 PM

Thanks again Robert, I worked the shaft with a file and emery cloth to take it back down to spec. I patiently removed material until I could work the bearing on without hammering it on. It fits nice and snug and the spacer wasn't needed at all. Got it shimmed to produce a bearing pre-load of 2.8 lbs of rotating torque measured with a digital fish scale off the teeth with the nut torqued to 200 ft. lbs. Feels a lot better than it did before.