Instructions for replacing faulty bearing on diamond drive?

Forgive me if I haven't followed all the threads on this, but is the 2010 M8 DD/bearing/or clearance slightly different than other models, thus requiring machining the shaft or some other non-routine adjustment to compensate for different clearances?

Coldfinger said:

Forgive me if I haven't followed all the threads on this, but is the 2010 M8 DD/bearing/or clearance slightly different than other models, thus requiring machining the shaft or some other non-routine adjustment to compensate for different clearances?

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Yeah...I thought there was a problem with using the wider bearing on the newer cases? If I remember right the original skinny bearing lets part of the shaft on the gear stick out and there is a hollow spot on the case it goes into. When using the wider bearing the bearing is flush with the shaft on the gear so hits the case when you put the cover back on. I thought some guys were having problems with this?

1080paul said:

Yeah...I thought there was a problem with using the wider bearing on the newer cases? If I remember right the original skinny bearing lets part of the shaft on the gear stick out and there is a hollow spot on the case it goes into. When using the wider bearing the bearing is flush with the shaft on the gear so hits the case when you put the cover back on. I thought some guys were having problems with this?

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This is correct..........I just did my 2010 M8 and a my buddies 2010 M8 then another friends 2009 M8. On the 2010's the difference between the wide bearing and the stock bearing and spacer is 1.5mm or 0.050" with the wide bearing being that much wider than the stack up of stock spacer and bearing. I had to machine the step on the transfer gear shaft and remove that 1.5mm / 0.050" of difference so that the wide bearing would sit in the same spot / location on the shaft and allow the cases to close together without problem. Now..........1.5mm / 0.050" may not seem like much but it is enough that it WILL cause problems if you try and put the case back together without machining the transfer gear shaft. I am lucky to have access to a full machine shop at work.

Now......on the 09 M8 the difference is much less........the wide bearing was on this particular sled 0.014" inches different than the stock bearing and spacer. 14 thousandths of an inch is very close and a guy might be able to make the case seat together and work......however since I was in the machine shop anyway I just removed that 0.014" off of the transfer gear shaft so that the new wide bearing would be spot on location.

I should note also that on the two 2010 M8's that I did I found the stock bearing and spacer stack up length to be different by 0.003" inches or 3 thousandths of an inch. Not a ton........but still they were not exactly the same so something to be aware of that when numbers are posted here they are what each person found on there sled........your sled may be slightly different. I hope this helps.......there are a couple other threads on here........one that is 9-10 pages long that details this whole situation in incredible detail.

On a last note.......so people don't make the same mistake I made.......the case cover bolts should be torqued to 7.5-to-10 ft. lbs. not the 12 ft.lbs like a lot of folks have been saying. The case cover bolts are M6X1 and the torque spec for that fastener into aluminum is 7.5-to-10 ft.lbs. the torque spec for that fastener when threading into a piece of steel is 12-to-14 ft.lbs. I went by the 12 ft.lbs. number and ended up pulling the threads out of a couple of the holes. This resulted in me pulling the whole DD and heli-coiling the messed up holes........and while I was at it I heli-coiled them all. Not a tough job.........but a pain in the butt when it's not necessary.

On my buddies sleds I used 100 inch pounds for a torque spec which is roughly 8.3 ft.lbs. and the stock aluminum case threads held up well. Just trying to help you guys from doing like I did on my sled. I hope all this helps...........happy sledding!

Dave

if you are on an 09 m8, the wide bearing from BDX fits without machining. That is what I have and that is what I personally did, it fits perfect.

you can get just the bearing from BDX for about $18 plus shipping.

I just talked to BDX last week because I couldn't get a straight answer any where. On a 2010 they recomend to completley pull the DD, and machine .055"-.075 off of the DD end of the track shaft. If you don't do the machining and just take loose the trackshaft bolt your gears will overhang each other and there will be binding in the case.

Final answer!

kraftymike said:

I just talked to BDX last week because I couldn't get a straight answer any where. On a 2010 they recomend to completley pull the DD, and machine .055"-.075 off of the DD end of the track shaft. If you don't do the machining and just take loose the trackshaft bolt your gears will overhang each other and there will be binding in the case.

Final answer!

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To machine the shaft, do the drivers need to be removed?
Anyone know what the typical cost is to machine the shaft?

Is it possible to use a hand grinder to take off .075" as long as it is done
slowly and with plenty of stops to keep the shaft from overheating?

Dogmeat said:

Ok, so the BDX bearing kit for 07+ diamond drives HAS the wide bearing?

This is the kit I ordered:

http://bd-xtreme.com/bdxdiamonddrivebearingkit07-upreverse.aspx

So I'm going to have to have my drive shaft machined to take ~0.015" off in order to get the proper tolerance?

Or, I can go to NAPA and get a 4203 bearing and it will fit no issues?

Will be on an 09'.

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I went to NAPA and got the 4203 bearing it works fine. That is all they have where i live and the guy at NAPA said that it is the same as the 5203

The 4203 and 5203 are not the same. You can go to the SKF bearing web site and get the specs for each.

Seem to remember reading that the 4203 is a straight drop in for the 2010 it is slightly smaller than the 5203,anybody know if this is correct?

todb said:

Seem to remember reading that the 4203 is a straight drop in for the 2010 it is slightly smaller than the 5203,anybody know if this is correct?

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This could be correct for some.........I did the 5203 bearing on 2 different 2010's and the width of the spacer behind the stock bearing was different on both of the sleds by a bit. Enough that when machining the transfer gear to fit the 5203 bearing we had to take off differing amounts of material for each of the two.

