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Lister HA3 fitted with mechanical Blackstone reversing gearbox.


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We have an old tug for canal restoration with a Lister HA3 none hydraulic reversing gearbox

It has a Blackstone reversing gearbox.

The first problem was it would not drive in reverse. We adjusted the brake band and that was fixed.

Now the gearbox is always driving forward. The clutch is disengaged ie there is a clear gap between the 2 clutch arms and the actuator ring. Even in neutral the prop is in forward.

This means , for some reason the clutch is not disengaging.
I read that this gearbox shares oil with the engine and there is no dipstick in the reversing gearbox.

Ideas of a cause and details on how to get the cluch assembly woul dbe very greatfull received.]

Thanks

Nick

gearbox.jpg

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Is it a cone or multi-plate ahead clutch. I have had cone clutches on much smaller boxes with riveted on friction material refuse to come out of gear when the rivets wore grooves in the female cone.

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Hi Tony. It is a multiplate clutch.

By the way, thanks for the course you used to run in Stafford. My son came in 2008 or 2009 and now has a marine and car mech and elec business in Queensland and was inspired by you.

Regards

Nick

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28 minutes ago, shaktjor said:

Hi Tony. It is a multiplate clutch.

By the way, thanks for the course you used to run in Stafford. My son came in 2008 or 2009 and now has a marine and car mech and elec business in Queensland and was inspired by you.

Regards

Nick

 

Pleased to be of use.

 

General principles, any chance the splines on the plates have jittered steps in the splined shaft so they can't move apart so easily?

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The forward clutch doesn't fail in many way. It could be stuck (in which case the engine stalls when you select reverse), It could have lost all the teeth on the fibre plates (in which case you'd have no forward), it can drag, or it can break and the broken parts wedge the plates in forward

 

Have you got fully engaged forward, or is it just dragging? I suspect drag as you can get reverse.

 

If it is dragging, chances are the fibre plates have distorted. The solution is to replace them

 

Richard

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17 hours ago, Tony Brooks said:

 

Pleased to be of use.

 

General principles, any chance the splines on the plates have jittered steps in the splined shaft so they can't move apart so easily?

Thanks Tony.

1 hour ago, RLWP said:

The forward clutch doesn't fail in many way. It could be stuck (in which case the engine stalls when you select reverse), It could have lost all the teeth on the fibre plates (in which case you'd have no forward), it can drag, or it can break and the broken parts wedge the plates in forward

 

Have you got fully engaged forward, or is it just dragging? I suspect drag as you can get reverse.

 

If it is dragging, chances are the fibre plates have distorted. The solution is to replace them

 

Richard

 

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Hi RLWP

 

It is drag but not a slight 1.

With the gearbox in neutral so the clutch operating arms are fully disengaged we can turn the prop shaft with a pair of stilsons eg 600 mm long but it is hard.

With this much drag it looks like the prop shaft is going at full speed.

We believe the plates are distorted and are working out how to do a clutch replacement without rmovig the reversing and redfuction gearboxes.

Regards

Nick

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3 minutes ago, shaktjor said:

Hi RLWP

 

It is drag but not a slight 1.

With the gearbox in neutral so the clutch operating arms are fully disengaged we can turn the prop shaft with a pair of stilsons eg 600 mm long but it is hard.

With this much drag it looks like the prop shaft is going at full speed.

We believe the plates are distorted and are working out how to do a clutch replacement without rmovig the reversing and redfuction gearboxes.

Regards

Nick

 

Probably a misunderstanding but reverse is done with that brake band, not the reduction box, although the reduction box might reverse the prop rotation form (say) LH to  RH. I think the reduction box will have to come off. Probably easier to take the whole assembly off and split them on the bench.

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Hi Tony. 

I think I wrote it badly. We need to inspct and probaly change the clutch plates. The reversing gearbox has mounts that are effectively the rear engine mounts. The rear of the reversing gearbox has the reduction box bolted to it. The rear bearing of the shaft coming out of the reversing gearbox is in the reduction box. So it's complex to change the clutch plates.

Regards

Nick

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4 minutes ago, shaktjor said:

Hi Tony. 

I think I wrote it badly. We need to inspct and probaly change the clutch plates. The reversing gearbox has mounts that are effectively the rear engine mounts. The rear of the reversing gearbox has the reduction box bolted to it. The rear bearing of the shaft coming out of the reversing gearbox is in the reduction box. So it's complex to change the clutch plates.

Regards

Nick

 

Pretty much the same as a BMC B type - you have my sympathy but the job has to be done.

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32 minutes ago, shaktjor said:

Hi Tony. 

I think I wrote it badly. We need to inspct and probaly change the clutch plates. The reversing gearbox has mounts that are effectively the rear engine mounts. The rear of the reversing gearbox has the reduction box bolted to it. The rear bearing of the shaft coming out of the reversing gearbox is in the reduction box. So it's complex to change the clutch plates.

Regards

Nick

 

The bottom half of the reversing gearbox and the engine mounts don't have to come off,  if you're lucky. You do have to remove the reduction box and split the case of the reversing box to remove the top half. That done the whole gearset moves backwards out of the bush in the centre of the crank and lifts out. (Careful, it's heavy). One caveat, to do this you need to remove the forward selector fork, and to do that you need to disconnect both halves of the shaft with the gear lever on it at the reverse selector lever and withdraw the long half out the side of the box. If there's not enough clearance to do that, they whole job gets more difficult.

 

MP.

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1 hour ago, shaktjor said:

Hi RLWP

 

It is drag but not a slight 1.

With the gearbox in neutral so the clutch operating arms are fully disengaged we can turn the prop shaft with a pair of stilsons eg 600 mm long but it is hard.

With this much drag it looks like the prop shaft is going at full speed.

We believe the plates are distorted and are working out how to do a clutch replacement without rmovig the reversing and redfuction gearboxes.

Regards

Nick

 

You can't!

 

It's propshaft off, reduction box off, gearbox top off, dismantle the cross shaft and pull out the half shafts, Remove the reverse toggle, remove the bolts that hold down the reverse band. Then you can lift out the clutch pack

 

The pack needs a special tool to dismantle it unfortunately

 

I've done two so far this year

 

Richard

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