Lister LH150 Reversing Box

[springy]

I think the end float is less of a problem, and may actually be necessary - to "engage"

neutral requires item E to move backwards away from item D although E should just

slide on the splines. As Tim said when you refit the reduction gears (or fitted an output

housing for a 1:1) this may well eliminate the end float.

 

springy

[paulcatchpole]

I think the end float is less of a problem, and may actually be necessary - to "engage"

neutral requires item E to move backwards away from item D although E should just

slide on the splines. As Tim said when you refit the reduction gears (or fitted an output

housing for a 1:1) this may well eliminate the end float.

 

springy

 

They had a half-coupling fixed to the main shaft, in muh the same way the the reduction pinion is. Without that, the shaft can move forwards until it meets something else inside the box.

 

Tim

 

Ahha, great stuff both of you - that's good news. I'll forget about it for the moment then.

 

I think we're back to me giving it a good coat of looking at and a poke to see if it'll free up. I'll check the adjustment while I'm at it too...

 

Cheers!

[WotEver]

From watching the video

 

 

Richard

D'oh! I'd completelty missed that the bit that Paul was waggling was part E.

 

Tony

 

edit to say that according to post #71 they may still be stuck together? I'm confused now.

Edited May 5, 2010 by WotEver

[paulcatchpole]

D'oh! I'd completelty missed that the bit that Paul was waggling was part E.

 

Tony

 

edit to say that according to post #71 they may still be stuck together? I'm confused now.

 

I guess if when I'm waggling that abut, that E and D are locked together but are moving on either their own splines in the centre, or the whole lot is moving on a knackered drive plate, or lash in some other part of the sytem, input sun gears maybe?

 

Not long till I'm back there and can give it a good poke to see what's going on - I didn't want to poke too hard last time, but now I think I understand it a bit better, there'll be no stopping me!

 

PC

[Timleech]

I guess if when I'm waggling that abut, that E and D are locked together but are moving on either their own splines in the centre, or the whole lot is moving on a knackered drive plate, or lash in some other part of the sytem, input sun gears maybe?

 

Not long till I'm back there and can give it a good poke to see what's going on - I didn't want to poke too hard last time, but now I think I understand it a bit better, there'll be no stopping me!

 

PC

 

I'd still try putting something back to hold the mainshaft back - just a bit of tube and the nut would do it - before digging too deep. Not sure it'll help, but it would eliminate one aspect.

 

Tim

[paulcatchpole]

I'd still try putting something back to hold the mainshaft back - just a bit of tube and the nut would do it - before digging too deep. Not sure it'll help, but it would eliminate one aspect.

 

Tim

 

No problem, the bits to reassemble the reduction should all be here by the weekend, so I can stick it back together and back on the end - it's not a great pain to have to remove it again if needed.

 

Interestingly, the nut on the end of the output shaft from the reverse box, which retains the inner bearing race and input gear (to the reduction), was loose - as in no spanner required - although in place due to its split pin. Interesting I thought...

 

PC

[MoominPapa]

Interestingly, the nut on the end of the output shaft from the reverse box, which retains the inner bearing race and input gear (to the reduction), was loose - as in no spanner required - although in place due to its split pin. Interesting I thought...

 

Consider how the spring-pack tension is retained. At the right hand side the spring buts against the inner race of the bearing and the force rightwards is ultimately countered by tension in the shaft. The left hand side of the springs pushes the cone which pushes the spider which pushes against the right side of the output gear via thrust washer that returns the force to the output shaft and balances the tension.

 

I'm not, therefore, surprised that the nut was loose(ish), the tension in the shaft is the spring pressure, it's not done up "solid" against steel components.

 

I think the other lesson of this insight is what Tim has been saying - you can't expect is to work at all unless you have a bearing, gear and nut on the end of that shaft - the spring system relies on them.

 

MP.

