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Discussion Starter #1
Debating whether to change these or leave them alone. Have my skid out for shock service. With 6800+ miles, every single idler wheel bearing is smooth as silk. So I can't see why the drive bearings would be any different. I can't fee any play in driveshaft. But with the brake rotor, it's hard to feel whether bearing is rough by turning the shaft by hand (the 1.75" track doesn't help much either.

It looked like the retaining seal was lose.. i pushed it back into place. But I'm guessing i can't remove the retaining plate inside the tunnel w/out the caliper and such falling off on the inside?

Any good ways to get a better look/feel for the bearing condition? I'm not about to pull them and replace them "just because".

thx
 

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Im planning on pulling mine just because.
6500 miles on my 17xf9k.
Better to do it now than a month into the season is my thinking.

The orange 14 ZR7k to the left in the photo is next.
That's got something like 7800 miles on it.



Jeff B In Maine

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Discussion Starter #6
I’m doing mine at 4000 miles because my shaft was spinning inside bearing. So replacing shaft and bearing in caliper. Doing the chaincase side as well while I‘m at it.
Ok.. but how did you know the shaft was spinning inside the bearing?
Can you change that bearing w/out changing the bearing in the chaincase?

I know what everyone is saying here. I'm not asking if I should. Replacing these "just because I have the skid out is like saying I should replace the brakes on my car because I have the wheel off. Pulling the driveshaft is a MUCH larger job than dropping the skid. I changed the driver in my 2012 (2.52 to 2.86)... not fun.

In my experience, replacing bearings that are in good shape is asking for trouble. Can't tell you how many times I've bought new bearings didn't last (i.e. my truck - 2 years, 30k miles and the replacement OEM bearing was bad).

I'm just looking for tips on how to check them w/out pulling everything apart.
 

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do not buy china bearings ! get good quality replacements, at motion industries , and keep work clean. no dirt or sand .
 

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I would at very minimum pull the caliper off and assess the bearing and driveshaft surface and re-pack if good or replace. Last Winter I left everything to the last minute and did not get to checking that bearing as I had wanted to. Driveshaft was rock solid no movement or slack in the bearing I said to myself “I will be good”. About 300 miles later the bearing disintegrated a week before my annual sled trip and driveshaft is on national back order - learned a lesson and still kick my self in the ass.
 

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I would at very minimum pull the caliper off and assess the bearing and driveshaft surface and re-pack if good or replace. Last Winter I left everything to the last minute and did not get to checking that bearing as I had wanted to. Driveshaft was rock solid no movement or slack in the bearing I said to myself “I will be good”. About 300 miles later the bearing disintegrated a week before my annual sled trip and driveshaft is on national back order - learned a lesson and still kick my self in the ass.
How many mules on your sled?

What year and model?

Jeff B In Maine

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Ok.. but how did you know the shaft was spinning inside the bearing?
Can you change that bearing w/out changing the bearing in the chaincase?

I know what everyone is saying here. I'm not asking if I should. Replacing these "just because I have the skid out is like saying I should replace the brakes on my car because I have the wheel off. Pulling the driveshaft is a MUCH larger job than dropping the skid. I changed the driver in my 2012 (2.52 to 2.86)... not fun.

In my experience, replacing bearings that are in good shape is asking for trouble. Can't tell you how many times I've bought new bearings didn't last (i.e. my truck - 2 years, 30k miles and the replacement OEM bearing was bad).

I'm just looking for tips on how to check them w/out pulling everything apart.
No real good way to tell. Some say to put arm up and try to move shaft. Others say c clip by rotor will be real tight and won’t move freely because rotor and being pushed against it. I think your shaft has to be very worn before those symptoms show up. I never experienced any of those. I already had my chaincase apart for spring preventive maintenance (four strokes got a lot more going on in the chaincase to check over) so I figured I would check it before putting everything back together.

You can change just the caliper side and leave the chaincase side alone but if the shaft is spinning in the bearing then your shaft may be too worn to use, maybe. Inner race of bearing is harder metal than shaft so shaft wears more. If shaft isn’t too worn a new bearing with the Barn of Parts shaft saver may be all you need. Easiest way is to remove skid so you can get weight off of drivers, then unbolt three bolts holding caliper on, remove c clip by rotor and then wiggle rotor and caliper off together. Rotor can be a pain to get moving across splines on shaft. Took me a while to get it. Once caliper is almost off shaft, rotor can be removed then caliper. You can leave brake pads on. Now my gears were already off on the chaincase side so my shaft kept trying to slide out of chaincase. That is the way it comes out when removing.

Some guys leave caliper bolted on and split the caliper to get rotor off. This of coarse involves bleeding brake system later and brake fluid can damage painted tunnels. Once they have front half the caliper off and the rotor, then they check for play by moving shaft up and down in bearing.

By removing whole caliper you can measure diameter of inner race of bearing and diameter of shaft. That is of coarse what I did. Can’t remember the measurements but my shaft was too worn. This whole set up is dumb because it is a slip fit for that bearing and drive shaft. Not locked in in any way, so shaft spins in bearing instead of moving with bearing.

Some have been lucky and have found no or little wear when checking. I wasn’t so lucky. No real easy way to check unfortunately. Lots about it on TY forum. I went with a new shaft, some get their old one built up and machined down.
 

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do not buy china bearings ! get good quality replacements, at motion industries , and keep work clean. no dirt or sand .
Funny, Motion Canada is where I ordered my bearings from, Canadian division of Motion industries. Went with SKF. They are made all over the world so I will have to see where they were made when they show up this week. I wanted Koyo or NSK but wait times were longer to get them than I wanted. Nachi told me sealed bearing was only good to -20c (-4F).
 

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How many mules on your sled?

What year and model?

Jeff B In Maine

Sent via my US Cellular rotary dial device.
7450 miles 2015 ZR 7000 El Tigre when the brake side bearing blew. Considerable wear on the driveshaft bearing surface. I did not even know it had happenned except for the odd noise coming from the front track area and reached down to see that the seal had fallen out of the retainer. And I had no idea that this bearing could spin on the shaft....somehow I missed this Procross topic/issue and I am on HCS and AChat all the time.
 

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Another thing I noticed that has occurred recently, Cat has consolidated the 4stroke 9000 & 7000 driveshaft including drive wheels part number from several into 0728-236 that supercedes many. And the price has gone up.
 

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Every sled I have ever owned needed drive line bearings between 6 and 7000 miles. They aren’t hard to do on a 2 stroke. It is the 3 bolts on the caliper, a clip and a nut inside the chain case to get the shaft out
 
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