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

[Big D]

Hi all,

I was reminded recently that it has been many months since my last update. I have been tied up with work on an M20 and a White Scout Car, and now I am in the process of moving house and workshop. It could be a while again before my next update but here’s a rundown of a few things I’ve done recently.

I had seen wartime photos of the ammo trays for the .50 cal ammunition fitted onto the M8 gun rings. I had been given a NOS ammo box tray (thanks Mike) and wanted to make use of this so I fabricated a bracket to mount it. From what I’ve seen on wartime photos, just about anything seemed to go for mounting the ammo box trays around the gun ring, so I just came up with a simple bracket for mounting that tray to the gun ring. The clips on these trays are too short to use the M17 ammo boxes so I painted and stencilled some standard .50 cal ammo cans and will use one of those in the tray.

Thanks to Jon and Dave, I received all the parts to make up the 37mm cleaning rods. I do have some bits and pieces for these left over if anyone needs them.

I picked up some R-14 receivers which I have added wiring looms to (thanks again Jon). I have fitted these to the tanker’s helmets which I will use with the interphone on the vehicle. This setup will be better than the HS-30 headsets I have.

I’ve added a water can and NOS MS aerial set in a BG-56A bag to the vehicle as well as picking up the correct type of oil can for the engine bay. I also picked up some NOS legs for the barrel on the automatic choke linkage.

While the M8 has been sitting I noticed that hydraulic fluid had been seeping from the throttle master cylinder. I hadn’t been too concerned about it as this M8 had a piece of the floor missing in that area which I had covered with a plate and the fluid had been leaking through there and onto the floor of the workshop, rather than pooling in the vehicle. I know need to get onto repairing this. The master cylinder that I had used was a NOS one but that had lasted only 18 months or so before it started leaking. Rather than removing that master cylinder and rendering the vehicle immovable, I decided to pull out the other master cylinders I had and rebuild those. I have about five of them but only one looked like it was NOS but pretty rough in appearance. I managed to track down some NOS rebuild kits for these and the cups in these kits look to be in really good shape. I decided to send the cylinders off to my brake specialist and he is going to sleeve a couple of the cylinders and rebuild them with the new kits. I need one for the M8 and one for the M20.

I’ve also noted that my brake woes aren’t completely over. One or two of the wheels have some slight seepage from the wheel cylinders but the front wheel on the driver side has a good leak and is leaving a pool of fluid on the floor. You might recall I used English made wheel cylinder cups on the wheel cylinders on the co-driver side of the vehicle, and Spanish made cups on the wheel cylinders on the driver side. I would have to say the English made cups look to be holding up much better. I don’t intend to tear down that wheel assembly at this stage and will sideline that job for later on.

That’s it for a while again. I’ll pick things up again once we are settled into our new place.

[Big D]

More photos.

[Big D]

Hi all,

It's again been many months since my last update and I'd had some questions about how the M8 was going, so I thought I'd let you know progress.

Due to all the cancellations after the Pandemic, prior to this last weekend, the M8 had only had one public outing. This last weekend was the Warbirds over Wanaka Airshow in the lower south island of New Zealand and the M8 was on display there.

There were some good Warbirds aircraft on display there including the latest De Havilland Mosquito that has been produced in New Zealand. Now that the show is finished, the Mosquito is being dismantled for transportation to its new owner in the US.

As you know these vehicle restorations are never complete and there will always be something to do on them. The M8 has had very little use and barely a few miles on the road since its restoration. It was good to get it out again and get a few miles on it to identify any issues with it since I put it all together.

In its limited use around home and that previous event, I’d already found a few things on it that I wasn’t happy with. Most of the issues are teething issues so in that sense I’m pretty happy.

I think I had previously mentioned it, but the NOS throttle master cylinder I had installed started leaking within about 18 months of its installation a few years ago. I have just kept the reservoir topped up during that time but it has been bugging me and some paint is being damaged now, so it is time to pull it out now and sort that out. I have had a hydraulic specialist rebuilding a couple for me. One of the rebuilt ones has gone into an M20 armoured car I am restoring and the second will go into the M8. I’ll then get this one rebuilt as a spare.

