350 New Upper Carrier

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Kaiverol
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350 New Upper Carrier

Post by Kaiverol » Sun Feb 21, 2021 7:38 pm

I am replacing one of the upper carriers on my 350B. I have a new carrier (after market) with shaft and a new bellows seal (JD..yes my heart stopped for a bit). Now that I have familiarized myself with all the parts and how it works, I have a few questions.

I was able to get the old shaft out of the support and removed the old destroyed seal. I see that the new shaft should be pressed in with a distance of 5.410 to 5.430” as shown in manual. Then there should be end play of .004 to .009” once shims in place as required. However my new roller cover plate does not use shims and is sealed with an o ring. As is, I have .030” end play. I assume the play should be as specified to not put too much pressure on the bellows seal. I see the seal can be compressed right around.25” How much should it be compressed when everything is installed? I worry because of the existing play and minor dimensional differences in the two rollers. I also want to make sure that when I install the roller on the frame that it is in line with the rest of the track components. I don’t have a press (yet), so need to tell machine shop exact numbers.

I got some corn head grease, so I will no doubt need to get a proper grease gun so I don’t blow out the seal. Do these seals have pinholes as stated? I sure can’t see any. Finally the seal surface that faces the roller almost seems to be leather. Is that what it is and should it be lubed prior to install?

Thanks if someone can help me understand.

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LeonardL
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Re: 350 New Upper Carrier

Post by LeonardL » Mon Feb 22, 2021 7:19 pm

Your new roller will have slightly different specs to work with. Have the shaft pressed in until it is 5.42 inches, plus or minus .01 inch. This is measured from the inside bottom of the support. Or where the bottom seal surface will be. Usually the shaft will end up flush with the back of the carrier. Not always but usually. Your seal does have a leather sealing surface and I never put any lube on them. You can however and not hurt anything.

After they have installed your shaft, install the seal and lube the shaft and the bushings with some light oil or grease. Install the roller onto the shaft and you should have a plate that then fastens the roller to the shaft. There are two Allen head screws that holds the plate in place. This then should set a preload on your new seal and you don't have to shim anything.

The roller cap you described sounds like an "Oil Lubed Roller" and not one that you need to grease. Although you certainly can fill them with grease if you want to. That is strictly up to you. If you use oil it is usually a one time deal. I fill them with 80 / 90 gear lube.

When you install the cap, there are three bolts that fasten the cap to the roller. One bolt will be fitted in the same recessed area where the center hole or grease fitting is. Leave this bolt out and then pump grease in until it comes out of the bolt hole for that bolt. Spin the roller a couple of turns and check it again with the grease gun to be sure it is full. It should then be full of grease.

If you use gear oil then you can either wait until you have the carrier installed back on the machine or you can do it on the bench by clamping it in your vise or C-clamp it to the bench. You want the roller to be horizontal or like it will sit on the machine. Turn the roller until the bolt hole is at the side middle or is horizontal at 90 degrees to the shaft. What you want to accomplish is filling the roller half way full of oil. I use a squeeze bottle to get the oil inside the roller. Fill it until oil comes out of the bolt hole. Then install you bolt and a pipe plug in the center fill hole.

You should then be good to go. I hope this helps and good luck!! :D
40 years working on JD 350s and other equipment.

Kaiverol
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Re: 350 New Upper Carrier

Post by Kaiverol » Tue Feb 23, 2021 1:51 pm

Thanks Leonard. I will go with oil now that I know the roller is designed for that. None of the three cap bolts connect to the center or internals of the roller. The center plug therefore is the only way to get grease or oil into the roller. Also there is no hole to allow easy passage of oil or grease to the inside bushing. There are channels in the bushing on the thrust plate face as well as the inner bearing surface which is the only path for lube. I suspect even oil will take its sweet time to flow to the hollow center so I will fill before sliding onto the shaft and the top up with the center plug.

Knowing that I don’t need to worry about end play, I will just concern myself with seal preload. After taking more measurements and going to specs, I would have a preload of about .225”. This should be within the available range of the new seal.

Considering how worn my old carrier roller was, the new one once installed should work like a charm for many hours to come. Now I’ll need to better inspect my other rollers and idlers and ensure they are lubed properly.

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Lavoy
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Re: 350 New Upper Carrier

Post by Lavoy » Thu Feb 25, 2021 8:50 am

I have the upper idler seals in stock, $90. I also have low pressure grease guns and ends in stock, $60.
No, there is no pin hole in the seal. Make sure to lube the surface of the seal before installation.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com

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