[paulcatchpole]

Consider how the spring-pack tension is retained. At the right hand side the spring buts against the inner race of the bearing and the force rightwards is ultimately countered by tension in the shaft. The left hand side of the springs pushes the cone which pushes the spider which pushes against the right side of the output gear via thrust washer that returns the force to the output shaft and balances the tension.

 

I'm not, therefore, surprised that the nut was loose(ish), the tension in the shaft is the spring pressure, it's not done up "solid" against steel components.

 

I think the other lesson of this insight is what Tim has been saying - you can't expect is to work at all unless you have a bearing, gear and nut on the end of that shaft - the spring system relies on them.

 

MP.

 

I'm not sure I understand the intiial explanation there, but then I'm not having a very sharp day!

 

With the lever next to letter G pushed over to the left, compressing the spring pack (against the casing, effectively) at the other end of the lever, there's no tension in the cones and shaft, is there? So it should rotate freely in a complete revolution, in a true neutral sense?

 

PC

[MoominPapa]

Looking again, I may be wrong: It looks like there's a bush underneath the spring pack which spans the gap between the spring backplate and the end of the splines. If that's the case then the nut should do up tight, but running without anything on the end of the shaft is still going to mess up the operation of the box.

 

Fun this, isn't it?

 

MP.

[paulcatchpole]

Looking again, I may be wrong: It looks like there's a bush underneath the spring pack which spans the gap between the spring backplate and the end of the splines. If that's the case then the nut should do up tight, but running without anything on the end of the shaft is still going to mess up the operation of the box.

 

Fun this, isn't it?

 

MP.

 

Lots of fun! Better than w*rk anyway...

 

Gives me lots of ideas to work with when I'm back there at the weekend. Will have laptop this time to be able to report progress back!

 

PC

[MoominPapa]

With the lever next to letter G pushed over to the left, compressing the spring pack (against the casing, effectively) at the other end of the lever, there's no tension in the cones and shaft, is there? So it should rotate freely in a complete revolution, in a true neutral sense?

 

Yes, probably, but when that lever _isn't_ compressing the spring pack, the springs are pushing the cone and spider leftwards. I think what stops them being pushed into the casing is a thrust washer between the LHS of the output gear and the spider. If there's nothing stopping the output shaft moving left, because the nut is missing, I can't see anything else that stops the whole spider assembly and the shaft from moving left and grinding against the case. I wonder if that's the source of your nasty noises?

 

 

MP.

Edited May 5, 2010 by MoominPapa

[paulcatchpole]

Yes, probably, but when that lever _isn't_ compressing the spring pack, the springs are pushing the cone and spider leftwards. I think what stops them being pushed into the casing is a thrust washer between the LHS of the output gear and the spider. If there's nothing stopping the output shaft moving left, because the nut is missing, I can't see anything else that stops the whole spider assembly and the shaft from moving left and grinding against the case. I wonder if that's the source of your nasty noises?

 

 

MP.

 

Ah, yes I now see what you mean... Could be possible, in terms of the movement, aye...

 

The noises however, fortunately, weren't coming from the gearbox. With the second engine start, and an exhaust, I could get close enough to the casing to hear that it was coming from the pulley end of the engine. No idea what it was but it went away after about a minute and hasn't returned yet. No nasty noises from the gearbox, the main symptom being it stalling when put into reverse...

 

PC

[paulcatchpole]

Morn' all.

 

Following a visit to the local public house last eve with my best friend, who's rather a better engineer than me (did a course and everyfink)...

 

What about arranging some load on the output of the reverse box (or reduction if it's back on)?

 

Perhaps even ensuring the engine won't start, lock the output and turn the engine over on the starter, well *try* and turn it over? Might just unstick the stuck bits.

 

This'd be with the bolt screwed in for manual release, in the context of trying it on the starter, and without the screw screwed in for the case of applying load once it's running and spinning with neutral selected...

 

PC

[Guest User]

Morn' all.

 

Following a visit to the local public house last eve with my best friend, who's rather a better engineer than me (did a course and everyfink)...

