Final Drive Surgery with Pics

Are ya having a problem with your rig? We'll try to help. Share your tech tips and experiences here. Dr. Billy Glaser, author of the "Unofficial 750 Ural Service Manual" site myural.com, is moderating this section.
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Here is the place for you to ask questions about or share your experiences about servicing or repairing your Ural or Dnepr. Please post topics concering modifications or accesories in the "Modifications and Acessories" section. Please post oil related questions in the "Oil Threads" section.
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URAL CT
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Re: Final Drive Surgery with Pics

Post by URAL CT » Mon Sep 16, 2013 12:46 pm

One more question...what are the dims on the 3204 A bearing??? Thanks
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Re: Final Drive Surgery with Pics

Post by berger » Mon Sep 16, 2013 12:58 pm

URAL CT wrote:One more question...what are the dims on the 3204 A bearing??? Thanks

http://www.skf.com/group/products/beari ... rial=false

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Re: Final Drive Surgery with Pics

Post by dneprlover » Mon Sep 16, 2013 1:01 pm

20mm id x 47mm od x20.5mm thick
Neval BMW/MT11 800cc hybrid, Neval 2wd MT10-36, Neval standard MT10-36, Neval MT16, another MT11, BMW/MB650 hybrid , K750m , MB750 and a standard MT10-36 outfit + 2 large sheds full of spares for them.

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Re: Final Drive Surgery with Pics

Post by URAL CT » Mon Sep 16, 2013 1:52 pm

Got it. Thanks for the info...Derek & Dneperlover ! :cheers:
Oops... :oops: :oops: I forgot, what is the needle bearing part number? IMZ has 72-052-1 which I can't seem to cross reference to a "standard" bearing part number. Thanks
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Re: Final Drive Surgery with Pics

Post by BinDerSmokDat » Tue Sep 17, 2013 9:22 am

UPDATE: I got all my parts and started putting things together last night. As I noted earlier these bearings are C3 which is the same as the fig's that were in there. Also note these are ABEC 1.

C3 means that internal clearances are slightly larger than CN which is "normal and falls between C2 and C3.
That makes these bearings suitable for very low torque, high loads, heavy interference fits, high temperature and preloading.
Keep in mind there are C1, CN, C2, C3, C4 and C5. These bearings therefore fall in the middle of the common clearances.
So when talking about temperatures and torque, keep in mind we're talking relative terms.
These new bearings are steel cages.

The 3204 bearing spins in conjunction with the wheel, so only about 850 times per mile or at top speed of 65mph, 926rpm.
(Remember this is wheel revolutions per minute, NOT engine rpm) 926rpm is pretty low for a bearing and well within the 14,000rpm limits of the bearing.

The 3304 spins with the pinion so to get 926 wheel rpm it has to turn 4278 pinion rpm (926 x 4.62 gear ratio).
That's still well below the 14,000rpm rating.

As for loading, well the bearings are rated for 2700 pounds Static Load Capacity, 4500 pounds Dynamic Load Capacity.
What does THAT mean? Dang if I know, but I'm pretty sure a Ural doesn't weight 2700 pounds standing still, let alone just exerting that much force on that bearing.
And it certainly doesn't double that force when at top speed.

ABEC 1 means that the bearings have wider tolerances. For example eccentricity (roundness) on an ABEC 9 bearing is 6 times tighter than an ABEC 1 bearing.
But since we're talking about a Ural, the difference between 0.0012mm and 0.0075mm is not going to be a factor. If you are running a jet engine, maybe.


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So here is the 5204 and it goes in the splined hub like so...

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Then give it a tap with a big socket like on Billy G's page or in my case, an experimental exhaust adapter. Just make sure that what ever you use, it is contacting the outer race only! There is a lip it seats on, so note that lip before you insert the bearing and start driving. The bearing sits recessed in the spline hub.


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Re: Final Drive Surgery with Pics

Post by BinDerSmokDat » Tue Sep 17, 2013 9:35 am

Next take the housing like so and place the spline hub inside it. Yes, I greased that bearing, I had w@$#ed it with solvent and wanted to protect it from flash rust.

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Tap the INNER race of the bearing to seat it on the splined hub. It's a loose interference fit so it doesn't take much.

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Drop on the snap ring and install in the groove to keep the splined hub joined to the bearing.

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Then take the 2WD hub and slip it on the arm...note the extra "tab" on the arm. This engages the 2WD ball detent. Make sure this part of the arm is towards the ball detent.

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Drop the 2WD hub onto the splined hub....

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Not a great pic here and a huge error on my part. I outsmarted myself and liberally applied synthetic grease to the 2WD bushing hole and the socket end of the 2wd spindle slips into.
This prevented proper engagement of the end of the spindle into the socket, the grease wouldn't squish out of the hole. So DON'T do what I did. I got a little grease happy after greasing the bearing. ;)
Clean off all the grease and then insert the spindle....

