A 969 rebuild from Downunder.

Military Trucks 2 1/2 ton and greater, Wanted, For Sale (NO AUCTION or EBAY), and Knowledge Base
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kw573
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Posts: 882
Joined: Mon Aug 11, 2008 11:48 pm
Location: Near Bundaberg, Australia.

Re: A 969 rebuild from Downunder.

Post by kw573 » Tue May 15, 2018 1:53 pm

More . . . .

This is how it looks now . . . nice.

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And then, suddenly, it was time to start on the cranes. There are still lots of small things to do on the truck, but time to size up this job.

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First thing was to strip out the transmission to see what I had.

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. . . . hmmm, not good . . . .



Sam.
1942 Script GPW (Daily driver).
Willys MB.
2 x Diamond T 969.
Kenworth M1A1 Heavy Wrecker.
3ton GS (Blitz) Trailer.
150gal water tanker trailer.

kw573
G-Major
G-Major
Posts: 882
Joined: Mon Aug 11, 2008 11:48 pm
Location: Near Bundaberg, Australia.

Re: A 969 rebuild from Downunder.

Post by kw573 » Wed May 16, 2018 2:32 pm

More pictures that I missed posting earlier.

When repairing the inner mudguards (a.k.a. Engine side panels), I needed to replace some caged nuts.
This is how I made the nuts. In 1/8" M.S. plate, I marked out, drilled and tapped the 1/4" UNC holes first, then cut them with the wafer disc.

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The new nuts with an original one to compare.

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While deciding what to do about the odd sized steering wheel nut, I had to identify the thread. Being a Ross brand steering box, I knew it would be a UN series thread. So measured the O.D. (outside diameter) using my trusty Dial Gauge. . .

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. . . and the 'pitch' of the thread using a 'Thread Pitch Gauge'. I could have measured, say, ten pitches and done the maths to find the T.P.I. = Threads Per Inch. (Metric threads use the actual pitch = distance from the top of one thread to the top of the next thread.) This was when I realized that I had a non-standard thread. It was finer than both U.N.F. and U.N.S. (special).

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Fortunately, the lathe I have access to has a setting for that pitch. The first job was to turn out the I.D. which took a bit of working out, I allowed 0.010" oversize for root clearance, and that worked fine.

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Still haven't got a fix for my Surfacezero problem. Can I fix it with the MIG welder? :?

Have a nice day.
Sam.
1942 Script GPW (Daily driver).
Willys MB.
2 x Diamond T 969.
Kenworth M1A1 Heavy Wrecker.
3ton GS (Blitz) Trailer.
150gal water tanker trailer.

kw573
G-Major
G-Major
Posts: 882
Joined: Mon Aug 11, 2008 11:48 pm
Location: Near Bundaberg, Australia.

Re: A 969 rebuild from Downunder.

Post by kw573 » Thu May 17, 2018 2:14 pm

Hi all,

For some reason, I did not do this "shift plate panel" when I was doing the cabin panel work. Using 1/8" plate, I folded a 'U' shape along the rear edge as it is open under this. Strangely, I have seen at least two designs of this part of the cabin. The other design has a vertical plate from the rear edge of this panel to the floor, but the seat base is open to make a little hidey-hole under this shift plate panel.

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It was surprisingly tricky to find the correct curves and angles, back and forth with scissors and cardboard. I used this profile gauge to find the trickiest part.

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Still more back-and-forth to get the angle and distances correct. Then paint and bolt it down with 1/4" UNC round head slot drive bolts and nuts, three along the front edge and one from the outside of the cabin at the rear of the panel. One more job done.

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Also, here is a picture of the finished tail light. Next time, I'll drill the bulb holder higher in the back of the insert so as to have the bulb filament level with the middle of the lens. Sorry about the shadows.