 

What about arranging some load on the output of the reverse box (or reduction if it's back on)?

 

Perhaps even ensuring the engine won't start, lock the output and turn the engine over on the starter, well *try* and turn it over? Might just unstick the stuck bits.

 

This'd be with the bolt screwed in for manual release, in the context of trying it on the starter, and without the screw screwed in for the case of applying load once it's running and spinning with neutral selected...

 

PC

 

Being the optimistic sort, I'd like to think it will run free (when manually disengaged) with the reduction box back on. The manual clutch release is, in part, to enable the reduction output flange to be rotated to align with a coupling. IMHO I'd re-fit the reduction box and then check by hand to see if everything's still jammed up. If no joy then think about getting some resistance on the output but I'd be wary about locking it up solid and then running the engine ... visions of metal bits getting stripped and graunched ... but then maybe the threat of a big hammer and some impact technology might coax it into freeing up.

Edited May 6, 2010 by Graham!

[paulcatchpole]

Being the optimistic sort, I'd like to think it will run free (when manually disengaged) with the reduction box back on. The manual clutch release is, in part, to enable the reduction output flange to be rotated to align with a coupling. IMHO I'd re-fit the reduction box and then check by hand to see if everything's still jammed up. If no joy then think about getting some resistance on the output but I'd be wary about locking it up solid and then running the engine ... visions of metal bits getting stripped and graunched ... but then maybe the threat of a big hammer and some impact technology might coax it into freeing up.

 

Aye, I don't want to run the engine with it locked up, but I thought some persuasion from the +2kw starter might encourage it - with the engine engineered not to start of course...

 

Well, it's certainly the easiest first option, to put the reduction back together and see what happens, so I'll do that!

 

PC

 

PS: Isn't graunch such a descriptive and slightly chilling word?

[MoominPapa]

Perhaps even ensuring the engine won't start, lock the output and turn the engine over on the starter, well *try* and turn it over? Might just unstick the stuck bits.

 

This'd be with the bolt screwed in for manual release, in the context of trying it on the starter, and without the screw screwed in for the case of applying load once it's running and spinning with neutral selected...

I think if it were me, I'd want to known exactly which bits were jammed before I attempted this. Was that ever determined? Oh and I'd definitely put the reduction box back first.

 

MP.

[paulcatchpole]

I think if it were me, I'd want to known exactly which bits were jammed before I attempted this. Was that ever determined? Oh and I'd definitely put the reduction box back first.

 

MP.

 

Dunno, how am I to determine it?

 

PC

[MoominPapa]

Dunno, how am I to determine it?

Dunno, but answer me this, which I can't determine because the x-section we have is for a 1:1 box without a reduction box.

 

What is currently supporting the output shaft? Is the bearing shown in the 1:1 diagram there, or is that missing with its function taken over by one of the reduction-box bearings?

 

It occurs to me that if the missing reduction box means the output shaft can move leftwards as well as rightwards then pulling the cone leftwards will just move both halves of the forward clutch and not disengage it at all.

 

MP.

[paulcatchpole]

Dunno, but answer me this, which I can't determine because the x-section we have is for a 1:1 box without a reduction box.

 

What is currently supporting the output shaft? Is the bearing shown in the 1:1 diagram there, or is that missing with its function taken over by one of the reduction-box bearings?

 

It occurs to me that if the missing reduction box means the output shaft can move leftwards as well as rightwards then pulling the cone leftwards will just move both halves of the forward clutch and not disengage it at all.

 

MP.

 

 

I'd say from the diagram that the output shafe had two bearings, the outer one, in a lovely mauve colour here, being a split race thrust bearing - for when this is designed to run without the reduction?

 

 

Does that look right to you?

 

PC

[MoominPapa]

I'd say from the diagram that the output shafe had two bearings, the outer one, in a lovely mauve colour here, being a split race thrust bearing - for when this is designed to run without the reduction?

