Hetzer sprockets / locking bush issue

[Daniel Scholefield]

I had a feeling this was going to be an issue when the instructions glossed over this and it's happened twice now, as soon as I put load onto the tracks the locking bushes stop locking and the drive axle spins freely. I know what the issue is: the bushes are not on to the required torque, the problem is, to get them to that the inner face of the sprocket is too close to the hull making the track jump.

If I get the spacing right the bush doesn't get tight enough and slips

My question is, how do you fit the damn locking bushes so you have enough purchase to tighten them up sufficiently at the same time not ending up with the sprocket too close to the hull? I can only seem to acheive one or the other...

[Peter Quambusch]

Hi Daniel,

Have you tried inserting the taper lock into the sprocket and then sliding the assembly onto the axle?
If needed use a rubber hammer to push it down, till the sprocket is in line with the tracks.

Regards
Peter

[Daniel Scholefield]

Peter,

Yes that's what I did after I got the first occurance of this and realised the buches were way too loose. This appeared to work when I did my first tests with the tracks on as everything appeared tight and the tracks were aligned. However my first hard turn from speed made them both come loose. I know the problem - both are under-torqued, what I can't get is how to get them sufficently tight and keep the spacing right.

[Peter Quambusch]

Daniel, What do you use to tighten the lock? I use a standard (ring) wrench and have no issues whatsoever.

[Peter Quambusch]

Also make sure that the axle and the lock are clean and free of oil and grease! I wipe them down with Tetra prior to assembly.

[Daniel Scholefield]

Ok, tracks are off and both sprockets were clearly loose. From what Chris Fry told me the 'pull' is 3-5mm so I have postioned the sprocket further out this time so I don't end up too close to the hull. My question at this point is, is this the corrrect starting postion? Assuming this is I need to find some way to stop the sprocket moving when getting close to the 22mn to torque which I ran into last time.

Hopefully I can sort this issue out, this is try #4

[Jerry Carducci]

Didn't someone in another thread make a sort of block or spacer that is of a thickness required to keep the distance between rear of the sprocket and the lower hull wall. I seem to recall they placedit between sprocket and hull when tightening the taper lock to help maintain the appropriate distance.

I am likely remembering this incorrectly. I remember briefly wrestling with the taper lock/sprocket /hull spacing for both the M3 Lee and Sd.Kfz. 7 but in the end it worked swimmingly. I cleaned all parts in acetone. I also assumed the spacing were more like 'guidelines' to quote a phrase...so I wasn't
worried if I was off a bit and so far I've not thrown any track even in the hardest turns.

Jerry.

[Daniel Scholefield]

The crux of the problem.

So after some fiddling about I have both sprockets on with a gap within the published tolerances. The locking bushes are both one and tightened up but not to the 20mn mentioned in the instructions. The problem is now that I can't get them any tighter as there is not enough resistance to allow any further torque. Any suggestions on how to secure the sprockets so I can tighten up the bushs to the correct torque?

[Derek Attree]

Hi Daniel
Can't you fit the tracks to lock the sprocket and then finish tighten the Bush.
Jerry the hetzer bush is a totaly different design with no key way
And very much smaller than the original design ones we are all used to.

Regards Derek

[Daniel Scholefield]

I loath the locking bush now. I had both sides finally aligned and done up to the correct torque, tests in the shed showed no track slippage and everything working with the Hetzer apinning around freely. Took it out into the garden for some runs and after a promising start the same failure occured after two turns, the bush on one side came loose and to add insult to injury the whole bush fell off as I was nursing the Hetzer back to the shed and is current missing somewhere in the grass....

Some improvement in that the left side appears fine but I have no confidence in it holding on now.

[Jerry Carducci]

Hi Daniel
Can't you fit the tracks to lock the sprocket and then finish tighten the Bush.
Jerry the hetzer bush is a totaly different design with no key way
And very much smaller than the original design ones we are all used to.

Regards Derek

I see. I have the Hetzer kit myself however I've not yet gotten into it. Could this be an issue of the output shaft or
bushing itself being out of spec? I realize this sounds like a foolish question but if Daniel is following the instructions
to the letter then some fault must be in the components. If the correct procedure is followed as well as recommended
best practices Occam's razor would indicate the fault lies with the components somewhere.

Sorry but there it is.

Jerry

[Daniel Scholefield]

Update, I found the missing bush parts in the grass and have re-mounted the sprocket and torqued it to 20nm using the tracks to give it enough resistance. I will do another test later this afternoon. I need to be sure that it's not something I am doing wrong which is entirely possible but I am not a fan of the bushes thus far.

[Armortek]

Will bring a spare to Tankfest Daniel.
One of the guys here said he thinks you may have cross threaded the taperlock - but it is pretty hard to tell from the photo.

Kian

[Daniel Scholefield]

Thanks Kian,

I wouldn't put is past me that I have damaged the threads in my efforts. It's just frustrating that the previous lack of grip was entirely down to me not tightening enough, now having fixed that iasue it's still doing it...

[Daniel Scholefield]

Well, the Tankfest dream is over for the Hetzer, once again it happily turns and spins while in the shed, within one turn on the grass outside the righthand bush was loose, it just does not grip. I will take it off tomorrow so I can bring it along with me but I am greatly disappointed...

EDIT after playing with it all morning the issue is still there but I know how to 'quick fix' it enough to get it moving again. As such I am going to bring the Hetzer anyway so those who know more than me (basicly everyone) can take a look and I could swap the bush out then and there.