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MrSteele

Bevel Gear Box cross shaft endplay

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MrSteele

After much grass cutting, working a few days and nights, I am finally able to get back to reassembly of my Landlord. The parts manual for the Landlord shows 2 shims, marked F and G on the cross shaft, F says "as required": Endplay is not discussed, but I found an article here from 2009 that says there should be no endplay on the cross shaft. We have a problem. I cannot add enough shims to make the last 1/8" of endplay go away. I have the shims, but the key for the pulley will not allow more shims to be added. I can fit the key to fit under the ID of the shim, and is the only way I can find to make it work. What am I missing here? I could add shims between the bearing and seal, but that will only give me the same result because of the spacer moving out farther. I guess I will either rework the key, or grind away some of the ID of the shims. I am using thrust bearing races as shims, have .015..030, and .062. Any help will be greatly appreciated, have been cutting my yard with an UGH, Cub Cadet, that is too top heavy to use on slopes to suit me.

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Tom45

The shims go between the right side sideplate and seal in the bevel gear box so that they hold the right side ball bearing against the shoulder in the bevel gearbox housing.  The nut on the right side of the bevel gearbox shaft should keep the shaft tight on the ball bearing.  If shimmed correctly at assembly, normally no further adjustment is needed.  If the nut on the right side comes loose, it can allow shaft movement.  

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TimJr

I know on later tractors, the pulley hub can get worn on the face towards the BGB. This usually happens when a pulley nut comes loose. That will cause end play, and can't be made up for without replacing the pulley and the likely worn sleeve the seal rides on.  Easier to show than explain, and I don't have a worn pulley to show.  

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MrSteele

Sounds good in theory, but, in reality that ain't quite right? Your idea would use the seal housing as a thick shim to hold the bearing tight. In reality, I still have space between the seal and bearing race after installing .068 of the large shims at the outer ID of the bearing/seal area. Those shims cannot be used to take up endplay on the shaft. Such an installation would put a lot of faith into the outer shell of the seal to be a solid shim, which it is not.The nut at the end has no correlation with the shims between the seal and sideplate,, and the endplay adjustment of the bevel gears and cross shaft as best I can tell. I just disassembled again to look at it.With the shims at the seal, I would need more than a 1/4" of solid shim to hold the seal against the outer bearing race, and I am not keen on using the seal as a shim.

I guess the real question I have is how much endplay should the shaft have? As best I can tell, the endplay will be adjusted by adding shims between the spacer and pulley, or the spacer and bearing inner race, then using Loctite on the locknut at the end of the shaft to be more certain the nut does not loosen. Such would allow the pulley to thrust the spacer against the inner bearing race, tightening the inner race against the driven gear.  And, back to the question, How much endplay?

Installing the shims at the seal/sideplate did not change the endplay at all

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TimJr

I have much more experience with 7000/7100 tractors, but I believe the older ones are put together the same way.  You need to have a parts breakdown in front of you.  Starting inside the gearbox, the driven gear (the one on the cross shaft) is up against a step on the shaft (I believe) on the early tractors.  Later tractor cross shafts are the same OD all the way across and the driven gear seats up against ring that gets put on the shaft.  This keeps the gear from moving left as you sit on the seat.  Now, moving outboard or to the right.  You have the ball bearing.  Then you have the seal with the thick spacer ring inside it.  Then you have the shims - usually a thick and a thin one, but can vary.  This all gets bolted up against the inside of the LH frame plate.  Next we have the spacer that slides over the RH side of the BGB output (at least on 7000/7100 tractors.  Then the trans drive pulley slides on.  Lastly, you tighten the nut to hold it all together.  When you tighten the nut, you are trying to draw the cross shaft out the RH side of the BGB, but you can't because of the step or ring.  The gear butts against the inner race of the bearing, which butts against the spacer on the shaft, which butts against the pulley, which butts against the nut.  The shims are pinched between the outboard face of the seal and the tractor frame plate.  The metal spacer ring inside the seal allows the shims to push against the outer race of the ball bearing, which sets your end play.  Way easier to show than explain, but it really is simple.  I was always taught zero end play, but don't make it tight.  You will still have some backlash between the gears, but no end play on either shaft.  Again, look at the parts and the parts drawing for how things stack up.  

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MrSteele
28 minutes ago, TimJr said:

Then you have the seal with the thick spacer ring inside it. 

 

The seal I have, bought new and in a Briggs and Stratton package, does not have the thick spacer ring inside it. It is a normal double lip seal. I am going to attempt to use either hardened washers between the seal and bearing, then shims outside the seal. I do not like using the seal as a shim, so will most likely also shim the inner race between the spacer and the inner race. I have all the parts that came out of it. The old seal was thicker, with a metal inside and outside face. I will either shim as described, or look for a different seal

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MrSteele

Zero Endplay is what I was looking for. Completely assembled, I have roughly 1/8", with all shims available from disassembly. My problem has to be the new seal. Some Ag seals are similar to what came out, will just go looking again. Thanks for the advice on the endplay. 

The parts breakdown for my gearbox does not mention an additional shim between the seal and the bearing, and I have basically ruined the new seal.

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TimJr

Foot dragger guys - need your help on this BGB.  I know the 7000/7100 used a thick ring inside the RH seal.  Must be the early boxes used a different part number seal than the later tractors.  Regardless, no need to reinvent the wheel or do something other than OEM.  They have worked the factory way since 1959.

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TimJr

Does the FDT BGB have a spacer that the seal rides on, or does the RH seal ride directly on the shaft?  I circled the spacer in orange.  The parts breakdowns online don't show a spacer, but the Simplicity service manual does show one, just like the 7000/7100 style.  See attached pic.  I don't know when Simplicity subbed the original RH seal, but there is a part number change.  Maybe they made the sub based solely on dimension and didn't realize the original was metal and needs to be in order to maintain endplay since shims push on it.  I have a couple mid 60's Landlords that someday I will go through, so I guess I would like to know what I am in for if they are that different than the later tractors or if I need to make sure I get a specific type of seal for the RH BGB.

