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

[Big D]

Hi all,

I’m back on the M8 again after returning from France, albeit briefly, as I have an operation on my hand today so will be out of action for a few weeks.

I picked up a few things I needed while in France: NOS throttle master cylinder, return springs for the clutch and brake, NOS turret support bearing and an A62 dummy antenna. I saw a few M8 parts at the various swap meets there, but not a heck of a lot.

I had another tinker with the interphone system for the driver and co-driver. It turns out that the microphone I was using on the co-driver side was not working. I tested it again with a NOS T-30 microphone and it works fine, so that is good news.

I noticed that the NOS T-30 microphones straight out of the box were really sensitive and clear. They were much better than the T-17 microphones I had tried. I have a few older T-30 microphones that don’t appear to work though. Has anyone tried to repair these? I gather they work on vibrations from the throat. I prised one apart but it doesn’t look like there is a lot that is serviceable, short of replacing the microphone element.

I have the front axle under the hull now and springs fitted. When my hand comes right I will bolt the axle to the front springs. I had quite a battle lining up the mounting holes on the front spring mount on the co-driver side. It is a chunky piece of steel but must have a very small twist on it, and I had to open up a couple of the mounting holes by a mm.

[Big D]

More photos.

[Big D]

Hi all,

I’ve decided to get my intermediate and rear axles reassembled by a local truck mechanic. I could do most of the work myself but with the operation I had on my hand last week, I can’t lift anything heavy for 6-8 weeks, and that will really slow my progress down. I figure I might as well get these guys to do the heavy work in the meantime which will keep the project moving.

The rear axle needs blasting and painting and reassembly with a new pinion shaft oil seal and new gaskets.

The intermediate axle also needs blasting and painting, but it also needs the differential carrier bearings replaced (which I have), a light bead-blast of the ring gear and diff housing and reassembly with a new pinion shaft oil seal and new gaskets.

I am in the process of gathering up all the drawings and specs for the mechanic and was looking at the procedure involved in setting up the preload on the pinion shaft, as per the attachment. I guess the truck mechanic will have some sort of tool for setting that preload up.

What about any other form of setup between the drive pinion and the ring gear? What thickness gasket paper should we be using? What effect does the gasket thickness have on the backlash?

Another question – one of the axle housings has a good torque rod end still on it, as per the photo. I haven’t taken it off at this point. My question is, can the adjustable torque rods be fitted with the axles in place and that torque rod end still on the housing? I am not sure whether both ends of the adjustable torque rods have to be on and the complete torque rod fitted in one piece.

I am trying to get my head around that aspect of the reassembly of the intermediate and rear axles. It’s no problem to remove the torque rod end, but I will have to cut it off and I don’t want to unnecessarily remove it if it can be reused.

I’m still after a U bolt for the rear springs if anyone has one.

[Big D]

More photos.

[David Herbert]

There is no reason that the torque rod end must be removed from the axle as long as the rubber is still servicable and the thread is clean and undamaged. You could assemble the rest of the torque rod onto that end before offering up the axle with torque rod to the vehicle. It might even make manipulating the axle a little easier as it will give you a bit of a handle. Do grease the threads before assembly or they will never come apart again !

Hope your hand mends quickly, you will be amazed at how much strength you loose by not using it and it is very easy to strain muscles and tendons when you do start to do propper work again so you need to go easy for the first month that you think it is fit again. I know from when I chopped the end off a finger a long time ago. They stuck it back on but I was a long time before I had all my strength back and I felt it in my whole upper body as I had not been able to do anything heavy at all. I was very lucky because although it is a slightly odd shape it is fully functional and even has most of its feeling.

David

[Andrew Rowe]

Hi Big D, the preload on the side carrier bearings is achieved by the thickness of the gaskets, It is easier to set this up without the pinion installed. We laser cut 2 or 3 thicknesses of gasket paper for this process when doing Bren Carrier diffs. The local engraving shop could achieve this for us. Cheers ANDREW.

[Big D]

Hi David

Thanks for the reply. Yes, I wasn't sure if the torque rod would fit in the space available without having the ends already screwed onto it. I guess I will find out.

I had Carpal Tunnel surgery on the hand and I didn't think it was a big deal but the surgeon said that it can take 12 weeks or more to come right and not to push it. Your experience with hand surgery confirms for me that I will need to take it easy.