 

 

The red bearing is the clutch release bearing. It doesn't support the shaft but transmits rightwards "pull" from the lever to the rotating parts of the clutch. The hydraulic cylinder pushes left, the lever pivots on the fulcrum and the other end, which I assume is forked like a car clutch release bearing, pulls the bearing right, counteracting the force from the spring, allowing the cone to move right and disengaging forward drive.

 

MP.

[WotEver]

The red bearing is the clutch release bearing. It doesn't support the shaft but transmits rightwards "pull" from the lever to the rotating parts of the clutch. The hydraulic cylinder pushes left, the lever pivots on the fulcrum and the other end, which I assume is forked like a car clutch release bearing, pulls the bearing right, counteracting the force from the spring, allowing the cone to move right and disengaging forward drive.

 

MP.

In that case, I can't see how having the reduction box attached will help. It's not going to stop any rightwards movement of the shaft, is it?

 

Tony

[paulcatchpole]

The red bearing is the clutch release bearing. It doesn't support the shaft but transmits rightwards "pull" from the lever to the rotating parts of the clutch. The hydraulic cylinder pushes left, the lever pivots on the fulcrum and the other end, which I assume is forked like a car clutch release bearing, pulls the bearing right, counteracting the force from the spring, allowing the cone to move right and disengaging forward drive.

 

MP.

 

Right, I understand that bit now, ta!

 

The mauve ones are supporting the shaft though, all the same - in reference to your question on support?

 

PC

[MoominPapa]

The mauve ones are supporting the shaft though, all the same - in reference to your question on support?

On the G2 box I have, the equivalent of the mauve bearing is not fitted if the reduction box is used - the support comes from the bearings in the reduction box instead. I don't know if the same is true on the LH150, since the only drawing I can see is the one without the reduction box.

 

MP.

 

 

 

 

In that case, I can't see how having the reduction box attached will help. It's not going to stop any rightwards movement of the shaft, is it?

 

Tony

Two different bearings.The release bearing (red) pulls the cone right, but something has to stop the other half of the clutch from following it. From the diagram that something seems to be the output shaft and (mauve) bearing. It's possible that the reduction version of the box, which we don't have drawing of, doesn't have the mauve bearing, it relies instead on the reduction box bearings.

 

MP.

 

Edited 'cause a mixed up my reds and mauves

Edited May 6, 2010 by MoominPapa

[paulcatchpole]

On the G2 box I have, the equivalent of the mauve bearing is not fitted if the reduction box is used - the support comes from the bearings in the reduction box instead. I don't know if the same is true on the LH150, since the only drawing I can see is the one without the reduction box.

 

MP.

 

 

 

 

 

Two different bearings.The release bearing (red) pulls the cone right, but something has to stop the other half of the clutch from following it. From the diagram that something seems to be the output shaft and (mauve) bearing. It's possible that the reduction version of the box, which we don't have drawing of, doesn't have the mauve bearing, it relies instead on the reduction box bearings.

 

MP.

 

Edited 'cause a mixed up my reds and mauves

 

I'm not sure there is a separate version as such - I'm sure I've got one of the lister manuals somewhere which gives instructions on how to add the gearwheel rather than the flange, for fitting the reduction, but I'm pretty sure it doesn't mention bearings...

 

PC

[alan_fincher]

Probably not much help, but I still have the manual for a Parsons box.

 

The way that worked was there was always a bearing present, but it was a "special thrust bearing" if the gear box was configured for direct drive, but a "plain journal bearing" if a reduction box was fitted.

 

The manual spells out, (IN CAPITALS), that it one has to be removed, and the other substituted, if a reduction box is being added or removed.

 

There is incidentally something similar for the output of the reduction box, that also normally had thrust bearings. If your prop-shaft included it's own, then, (IN CAPITALS AGAIN!), you had to modify the bearing in the reduction box to a plain journal one "of similar dimensions".