I recently have had work done on my landrover 300tdi 110 and it involved the removal of the rear propshaft. When I crawled under there yesterday to have a quick look at a few things I noticed that one of the bolts from the prop to the transmission brake drum was missing.

My first instinct is just to find a nut, whack it on, jobs done. Tea and medals. However is this the right thing to do? Would the missing nut (bolt still in place) have caused excessive stress on the other bolts and so they could all be considered 'failed' and so need replacing?

Either way, what bolts would I need, looking online there seems to be various ones of various lengths?

19_Hue_95 said:

I recently have had work done on my landrover 300tdi 110 and it involved the removal of the rear propshaft. When I crawled under there yesterday to have a quick look at a few things I noticed that one of the bolts from the prop to the transmission brake drum was missing.

My first instinct is just to find a nut, whack it on, jobs done. Tea and medals. However is this the right thing to do? Would the missing nut (bolt still in place) have caused excessive stress on the other bolts and so they could all be considered 'failed' and so need replacing?

Either way, what bolts would I need, looking online there seems to be various ones of various lengths?

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Not really, just get a nut on it. Lousy garage obviously lost it and didn't give a damn - I would pull them up on it. It's frankly unacceptable actually. They thought they would get away with it because it was hidden!

The bolts are not in shear (unless they are loose!) they are in tension and clamp the prop flange to the diff/gearbox flange so the 3 in place, where are presumably tight, will have done their job fine, which is to clamp 2 faces together, and they will not have encountered additional "stress". Only if you were to try and drive it seriously hard with a massive load in a trailer up a hill gunning it for example, then maybe you would have had an issue.

3/8" UNF - 9/16" Spanner.

discomania said:

Not really, just get a nut on it. Lousy garage obviously lost it and didn't give a damn - I would pull them up on it. It's frankly unacceptable actually. They thought they would get away with it because it was hidden!

The bolts are not in shear (unless they are loose!) they are in tension and clamp the prop flange to the diff/gearbox flange so the 3 in place, where are presumably tight, will have done their job fine, which is to clamp 2 faces together, and they will not have encountered additional "stress". Only if you were to try and drive it seriously hard with a massive load in a trailer up a hill gunning it for example, then maybe you would have had an issue.

3/8" UNF - 9/16" Spanner.

Click to expand...

Cheers, Ill do that now, good to know about the stresses. the more I think about it the more sense it makes but its good to have a second opinion.
To be fair to the guys that did the work, I am giving them the benefit of the doubt as they have done a excellent job on everything and I think it was an honest mistake.

prop bolts are in shear thats why they are special shouldered bolt but if 3 were tight there would be no issue ,new bolts are frc3602 and nuts nz606041l, as ther are 3/8 unf thread damage is a common issue

This is interesting discussion point. I cannot 100% disagree with you James, and I respect your knowledge and experience but bear in mind the mechanics of the fastener.

As you say they do use the shouldered bolt as you never want a threaded section of bolt to be in shear, but if they are done up properly and tightened down then it is the compressive force - similar to the way a clutch works - that holds the flanges together tight and thus drive is transferred from face to face. If the bolts are loose then the bolts can end up working in total shear therefore the bolt is chosen for best results during failure or inadequate torquing etc.

The elasticity of the bolt provides the clamping force and if you have ever tried to separate 2 items merely clamped together with a little G clamp or similar you will know that your efforts are futile. So these bolts ought only to act in tension more or less all the time they are installed unless something goes wrong.