How To: Restoration of Ford M8 armoured car US Ordnance number 7373

[mark gillatt]

Rebuilt jxc block on milweb.

[Big D]

Hi Mark

Thanks for that. I checked it out and it seemed like quite a reasonable deal but I figure I have come this far with what I've got, that I will stick to it.

[Big D]

Hi all,

Most of my spare time this week has gone into completing the recoil system. This is the setup I used to put the recoil system back together. Others might have a better method but this worked well for me.

I used two pieces of 10mm plate at each end. On the coupler end, I cut a hole in the plate and welded an old bearing cup to the plate over the hole. The diameter of the cup was a good fit over that end of the cylinder. I welded another tubular piece of steel to the other plate to act as a locater for a ¾” socket to hold the nut on the end of the cylinder piston rod.

I used two 1 metre lengths of 18mm stainless steel threaded rod. The rod size seemed like a bit of overkill but it was all the local scrap metal supplier had on the shelf of a decent length, and the good bugger he is, he allowed me to take it home, do the job and then just return it.

I found that size of rod gave some reassurance when winding the tension up and compressing the spring and I wouldn’t recommend anything under ½” or 12mm. The 10mm plate was just starting to bend a little at the peak of the spring compression.

I got some brass folded up for the sides of the recoil system. I looked at buying brass channel but couldn’t find any the exact size. In the end I got a local sheetmetal fabricator to cut and fold some brass sheet. Unlike the original, the folding means there is a bit of a radius on the edges but hopefully with me using sheet that was slightly thinner than the original, this won’t be an issue. I used some 3mm diameter brass rod to secure the pieces to the cylinder. I will try the barrel sleigh on it soon.

An EBay search turned up a bronze bush of the same dimensions I needed for the mounting pin on the other side, so that is on the way to me. I am missing the little arm on the side of the recoil cylinder which I’m guessing is a valve of some sort, so I will find a suitable plug for that. I’ve noticed that the buffer pin on the head of the cylinder is bent, which is making it hard to screw this in, so I will need to straighten that.

I have the pedestal headlight mounting connectors completed and ready for hard wiring in the hull. Thanks to Willy for the electrical connectors and Paul for the black plastic housing.

That’s all for this week.

[Big D]

More photos.

[Big D]

Hi all,

I have the hydraulic lines for the clutch and brakes fitted in place in the front of the M8 now. I was in the process of making up the lines for the clutch using 1/2" tube, as per the manual. Copper nickel 1/2" tube is available in the US but not easily available here in New Zealand. I finally found a brake specialist here who could supply it, so I made up a template out of 3/16" tube and asked the brake guy to make me the same thing in 1/2" tubing. I wasn't confident I'd be able to fold the 1/2" tube without any kinks so figured I'd get a specialist to do it. The other lines I did in 1/4" and 5/16" came out good but the 3/8" was getting a bit difficult to bend without kinks.

When I spoke to the brake guys, all their 'experts' asked “why the hell would you need 1/2" tubing for that clutch application?” I told them that's what the manual says and that's what the M8 used, so go to it and make me it please! However, they came back to me later and said that while they could supply the ½” tubing they were having a real battle getting fittings for a 1/2" tube to match the 1/2" UNF thread on the master cylinder.

I told them about Malcolm's experiences (http://www.mapleleafup.net/forums/sh...ad.php?t=29422) in that his M8 had 5/16” hydraulic line for the clutch and it worked fine. The brake company owner came out and looked at my M8 and the master cylinder for the clutch and he also thought 3/8" or 5/16 " tube should do the job for the clutch. He went away and had a look at the connectors he could get and the only way he could get lines and connections to fit the ½” UNF thread on the master cylinder was to have a 5/16" line with an adaptor to bring it up to 1/2" UNF for the master cylinder.

So, to save any more mucking around I told him to go for it and make me that line in 5/16" which he did. Interestingly, he used copper-nickel tubing which they bent by hand. Hopefully it works for me and I will update how this works/if it works, once I am able to test it.

I still need to complete the hydraulic lines for the throttle master cylinder. I have used 3/8” tubing for the lines, as per the manual. It took me a while to work out that these master cylinders use a tapered fitting, presumably of some NPT thread. I’ve sourced the T connections for the bleeding area so I’ll post pictures of these once I have them all fitted.

I spent a heck of a lot of time stripping down one of the two engine fan pulleys I was working on. If I could have found one on the shelf, I would have just bought it, as it cost me days of work trying to get it all apart. This is the one that was heavily corroded when I got it and I soaked it in molasses to clean it up. It had all just about become one big piece of metal and it was a real pig to get it all apart. The molasses did clean the metal up but I think it getting into the insides of the pulley didn’t exactly help in my efforts to strip it. The retainer wouldn’t let go, nor would the little spacer between the retainer and the bigger of the two bearings, and nor would the spacer between the bearings on the main spindle. I had to make bigger and bigger tools with bigger and bigger levers to try and undo the retainer, but I was starting to worry about the stress on the housing and in the end I virtually had to destroy the retainer to get it out. If anyone has a spare (as per the photo), it will save me time and money making another one.

After finally getting the pulley housing apart, I can see that I was never going to be able to press the pin out of the bearings as the metal was all completely stuck together. Liberal use of a cut off disc was required in the end to get the spacer and what was left of the bearings off, but it is now rebuilt and ready to fit.

I picked up a pulley wheel that is a bit quieter than mine, along with another adjuster, so I cleaned them up. I’ve also done a bit of painting and tidying up of some other parts.

I am back to working on the other two axles next week and I’m aiming to have those on the hull in the early new year.

Does anyone know which of the spacers in the photos is correct for the headlights? Both types were sold to me as being for the M8. I see the metal sleeve that sits in the hull actually sits a little proud of the hull when the brass bush is fitted from within the hole for the locking pin. The black spacers have a slot in the middle which fits over the metal sleeve but with this spacer on, it would take a lot of effort to push the sleeve down far enough into the hole in the hull to get the brass bush in place.

That’s it for this week.

[Big D]

More photos.

[John Mackie]

Darryl. You are doing a fabulous job on the M 8. When did the crankshaft in my WSC I found that bolting up all the main bearing caps the crankshaft would not turn. After a lot of recearch I was conviced that the crankshaft tunnel was out. I had the tunnel line bored to a size that did not need the shims, I also had the conrods given the same treatment. It then went together very nicley.