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9020 final drive rebuild


jlasater

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One or both of the final drives on my 9020 project are making bad noises and/or clunks. Both finals had gear oil that looked like peanut butter and one had a cup of water in it so I suspect the bearings are shot. Are all of the bearings (tapered roller, needle, and regular ball bearing) generally locally available? I'm not sure about the flanged one that rides on the inboard end of the spur gear drive shaft. It's not apart, so I can't take parts to the local NAPA yet.

If I rebuild and reassemble the final drives and need to rebuild the brakes later, can the final drives be taken off as an assembly, or am I going to have to tear everything back down again? The parts manual sort of looks like it will unbolt as a unit.

Edited by jlasater
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The bearings should be available locally. I did a tear down job on my right rear axle drop housing and was able to find what I needed at a few local Agri parts stores.

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  • 2 weeks later...

Fun in progress. The finals came apart very easily, actually. I'm replacing all the bearings as some had obvious corrosion from sitting in water/oil. Fortunately the gear teeth look good. You can see some of the oil in the drain pan. That was after I changed out the *really* nasty oil/water that came out a few months ago.

9020_final%20drive_1.jpg

9020_final%20drive_2.jpg

9020_final%20drive_3.jpg

9020_final%20drive_4.jpg

9020_final%20drive_5.jpg

Edited by jlasater
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So...the bearing with the snap ring that I got that goes on the smaller gear has a snap ring that is a little thinner than the original one. do you guys think that will make much difference? It's used to locate the bearing between the side plate and outside case. I'm thinking that if it doesn't match the gasket thickness, there might be a little room for it to walk back and forth. I'm tempted to locate some thin shim washers to make up the difference.

I'm not sure that the thrust washer that goes on the far end of the gear next to the needle bearing will keep things in line. With that smaller snap ring, it's equivalent to having a thinner thrust washer.

Edited by jlasater
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Actually...I think it'll be ok. I thought the snap ring was too thin because I took the new bearing with snap ring and positioned that snap ring in the groove of the old bearing and it was loose. Mic'd both rings and they are actually the same, so the old bearing groove has some wear.

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  • 2 weeks later...

Well...a minor setback. After cleaning everything up and reassembling the first final drive, the side clearance on the input shaft gear is too tight to the point I can't turn it. Not having a local supply of precision shim washers, I tried using a flap disk on a grinder to thin the shim a bit but just wasn't getting anywhere. So...found some at McMaster-Carr. $13 for 25 packs. Ordered .010 and .020 shims. The original one was about .063. One thing I'm concerned about is that the OD of the shims are smaller than OEM. They will still ride on the machined surface on the case but not with full contact. The OEM ones measure 1" ID, 1-3/4" OD, but the ones at McMaster (and most other vendors) are 1" ID, 1-1/2" OD. I would assume there shouldn't be much side load on that gear as it's just straight cut, but we will see.

I don't know if the sealed bearing with snap ring has the groove slightly off, or if the gasket material used for these gaskets is slightly thinner than it used to be. Hopefully things will go together on Tuesday.

Edited by jlasater
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Where'd you get the sealed bearing with the snap ring? When I rebuilt my drop axles I got them from Napa and they leaked like crazy, bummer is I special ordered them and payed good money for them and they were junk. I ended up finding a temken bearing that has held up very well.

Edited by phillobbezoo
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They are Axis brand sealed bearings. Hopefully that isn't the brand you ended up with. If it is, let me know asap please :-) do you have a part number for the Timken bearing? Did you  make sure to leave the "slinger" washer on that is supposed to keep oil from the bearing?

I'll probably go ahead and reassemble with what I have, but thanks for the heads up on watching for leaks.

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Final drives are both back together and looking good. One .010 and one .030 shim ended up just right. The thinnest one when up against the case, the thicker one against the gear....figuring it would be less likely to be chewed up if there were any tendencies towards that.

One trick I found to  making cleanup (gasket and gunk removal) a lot easier is to countersink all the holes to get rid of any burrs before you start cleaning off old gasket material...sure makes using a razor blade-type gasket scraper a LOT easier. That, and running a tap through all the holes makes reassembly a breeze.

Edited by jlasater
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Nice writeup and pics, thanks for sharing all that.  Will be interested to hear how it gets down the road, er field when you all back together.

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Re-mounted the finals and fenders. Bolted up the tires, and took 'er for a test spin in 3rd gear. Ran great, and now when I roll it around in the shop in neutral, there is no clicking or clunking like there was. So far, I can't find any leaks either. Glad to have this project done.

Next up: Pulling the engine to rebuild the starter.

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  • 2 weeks later...

In cleaning up the old parts and pieces...I thought I'd post the parts I used for the rebuild.

Axle seal, SKF 19220 (sourced through NAPA), $13.76 ea (need two)
Pinion cup-style needle bearing, outboard end of pinion shaft, Koyo MH-16161, $17.51ea (need two)
Pinion ball-bearing with snap ring, inboard end of pinion shaft, Axis 6206-2RSNRC3, $23ea (need two)
Main axle bearings, tapered roller, SKF BR17 (sourced through NAPA), $13.37ea (need four)

The OEM cup-style needle bearings are NLA, but the Koyo's are a perfect fit. Otherwise you have to use a regular needle bearing and a plug.

The pinion ball bearing with snap ring has the snap ring in a slightly different place. The OEM thrust washer used on that side mic's out at 0.063" but caused the pinion gear to bind. Using 0.040" worth of shims sourced from a transmission repair shop worked perfectly. Those bearings are less than half of what the OEM bearings cost.

I sourced the case gaskets from Sandy Lakes. They had them in stock.

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Jeremy, just a heads up on starter, I just had one rebuilt by a man in Howell Mi. that's been rebuilding for years. 

Parts are no longer available he made several so as to fix mine. Supposedly there is a starter that may work but mounting holes are off.

There's discussion on facebook group and you can get part # there, or someone here may have it

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