3G gear box dismantling proceedure

[Jumbosailor]

We collected a mooring line (which stopped the engine) earlier this year and since then it has been difficult to select forward, although once in it is fine.

 

With the manual I started dismantling the gear box to examine all the bits -

Remove cover,

Remove gear lever

Remove upper gearbox housing

remove brake band lever

remove fork cross shaft

remove brake band roller, slding sleeve fork leaver and die and fork lever ross shaft collar

REMOVE REDUCTION GEAR

And this is where I am stuck

 

The upper gearbox cover was very difficult to remove as it forms the upper housing for the rear bearing and was clamped between the reduction gear housing and the two flanges that form the inner bearing housing.

 

Anyway all six bolts holding the reduction box to the 3G are now out and I thought that a gentle lever would move the box aft

but it wont budge off the drive shaft spline.

 

anyone got any ideas? I am reluctant to use the bigger hammer yet!!

 

My ultimate aim is to replace the clutch plates so I dont have far to go - just need to get this reduction box off.

 

I would really love to find an Engineer who would be interested in an all expenses paid weekend in France as I may be getting a little out of m,y depth here - French Engineers from Lister France just say get a new engine and I get no answer from Lister UK - presumably they are of the same opinion.

 

In anticipation

Regards

Paul

 

[frangar]

So have you got the top of the reversing box off?

 

Can you see the rubber o ring round the groove on the reversing box?

 

You might need a large crow bar to slide the reduction box off the shaft if it's been there a while...I did the first time I removed mine...a scary amount of force as I recall.

 

If you can post some pictures we can help as to what you might need to do.

 

Just wondering if you have replacement clutch plates? They aren't always easily available. Also what makes you think this is the problem? Is the drive slipping in ahead or is it just hard to get in gear?

 

Cheers

Gareth

[Timleech]

It's a while since I've done this, but I think you'll need to take the back plate off the reducing gear, complete with output shaft and wheel, and then pull the pinion off the main shaft. That will, IIRC, expose three screws securing the bearing/seal housing to the lower gear case.

 

Tim

 

Edit - yes, as above, you should be able to pull off the reducing gear case without pulling the pinion off the shaft.

Edited November 9, 2014 by Timleech

[frangar]

It's a while since I've done this, but I think you'll need to take the back plate off the reducing gear, complete with output shaft and wheel, and then pull the pinion off the main shaft. That will, IIRC, expose three screws securing the bearing/seal housing to the lower gear case.

 

Tim

 

Edit - yes, as above, you should be able to pull off the reducing gear case without pulling the pinion off the shaft.

Just about to say I don't think you do when you put the edit up!

 

Cheers.

 

Gareth

[MoominPapa]

I would really love to find an Engineer who would be interested in an all expenses paid weekend in France as I may be getting a little out of m,y depth here - French Engineers from Lister France just say get a new engine and I get no answer from Lister UK - presumably they are of the same opinion.

 

Talk to Richard (RWLP) of this parish. He could certainly do the job, and may be persuadable to leave Albion's gilded shores.

 

MP.

[Timleech]

Just about to say I don't think you do when you put the edit up!

 

Cheers.

 

Gareth

 

 

Yes, and it can take a fair bit of judicious force, the case is a close fit on the bearing/seal housing and is quite likely to have been put on with some sort of sealant on the register/ O-ring which has long since gone hard!

It may be worth removing the back plate assembly so that you're only dealing with the relatively light casing, and the meshing gears are removed from the constraints.

 

Tim

[frangar]

 

 

Yes, and it can take a fair bit of judicious force, the case is a close fit on the bearing/seal housing and is quite likely to have been put on with some sort of sealant on the register/ O-ring which has long since gone hard!

It may be worth removing the back plate assembly so that you're only dealing with the relatively light casing, and the meshing gears are removed from the constraints.

 

Tim

When I tried that I couldn't shift the nut that holds the small gear on the shaft for love nor money…in fact I did damage the threads on the shaft which thankfully Llewelins were able to sort when the whole lot landed in their workshop (I did take the split pin out btw!).

 

I ended up taking the gear cluster out with the reduction box still on and working on it on the bench…its not a light lift out the engine room…..

 

Gentle but firm force was needed…and patience to make sure it was coming apart square.

 

When I put it back together I didn't use any sealant apart from some grease. I did make a new o ring though.

 

Cheers

 

Gareth

[Jumbosailor]

So have you got the top of the reversing box off?

 

Can you see the rubber o ring round the groove on the reversing box?

 

You might need a large crow bar to slide the reduction box off the shaft if it's been there a while...I did the first time I removed mine...a scary amount of force as I recall.

 

If you can post some pictures we can help as to what you might need to do.

 

Just wondering if you have replacement clutch plates? They aren't always easily available. Also what makes you think this is the problem? Is the drive slipping in ahead or is it just hard to get in gear?

 

Cheers

Gareth

Yes I have the clutch plates - I brought them last year thinking that it might have been the problem I was having with difficulty finding neutral, but never got the nerve to open the beast and replace them - now we are in our winter mooring I have six months to get it right or shout mayday - Yes I can see the O ring now, I probably need to replace that when I re-assemble me thinks!!

I have shelved the dismantling for a week as I have to visit my Ailing mother in the UK.

For you and others on the Forum, I am using A E Woodward for spare parts they never cease to amaze me with what they can find in their workshop

Regards

Paul.

[Jumbosailor]

Does any one have Richard's phone number - I have sent him an email from the Primose Engineering Wbesite but

as yet no reply - I also tried phoning him and got no reply - does he have a mobile where I could get him?

[RLWP]

Apologies, I'll email you today

 

Richard