Super Major Crown Wheel Bolts Loose/Sheared

[Timeee]

I have just removed the hydraulic unit from my recently acquired 1961 Super Major to investigate why it will not lift in Position Control. The ancient oil took ages to drain out through the clogged gauze basket filter in the base of the unit, so I started to clean out the years of muck and crud that is sitting in the bottom of the rear axle casing. I was surprised to find the sheared off heads of 3 bolts in the crud and then noticed that the crown wheel was only held to its differential carrier by 3 bolts, rather than 12. I was able to remove the sheared off ends of the 9 bolts (luckily), with a lot of time and effort using a pin punch and small hammer.
I just wondered if anyone else has experienced this problem, as the previous design was to have the crown wheel secured to its carrier by 12 big rivets. The transmission sounded "normal" on the 5 miles I have driven the tractor and there appears to be no major damage to the gears in the unit, as the bolt heads passed to the bottom of the rear axle some time in the past, so I could be lucky this time. I think I shall drill the heads of the replacement bolts and lockwire them, as well as using Loctite on the threads.

Tim

[Emiel]

Hello Tim,

Never heard or seen that problem, don't know whether its common or not.

Use high tensile bolts and use loctite. Don't think lockwire will prevent shearing off. Give it a go, there's not too much to go wrong.

These bolt head may have been in there for a very long time.

Good luck

Rgds Emiel

[Brian]

Bolt head and rivet shear was not a common problem but not unknown back in the day. Usually caused by waiting till the wheels were going round like mad and then standing on the dif lock pedal. Same usage that caused teeth to wear on the bull pinions and the bull gears. You will need to get hold of the proper bolts with a shoulder on and make sure they are a good fit in the holes before tightening them up.

Even when running the tractor on steel wheels it was not a common problem.

[AdrianNPMajor]

Hello Tim
Any chance of some photos of your new acquisition and the works you are carrying out? Or, in other words .......

Sorry, I love that emoticon!
Best, Adrian.

[AdrianNPMajor]

Hello Tim
Any chance of some photos of your new acquisition and the works you are carrying out? Or, in other words .......

Sorry, I love that emoticon!
Best, Adrian.