FDT BGB.jpg

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MrSteele

Just went out to look. The old seal appears to be in good enough shape to attempt to reuse. The seal outer ring is twice the width of the new seal, made in China and in a Briggs bag. The old seal has the rubber encased in a "housing", with a steel inner and outer face. The new seal is a standard double lip seal. Will try an ag parts person before reusing the old seal. The old seal and the .068 of shim should solve my dilemma

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TimJr

This is a lousy capture of the current Simplicity parts breakdown for the 3012 BGB.  Parts breakdowns for 9hp LL do show the spacer.  

FDT BFB without spacer.jpg

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MrSteele
2 minutes ago, TimJr said:

Does the FDT BGB have a spacer that the seal rides on, or does the RH seal ride directly on the shaft?  I circled the spacer in orange

Your breakdown is almost a duplicate of mine, just drawn prettier. Yes, there is a spacer. The problem is the seal fabrication change

image.thumb.png.97636deca9ed449e86722aa5fc5dfdd9.png

My breakdown. Below is a pic of the old and new seal showing difference in thickness. I tried to also show the inside of both seals. The old one has a steel inside face, the new one is a basic new style seal


 

Seals.thumb.jpg.48864301069377c0855a09d93162c4b7.jpg
 

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TimJr

What I am wondering is if the OD of the spacer on the shaft is the same between FDT and RBT?  If the OD of the spacer is the same, then the ID of the seal must be the same.  So then, I wonder why the later seal with the thick ring can't be used in the early gearbox?  Maybe the bore isn't the same depth or something.  The gears are different from FDT to RBT, but I think the difference is the ID of the gears??  I have never had them apart side by side, and I haven't had an FDT BGB apart for probably 20 years.  I have done lots of RBT's and to me those are easy.

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Chris727

@TimJr, the FDT gearbox does not use a spacer inside of the seal and the part number change to 157669, did not result in a different seal than the oem ones removed. I had an NOS one under that number I was looking at yesterday as I am refurbishing a BGB for my HB-112. It appeared to be identical to the original. It was just so old and hard that I opted to use a newer one (National seal) now also since replaced by a different variation. 

One Issue I have seen in the last couple of these I have worked on, is the gear has worn against the step in the cross shaft resulting in a worn shaft ( it remains true at the location of the key on the gear as that does not contact the shaft). I have had to file and de-burr two of the crosshafts to be able to slide the shaft through the needle bearing to disassemble the box. I would imagine that this could be a possible source of endplay. I did plan to re-use two of these shafts after filing them and cleaning them up. This particular machine isn't worth the investment of new gears or shafts. 

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TimJr

Someone here must know.  Hopefully they didn't stick us with a bad supercession.  I want to do mine right when the time comes and would rather not have to fudge the end play with shims in places they were not originally equipped.

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MrSteele

I think the problem is that the Chinese do not have any idea as to why the seal was made as the original, which, by the way, I installed in 2002. The older style was still available back then. The new style seal will not work without a lot of shimming, which I can do. However, if I can find some NOS somewhere, that will be far easier, or, if an AG seal is available that works...

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Chris727
3 minutes ago, MrSteele said:

Your breakdown is almost a duplicate of mine, just drawn prettier. Yes, there is a spacer. The problem is the seal fabrication change

image.thumb.png.97636deca9ed449e86722aa5fc5dfdd9.png

My breakdown. Below is a pic of the old and new seal showing difference in thickness. I tried to also show the inside of both seals. The old one has a steel inside face, the new one is a basic new style seal


 

Seals.thumb.jpg.48864301069377c0855a09d93162c4b7.jpg
 

That new seal is useless for its original intended purpose.

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TimJr

The current part number is 2168006SM per the Simplicity parts break down right now.  I wonder when that change happened and if anyone has contacted Simplicity?  Can @Chris727 can I steal your pics that shows the 2 different seals and send it off to a couple of contacts?

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MrSteele

THANKS! I knew my mind was slipping, but, did not think it was that bad. You can understand why I was wondering about endplay by looking at the different seal thickness. There is no way to use the new seal without a LOT of shim cutting and measuring. I can do it, but really would rather not have to

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TimJr

I'm sorry - I just looked back at Chris' post and realized he copied your pic.  Missed your pic up further somehow.  I will update if I can get the pic to someone that might be able to get us some better info on the situation.  Tim

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MrSteele

Just sent you a PM with the pic attached. Thank whomever for vacations. I am leaving town tomorrow, back next Tuesday. Hopefully, can find something in meantime. Maybe a packaging mistake?

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Chris727

Here are a couple pics of the step wear I have been finding.

 IMG_1170.thumb.JPG.ac740eaea76d4d6e25a57c6f166ed426.JPG

IMG_1172.thumb.JPG.96f4bce574d8fee1b86269d8d749babc.JPG

This condition, if anything would bring the gears closer together from what I can see but may result in additional shims being required. 

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MrSteele

Thanks. Until last night, I did not even think about the new seal being wrong, though it was different. I did not like the idea of using the inner bearing race as a way to keep the bearing tight against the gear, but that is an easy way to do it, with hardened washers and/or machine bushings. That might be the Chinese intention. I do have enough, and can get more, hardened washers for the OD of the bearing, and enough shim stock to make what else is needed. That is a lot of work, but would be worth it if that is the only way. 

Just ordered 2 of the seals. I have another BGB to work on when this one is finished!

Edited by MrSteele
Spelling and punctuation

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