Info on pre-war half-shaft replacement.

[Tony Fearn]

I've got a rather ominous knocking on 'Mary Ellen's' off-side rear hub.

I'm going to remove the back axle, and if necessary replace the half-shaft and the wheel bearing.

Can anyone direct me to a 'workshop manual' type of publication, perhaps in the archives, that will spell it out how to do in easy stages?

Tony.

P.S. Look in the Australia/NZ section. They'll be taking up most of the rooms at Wakefield for the NJW 2010, so if you're thinking that you'll probably come to 'THE BIGEE' you'd better get on with booking it.

[Alastair Gregg]

Hello Tony,

Can't help with the half shafts, but I have just sent off my money and booked. I just hope the hotel is big enough, or if not thatr there is another near by to give people the chance of taking a full and active part.

They were all very keen on coming in May when I was with them earlier this week.

[Tony Fearn]

Thanks George for the help with the 'where-with-all' about the back axle.

When I investigated, it seemed as though the bearing had siezed and as a result the half shaft was turning in the inner part of the bearing, so the balls were not moving at all.

This being the case, the half shaft itself was wearing away in the bearing, causing a reduction in its diameter, so that's where the play was when the MOT inspector noticed it, and it wasn't actually the bearing itself.

The shaft and the bearing had of course to be replaced and George's email about the relevant section of the Jowett Manual was of enormous help.

What I like about our Pre-war vehicles is that they are just like a giant Meccano set. If you sit down and think about it, there's not much that can't be sorted with a screwdriver, a set of BSF spanners and a large hammer.

This being said, the replacement of a half-shaft is a rather specialised procedure. I was going to have a go at it, but I'm grateful that Mike K. came to the rescue for this job, as I didn't have the tackle to drift out the various bearings.

About 20 years ago, on one of my two visits per year to Roy and Bessie Braddock down in North Rode, Roy suggested to me that sometime in the future I might need a half shaft for 'Mary Ellen' and that he just happened to have one in stock. (Memory Lane anyone?)

As usual I took his advice, bought it, and here we are!! I also bought a diff. pin and some rear wheel bearings at a later date, and these were also used in the re-build.

Another thing is, that when you've spent so much time and effort sorting out such a problem, there's nothing to show. It's not like re-painting, or re-chroming etc.

So 'Mary Ellen' is now roadworthy again, and thanks to Bob Mercer who helped me to re-line the rear brakes with linings bought a considerable time ago at Beaulieu's National Autojumble, (when I used to front the 'JOWETT' stand).

Nowadays we are so fortunate to have the services of the Jowett Car Spares lads who source and dispense such necessities. Last week I bought a couple of new-old-stock layrub couplings from JCS to replace the worn ones on the prop shaft and they have made so much difference. There are still a few in stock, so if yours are a bit dicey, and taking note of my ramblings above about laying in necessary spares for the future, it might be worth ringing JCS and ordering a pair.

Tony.

[ian Howell]

Tony et al: -

It may be possible (and possibly worthwhile) to have the damaged part metal sprayed and reground. After all if it's good enough for crankshafts . . .

Assuming the groove does not occupy a significant proportion of the shaft diameter, it must be worth thinking about.

Anyone any comments? (As if!).

[Drummond Black]

Ian / Tony, From what I gather from Tony's descripition of the fault the half shaft should be able to be reclaimed. Metal spraying falls into two catagories. 1. Hot Spray ( base metal temperatures around 700 - 800 C ) 2. Cold Spray ( base metal temperatures around 150 - 250 C )

The half shaft would have to be reclaimed using the Cold Spray Technique. This method uses a exothermic ( or micro weld ) reaction to fuse the powder, fed into the oxy-acetalene flame, onto the shaft. After spraying the shaft is turned or ground to size to take the new bearing.

I use the equipment in the workshop for many jobs on the Jowetts. The king pins on the Jupiter were sprayed with a .030 bronze coating and machined to standard dia. I then made stainless steel bushes to fit into the stub axles. They have been in the car since 1994 with not a sign of play and NO RUST.

Drummond

[ian Howell]

Have I spotted a 'niche' market opportunity for you here Drummond!?

I bet there are a number of Jowetteers (possibly including JCS?) who have items that might be recoverable by someone with the kit and sympathy.

Any thoughts on the pinion on my old steering column?

The teeth are worn down to knife edges and I don't have a 'form' cutter that would replicate the original tooth profile, BUT . . .

A straight rack has straight sided teeth and the original teeth were very crudely milled - not ground, so careful application of straight sided file . . .

Also, the gear is brazed onto the shaft. Now, what brazing does to hardened gears is well known, so presumably the gears were not hardened.

No wonder they wore out!

So, with 'soft' teeth and a lot of patience it might be possible to re-cut the teeth by hand?

Or, alternatively . . . .