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

[Big D]

Hi all,

I’ve been continuing with the wiring on the M8 over the last week or so. I first had to spend some time vacuuming out the channels in the hull where the wiring and hydraulic lines go. It’s amazing how much they fill up with the grit from the blasting.

The instrument panel wiring is in now and the instrument wiring is connected to the rear terminal box. I’ve also been putting together the front wiring assembly. I didn’t have all of the original conduit so I’ve had to make a few pieces up and thanks to Willy for his guidance on these. I think what I’ve come up with is pretty close to correct. I am still needing a couple of the conduit unions for the brake light switch which I will keep an eye out for. The conduit I have for the compass is pretty worn so I will make up another piece for this.

I still need to connect the wires to the correct terminals on the headlight switch. Can anyone confirm what the different abbreviations on the headlight switch shown on the photo stand for?

Is this correct?

SS = Service Stop lights?
S = Service Head and Tail?
BS = Black out stop lights?
HT =
TT =
BHT = Black out head and tail lights?
B =

What do the others stand for? Is 'B' for battery? The circuit diagrams in the manual give terminal numbers on the headlight switch, but not the corresponding abbreviation above. There should be 6 different connections to the headlight switch so I''m keen to get this right first time.

The 12 volt power supply line to both sponsons for the radios is installed now along with the wiring in the junction box on the engine cross member. Can anyone confirm the wiring conduits that come out of this junction block? I have cables for ‘Gas’, ‘Oil’, ‘Temp’, ‘Solenoid’ and overhead filter to the coil. Is that correct? I am actually missing one of the wee plates as per the photo if anyone has a spare.

I’ve found that the conduit for the siren has to be in a very tight curl to get it to fit, so I will need to experiment further with that.

I’ve talked to the engineering guys who are doing the spark erosion on the two screws holding the recoil system onto the mantlet. They think the screws are too big for that and are looking at other options. I’ll let you know how I get on.

Thanks to Seacon, I’ve finalised the Company and Troop markings so will get the stencils for those sorted out ASAP.

The hull is going to be moved in the workshop this week which will allow me better access to it and I hope to have the front axle and springs fitted in the next week or so.

[Big D]

More photos.

[Big D]

Hi all,

Over the last couple of weeks I’ve been finishing a few jobs off and tidying up a few things up that I wasn’t happy with. I managed to get the M8 shifted around in the workshop. This gives me much more space around it to work on and will make life easier getting the axles in place.

The radios are in, pending me doing a test on the interphones to see if it all works. I’m charging up a battery now for the test. Fingers crossed it works. I’ve tidied up the instrument panel wiring and it is sitting in place, also pending testing. Hopefully all is connected correctly there as well!

I’ve started reassembling the front axle, starting with making up and fitting some new hydraulic lines. I had to fabricate the small mounts that hold the flexible brake lines where they connect to the fixed brake lines as I couldn’t find any of those. I have some nuts coming that secure the flexible lines to these small mounts.

The rubber boots on the axles were damned hard to get on. A real tight fit, but I got them on. I have the axle shafts in but I forgot to take the grease (!) to the workshop so I’ll do the axle shafts and joints tomorrow as well as fitting the sleeves and bushes that secure the steering knuckles to the axle.

One thing I have noticed that I don’t have is the nut which secures the Pitman arm lever to the steering box. This is a bit of an oddball size of 1 1/8”- 16 UNF and I don’t have one. Does anyone have one lying around in their box of bits and pieces?

I’ve just started on the hydraulic lines for the brake and clutch master cylinders. This is going to take some time with me not having any original lines to work off.

That's it for now...

[Big D]

More photos.

[Petr Brezina]

Outstanding job!

[Big D]

Hi Petr,

Thanks for that.

[Big D]

Hi all,

Here is the last bit of work I’ll be doing before I skip over to France for a couple of weeks. I’ll be hitting the military fairs in Normandy so fingers crossed I pick up some of those hard to find parts.

The front axle is now complete, minus the nuts for the brake lines, which are coming. Brakes shoes, slaves cylinders, lines etc are all fitted. As I said last time, those rubber axle boots were dogs to put on. I thought the inner part of the boot was hard to put on, but the outer part was even worse. The boots I used were NOS halftrack ones and they were very stiff. I had to remove one that I had already half fitted and clamp it in a vice with some bits of wood and heat it up with a heat gun to stretch it. That got it on. I left the other side on and heated that up with a heat gun as well. I was then able to stretch the rubber enough on that to get the outer part of the boot on the steering knuckle. I’m told (thanks to Willy) that the best boots to use are the ones for the REO trucks. I don’t think it will be an easy job to ever replace these in situ, but if I ever have to I’ll be using the REO ones.

You’ll see that one of the slave cylinders is marked with a nylon tie The guy who put the stainless steel sleeves in the cylinders said that this cylinder has a split in the body. It shouldn’t affect the operation with it being sleeved, but I will keep an eye on that. The axle is sitting on a dolly now and I’ll slide it under the hull and fit it all when I get back.

I hooked up a 12 volt battery to the wiring to test the driver and co-driver interphones. The BC-604 transmitter and BC-603 receiver both started up as expected, but I noticed that the dynamotor on the transmitter was running all the time. I tried the driver and co-driver interphones with T-30 microphones, SW-141 chest rigs and HS-30 headphones fitted and neither worked. Bugger...I then plugged a T-17 microphone into the transmitter and that gave me audio at the two interphone stations. Okay, some progress, I thought….

I went back to the wiring diagrams I had. As you can see there are three slightly different versions of the wiring for the BC-606’s on these diagrams. I was just about to try rewiring them to one of the other versions when I noted the jumper on pins 6 and 10 on the connector on the FT-237. Two of the diagrams had the jumper on the FT-237, with corresponding differences at the BC-606’s. The diagram I had used though was the one out of TM 11-2702 and this did not have the jumper. I removed the jumper off the FT-237 terminal and straight away, I could transmit from the T-30 microphone on the co-driver side and hear it on the driver side. I noticed to that the dynamotor on the BC-604 was only running when the microphone was keyed which is correct. I tried transmitting from the driver’s side next but couldn’t hear audio at the co-driver’s side, so I obviously still have something amiss there. Whether it is a fault with the headphones I tried, or something internal in the BC-606, I’m not sure. I was out of time then so when I get back to the workshop I’ll work on that some more.

The T-30 microphone, by the way, seems to work really good. Much better than the T-17 microphone I thought.

Anyway, progress, but more work to do.