Some guys have said that the 4203 was a direct replacement for the stock bearing and spacer.........so just make sure that you measure carefully the stock bearing and spacer on your 2010........and make sure it matches the width of the 4203 bearing. It should be close.

Also.......the difference between these two bearings is that they are both double-row bearings meaning they have two rows of ball bearings inside.........however the 5203 is an "angular contact" bearing and the 4203 is a "straight double-row roller bearing". The 5203 bearing has beveled inner and outer races within it that allow the bearing to take a side load / thrust load on the ends as well as providing load support up and down. I hope that makes sense. The 4203 is a straight roller bearing made to take load up and down but not side-to-side.

There is a 10 page long thread on this subject that goes into great detail......do a search and you will find it. Lots of great information there.
The stock bearing is cheap........but there is a couple different things causing them to go bad. Some of it can be from a thrust load placed on the bearing by the planetary gear set........the other is that on some of the 2010's the tunnel itself was manufactured a bit to narrow on a lot of sleds.

The affect of the tunnel being narrow is that when you go to assemble the diamond drive into the chasis.......the correct length drive shaft pushes the ring-gear/output shaft of the diamond drive too deep into the case. Think of it like this.....you have a drive shaft to length.......and you bolt up the tunnel side of your diamond drive housing to the tunnel.......and to a tunnel that is a bit too narrow. Now you place the ring-gear output shaft ( first piece to go in the diamond drive and attach to the track shaft) well if the tunnel is to narrow and the track shaft and ring-gear output shaft are to their blue-printed nominal length.....well now that ring-gear output shaft is sticking too deep into the diamond drive case. When you put the planetary set in......and then the transfer gear......well that transfer gear bearing now rides in and seats out on the I.D. of the ring-gear output shaft of the diamond drive. When you put the case halves of the diamond drive together on this sled with a tunnel that's too narrow you are now placing one heck of a pre-load on the bearing that rides on the I.D. ( inside diameter ) of that ring-gear output shaft.

This is why the gentleman stated above that the correct way to fix this problem would be to take the track shaft out and trim some off it's length. This would make up for the tunnel being too narrow. The narrow tunnel is why alot of these stock bearings are grenading.............lots of side load. The other way to tackle the problem is to machine the transfer gear for the proper clearence and put the double row angular contact 5203 bearing. Though.......it's not as good a fix as machining the track shaft. Sorry for the novel.......just felt inclined to help. The long thread has much more information and pictures to go along with what I have said here.

Take Care and Happy Sledding!

Dave

Rather than machine down the track shaft, would it be possible to shim the brake Caliper assy by using a few flat washers?? I've never had mine apart but looking at the parts diagram it appears that installing a few flat washers as shims may work??

I just installed th 5203 bearing on my 2010, I left it in the sled and just took the cover off, the cover went back on fine, am I going to have problems if I dont have the shaft or gear machined. I am also getting ready to do my bros 2009, will the 5203 bearing work fine on that one?

how much is everyone grinding of the track shaft? So if I machine .050 off the transfer gear I am good? or min of .050?

I AM IN THE MIDDLE OF DD ISSUES MYSELF - 07 M1000 - ORDERED LOWER RATIO GEARS FROM BDX - TOOK DIAMOND DRIVE OUT AND FOUND PLANETARY GEAR (ONE OF THEM) MISSING A FEW TEETH - THAT IS THE 2ND TIME THAT HAS HAPPENED ON THIS SLED - ORDERED PLANETARY FROM BDX - DECIDED THAT I WOULD REPLACE ALL THE BEARRINGS IN THE DD (TOTAL OF 5) - THE BIG BEARRING ON THE OUTPUT SHAFT HAD SOME AREAS THAT LOOKED LIKE HOT SPOTS - ARCTIC CAT DOSNT SELL THAT BEARRING SEPARATELY (COMES AS WHOLE OUTPUT SHAFT) AND MY LOCAL BEARRING GUY COULDNT GET ONE EITHER - ENDED UP ORDERING THE KIT FROM BDX FOR THAT - THE KIT FROM BDX DOSNT LOOK LIKE IT HAS THE INPUT BEARRING (ONE BEHIND SECONDARY) IN IT THOUGH - ORDERED THAT ONE FROM CAT - WITH ALL THAT BEING SAID - AM I GOING TO HAVE TO MACHINE SOMTHING ON AN 07 W/ THE BDX BEARRING AND GEAR KIT? - I KNOW THE THERE NEW GEAR REQUIRES REMOVAL OF A WASHER BEHIND THE BEARRING AT THE END OF THE GEAR - NO ONE AT BDX SAID ANYTHING ABOUT IT????

Dogmeat said:

Ok, so on a 2009 with the BDX bearing I have to machine the shaft, if I go to NAPA and buy a 4203 bearing I don't.

Guess I'm gonna go for th 4203 because I really don't want to have to machine the track shaft

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The machine work in question is for the 2010's the 2009's do not need any machine work to install the 5203 bearing. Which is the correct bearing. Call BDX and tell them what you are doing and order the bearing from them.

Did mine tonight. 2010 M8 500 miles, bearing totally shot cage in multiple pieces. Way to go A/C:face-icon-small-dis

Used the 4203 fits perfect, why is it that people want to use a different one that requires machining?

Seems like a lot of unecessary work and complication...

Edit: Has someone had a 4203 fail that I don't know about?

correction - bdx bearring kit does have 5 bearrings in it