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Herald half shafts needle bearing surfaces


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Hello, again.

moved onto rear hub rebuilds.

I have the hubs apart and rebuild kits. Only thing niggling me is some slight pitting on the surface of one of the drive shafts where the needle bearing runs.

I took these hubs apart a few years ago all the bearings seemed pretty good to be honest but it seems silly not to replace them now they're apart.

About six months before I pulled the hubs I had put new UJ's in.

So every thing should be spot on other than the slight pitting on one shaft.

Should I not worry too much and just get them back together? I should image most Heralds out there are running around with slightly worn needle bearing surfaces?

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the needles dont carry much load they keep the trunion from wobbling on its single ball race  it may well run for miles kept greased  .

if they destroy then its game over as the back plate/ trunnion etc will not be held perpendicular to the shaft  

lets say its more of a steady than a load carrier , but still important 


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Thanks Pete, I did think that they were not huge load bearers but it's reassuring to hear it from another ( more knowledgeable ) person.

I would think the ball race does 95% of the work, very strange design, I wonder why Triumph did not fit a smaller ball race rather than relying on the shaft as a bearing surface? I would have thought it would need case hardening and grinding in that area too so popping a ball race there would have probably been cheaper...odd?

I suppose our cars are much more cossetted than they were when they were daily slogs, it will be greased on a regular basis and not cover large distances so hopefully it will last a while.


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No worries Pete.

But something else is holding me up.

According to my factory manual the front of the trunnion should sit 2.625 inches from the end of the drive shaft. I have set it to that distance and the other end of the trunnion is nowhere near the flinger and the hub with the wheel studs hits the ball bearing before it locates on the taper??

Very confusing, is the 2.625 dimension correct? or have I unknowingly got weird driveshafts?

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OK Pete, good to see you have had similar issues with those dims.

I'll move it all around until it lines up. What had never occurred to me is the trunnion is not actually solidly located on the shaft, it relies entirely on the friction between the inner ball race and the shaft to keep it in place! The whole rear end design is very odd but it seems to work!

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on my vit 6 we had one shaft with a location register and one plain the silly churchill tool dimensions only poke the bearing hsg on far enough to allow the hub to engage and start a nut but the book does not explain the missing link ,  Im sure when you button the nut up it will be fine

what can goe wrong is if someone whacks it on too far in the first place then you can see the linnings are edged outside the drum 

i have a local spitty like that and theres no simple way to reposition it .apart from grovel and struggle with a deep drag to pull the hsg back .


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I've attached a couple of pics of mine.

If anyone has any shafts around and could measure the distance between either the flange that the drum sits on to the end of the shaft or to the bearing ( see pics ) that would be great.

Factory dims seem way off!!

Drum doesn't catch on the backplate yet but as can be seen in pic there is still a gap at the flinger and where the flange pushes into the seal. 



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I'm with Pete on this, ignore the factory dimension, the flange will drive the trunnion assembly to where it needs to be. A while ago I was talking to a retired mechanic who did his fair share of these. He told me he hated the job (mostly due to the taper fit), but also he struggled to position the housing correctly (he used to mark the shafts before disassembly). He had a eureka moment when I explained doing it the way Pete says.

Picture of one of my old driveshafts (since scrapped), you can see the marks where the bearing has been, looks like your housing definitely needs to go further (which would agree with the gap on the inner flinger). I'm not convinced all the threaded sections are the same length either, I've seen some longer and some shorter. The way you're measuring is going to cause a discrepancy as you're following the taper rather than staying parallel with the shaft.

P.s. the other gotcha with these is the inner seal, these are fitted "backwards" such that grease can escape but water can't get in. Oh and don't forget the outer flinger which keeps grease from the brakes.


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Yes Frog I'm going to rely on the hub pushing the bearing into the correct location, It also sets the outer seal into the correct position on the hub seal surface.

Yes the inner seal, I ummed and ahhhed over fitting it 'backwards' but I figured it was more to allow excess grease out when regreasing and wanting it to squirt out the inner side rather than brakes side. Also as you said it makes an effective water seal that way.

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