D160 carrier bolt failures

[Petes Horse 20]

Hello,

 I'm trying to stop my D160 from shearing the bolts in the rear again and have some questions about the failures.

Do the bolts just get loose enough to allow the head to be sheared off by the case?

Does the threaded end fail/snap allowing the bolt to slide out shearing off the head?

Anyone upgrade their bolts and have them break again?

Were the other bolts loose as well?

I'm hoping it's due to improper torque and not from the bolts limited clamping force.

I know I'm thinking way too deep into this but that's part of the fun.

 

Thanks

 

[R. L. Addison 299]

What size are the bolts? The "C" & "D" series were the same size originally, as I have had to drill to 3/8 " from 5/16". (Best I remember anyway the first was my "C" and the second was a "D") I think it was service bulletin prompted, correct me if I'm wrong.  The next thing is grade 8 bolts & nuts. The next thing I did was remove the calcium chloride from  my rear wheels and use just the weights for ballast. 

 

When a person is driving these tractors if the direction control is "slammed" into opposite direction, the hubs & bull gear act like a shear cutting steel on both sides of the bull gear. If the holes are over-sized at all, it is just like trying to cut a bolt with a cold chisel & hammer. Eliminate all loose motion in these bolts or you will never hold those bolts, especially with a loader.

I have had very little drive-train problem since.

[pacer 3,174]

The bolts should be grade 8, or better yet grade 9, with locking nuts. Many of the D's got out with grade 5's in them and they just didnt hold up....I blew the whole bottom of the cases out on my D-180 when one of them failed!

[Petes Horse 20]

The bolts are 5/16 and are already grade 8. I think the guy that fixed the previous damage used better bolts.

[Petes Horse 20]

An 8 speed read just popped up on ebay. If it has 1-1/8 axles would it work in the d160? This would be the best solution.

[pacer 3,174]

It might bolt up -------------- BUT, where you gonna put the shifter/s, and then theres a slight problem with a clutch mechanism?

[Petes Horse 20]

I was just thinking about changing the differential to get the larger bolts. If they are the larger bolts.

[pfrederi 17,887]

Changing the differential would work but you would have to reuse your axles.  You should get GR9 bolts and Locking nuts.

[Petes Horse 20]

Will definitely go grade 9 and thankfully the axles and everything else inside the trans is in very good shape.

Does this look like the right diff?

Edited October 20, 2017 by Petes Horse

[pfrederi 17,887]

If it 1-1/8" axles and  8 pinions your are set.  The hardened washers mentioned in the TSB are still available.  However i would think any GR 8 or 9 washer that would fit in the machined surface would suffice.

 

[Petes Horse 20]

Thanks for the help. Just got into Wheel horses and there is a lot to learn. Almost as addictive as old VWs.