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Then insert the cotter pin...

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Re: Final Drive Surgery with Pics

Post by BinDerSmokDat » Tue Sep 17, 2013 9:40 am

I picked up these at Fastenal while I was ordering new bolts. :D A lifetime supply!
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Re: Final Drive Surgery with Pics

Post by BinDerSmokDat » Tue Sep 17, 2013 9:45 am

Drop the ring gear onto the pinion carrier. Make sure it sits flush with the plate and that the bearing is seated so the bolts clear the bearing ever so slightly on the back side.
Apply red high temp LocTite. I used new bolts as a set was like $3. Cheap insurance.

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I didn't have a torque spec so I put the carrier in the vice with some blocks of wood and torqued by sense of touch with a 1/2 drive socket and breaker bar.
See the removal pic and imagine it in reverse, as I forgot to snap a shot of me installing. :)
I worked in star pattern as I torqued, verifying the bolt heads just clear the bearing.

That's about as far as I got last night.
So at this point I have 3 sub-assemblies that need to come together, the FD case half with the 2WD gears, the ring carrier and the brake plate/pinion carrier case half.
I'll get them together and install the FD, fingers crossed. :roll:

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Re: Final Drive Surgery with Pics

Post by Albuquralque » Tue Sep 17, 2013 10:46 am

When I rebuilt my FD, I was told by a dealer that the ring gear bolt torque was 22 - 26 ft lbs. Basicall the process was torque them to 22 ft lbs, and then turn them a little more to align the flat side of the bolt head to be parallel to the large bearing.
"Put a little gravel in your travel"


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Re: Final Drive Surgery with Pics

Post by BinDerSmokDat » Tue Sep 17, 2013 10:54 am

Coluralado wrote:When I rebuilt my FD, I was told by a dealer that the ring gear bolt torque was 22 - 26 ft lbs. Basicall the process was torque them to 22 ft lbs, and then turn them a little more to align the flat side of the bolt head to be parallel to the large bearing.
Now you tell me.
I'll check them tonight, I know I didn't index them like that, but when I checked the removal pic they were all aligned as you stated.

Image

If the bolt head has room to turn with the bearing in place, why would it matter putting the flats toward the bearing?
Maybe a holdover from the clip days?

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Re: Final Drive Surgery with Pics

Post by Albuquralque » Tue Sep 17, 2013 10:56 am

BinDerSmokDat wrote:
Coluralado wrote:When I rebuilt my FD, I was told by a dealer that the ring gear bolt torque was 22 - 26 ft lbs. Basicall the process was torque them to 22 ft lbs, and then turn them a little more to align the flat side of the bolt head to be parallel to the large bearing.
Now you tell me.
I'll check them tonight, I know I didn't index them like that, but when I checked the removal pic they were all aligned as you stated.

Image

If the bolt head has room to turn with the bearing in place, why would it matter putting the flats toward the bearing?
Maybe a holdover from the clip days?

Sorry BDSD......you posted a lot quicker than I could respond. :(
"Put a little gravel in your travel"


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Re: Final Drive Surgery with Pics

Post by Albuquralque » Tue Sep 17, 2013 10:58 am

BinDerSmokDat wrote:
Coluralado wrote: Image

If the bolt head has room to turn with the bearing in place, why would it matter putting the flats toward the bearing?
Maybe a holdover from the clip days?

I beliveve you are correct. It is probably a hold over when the lock tabs were used and they sat on the bearing side of the bolts. As long as you have clearance between the bolt heads and the bearing, it shouldn't matter about lining up the flats.
"Put a little gravel in your travel"


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Re: Final Drive Surgery with Pics

Post by Albuquralque » Tue Sep 17, 2013 10:59 am

It does look real nice though with all those flat sides lined up! :D
"Put a little gravel in your travel"


Previous Urals Owned: 2004 Wolf, 2006 Tourist, 2006 Patrol (TOW), 2006 Patrol (TOM), 2014 Patrol

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Re: Final Drive Surgery with Pics

Post by BinDerSmokDat » Tue Sep 17, 2013 10:59 pm

ReCycled just left...

:party: The FD is assembled and the case bolted back up! :party:

I'm exhausted. I'll get a few new pics up tomorrow.

Big, big thanks to Dave. He was a huge help.
He's still be driving home as I post his, he left looking more than a little tired.

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Re: Final Drive Surgery with Pics

Post by Albuquralque » Tue Sep 17, 2013 11:21 pm

:lurker:
"Put a little gravel in your travel"


Previous Urals Owned: 2004 Wolf, 2006 Tourist, 2006 Patrol (TOW), 2006 Patrol (TOM), 2014 Patrol

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