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At the left of this picture (above) can be seen the left side hook anchour loop (anchour = Australian spelling) which I made recently. I had made the right side one a long time ago. They are designed to bend open if too much power is applied, instead of bending and breaking something. Good idea as in the military, I guess that there was no guarantee that the operator would be competent.
This is how I set up to make the first bend. I had to be careful as I used heat and didn't want to damage the socket.

Image


Enjoy.

Sam.
1942 Script GPW (Daily driver).
Willys MB.
2 x Diamond T 969.
Kenworth M1A1 Heavy Wrecker.
3ton GS (Blitz) Trailer.
150gal water tanker trailer.

kw573
G-Major
G-Major
Posts: 882
Joined: Mon Aug 11, 2008 11:48 pm
Location: Near Bundaberg, Australia.

Re: A 969 rebuild from Downunder.

Post by kw573 » Tue May 22, 2018 12:57 pm

Hi all,
I have stripped out the Holmes transmission and this is what I've found. As with most of the gear cases I've opened on this truck, I looks like it has never had lube added (beyond assembly lube) when last re-built! Makes me wonder what happened to this truck in the past.
Condensation has done its' damage!

The brass worm wheels seem to have very little wear . . .

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. . . however, the steel worms which are in the bottom of the case have been in the buildup of moisture from condensation and are badly corroded for a small section of them but on every tooth.

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So I tried to use a puller to dis-assemble the shafts, but it was very tough work . . . .

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. . . . so I used a press and they came apart easily. I was a bit surprised that the puller was good for only a ton or so of pressure. The press I subsequently used registered barely 4 tons and they came apart easily. I need a press!!! Anyone know where I can buy a 60ton 'Servex' press (or similar) in Australia?

Anyway, here is what I had.

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And all cleaned up.

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There are 6 bearings and 1 seal, all stuffed, of course.

Enjoy.
Sam.
1942 Script GPW (Daily driver).
Willys MB.
2 x Diamond T 969.
Kenworth M1A1 Heavy Wrecker.
3ton GS (Blitz) Trailer.
150gal water tanker trailer.

kw573
G-Major
G-Major
Posts: 882
Joined: Mon Aug 11, 2008 11:48 pm
Location: Near Bundaberg, Australia.

Re: A 969 rebuild from Downunder.

Post by kw573 » Wed May 23, 2018 1:57 pm

Hi everyone,

I've started some prep work on the Holmes transmission . . .

Image


. . . then had a look at the worm shafts. Badly corroded. I'm tempted to have a go at welding them some time in the future and then chase the thread in a lathe. The pitch is 3/4" = 1 1/3T.P.I.

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So I stripped out the transmission of a second set of cranes only to find a different situation of corrosion. This set had oil in it, keeping the worm shaft clean, except the top third was above the oil and so has deep surface rust. Nowhere near as bad as the original set. Realizing that the steel is quite soft (center punch test), I tried to file the rust off and got this result.

Image

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It is a bit hard to see in the pictures, I have managed to file the worm enough to have maybe 80% clean metal on the face of the tooth. The remaining rust pits will act as oil reservoirs, like hone marks in an engine bore . . . I hope. Also, I inspected the undamaged tooth faces and was surprised how poorly finished they were. My concern was that under working pressure, the edges of the pits may broach (scrape) the brass worm wheel. The more I think about it, the more comfortable I am with this solution.

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And this is how the worm shaft and worm wheel work together. I haven't calculated it, but the gear ratio of this gear set is probably around 30:1. Although it is not true, from a theory point of view, the worm won't drive the worm wheel thus making it a self locking drive, a great benefit for winching. However, on more than one occasion I have had a worm wheel drive a worm shaft under load, thus reversing the winch. That could be disastrous at the wrong time!

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So far, so good.
I have lots of paid work right now, so not a lot of workshop time happening :( .

Have a nice day.
Sam.
1942 Script GPW (Daily driver).
Willys MB.
2 x Diamond T 969.
Kenworth M1A1 Heavy Wrecker.
3ton GS (Blitz) Trailer.
150gal water tanker trailer.

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