While we are on the subject of hydraulics, you might remember that when I last did the brakes, I had to put English made cups in the wheel cylinders on the driver’s side, and Spanish made cups on the co-driver’s side. One of the wheel cylinders on the driver side with the English cups started seeping pretty much straight away. I see now the rear wheel on the driver’s side is also weeping so it looks like I will have to do the driver’s side again, this time with the Spanish cups. The wheel cylinders on the co-driver’s side all still look good, so the Spanish cups are working well.

Selecting reverse on the M8 has been tricky since it’s rebuild. That is, it just won’t select reverse at times. I’ve tried a number of things to see where the fault may have been, including easing the clutch out a little while keeping pressure on the gear lever into the reverse position. That didn’t work. I wondered if the clutch might be slipping a bit but starting it in gear with the clutch in doesn’t result in any movement in the vehicle.

I’ve been under the vehicle and removed the long rod from the gear lever assembly in the vehicle and tried selecting reverse from the selector on the side of the transmission. That didn’t work either. Often, sitting there, working the transmission into a different gear, then into neutral, then into another gear, then into neutral, and then it will go into reverse. Strange…

I did notice that this time driving the M8 around, that the reverse problem was better and although I had a couple of occasions where I couldn’t get it into reverse, there were more times (than not) that it would go into reverse. I think that is due to the fact that the vehicle is being used more, and the gears are working better with each other. Have others had this problem? Ultimately, I believe it is in the gears themselves and I wonder if having new gears meshing with old gears mightn’t be helping.

As an aside, I have rebuilt the transmission for the M20 and that is sitting here. I have the top of that off now so will refamiliarise myself with how this transmission works to see if that gives me any other clues.

On the right rear side when driving and turning, the vehicle is a bit creaky. I’m not sure where that noise is coming from yet. I suspect it might be the right rear lower torque rod. When I restored the M8 I couldn’t find an original piece and ended up modifying one from another vehicle. The fit was never perfect so I need to investigate that further. I see there are NOS ones popping up for sale.

I noticed when driving over the weekend, that the steering was a bit skittish when driving. A tighten up of the four bolts on the steering box mount solved that problem.

You might recall that the 37mm gun I got with this project was damaged. The turret and the gun had been on a range and the tube had been damaged. We straightened it in a press but the internal bore of the tube was almost fully blocked. I now have a replacement gun to fit in its place. This came from Europe and was clearly a demilled gun as the tube has been cut and rewelded (not very well) just past the sleigh. The gun appears complete and the action works, so that will be in improvement on the existing gun. My plan is to get the tube cut again, a thread machined on each end, and then rewelded once the two pieces are screwed back together. This will reduce the length by about 10mm but that won’t be an issue. This won’t be firing live rounds but it will go bang with some blank rounds.

There is a noise in the engine bay that I haven’t been able to identify yet. I’m not sure that it is a metallic sound but it is coming from the radiator end and is in tune with the engine revs. I did wonder if one of the fan blades was rubbing against the fan shrouds. That doesn’t appear to be the case though. I will continue to investigate this.

Apart from that, all appears good. The M8 is a real eye catcher and always generates lots of interest when it is on display. While the vehicle was in display last weekend, I had a couple of children asking if they could come up and have a look in the turret. Of course I said yes, and got them up for a look. Once they had finished, I looked down and there was a queue of about 10 children all wanting to do the same. After about 100 children (and a few mums!) later….. I said I needed a break and I stopped the little tour.

The engine starts just about first time, every time. It sounds great idling and when revving. I do need some practice changing gear in it though. I’ve found once you get into second gear, it wants to accelerate. However, I’m too slow changing from second to third gear and the vehicle slows rapidly as I’m trying to get it into third gear. As I say, more practice required.

After this weekend’s display I decided I wanted to change the look of the M8 and remove the sandskirts. I certainly think it looks better like this...

That’s all for the moment.

[Big D]

More photos....

[David Dunlop]

Hello Darryl.

Nice to hear you are finally having some fun with the fruit of all your labours.

Could the source of the engine compartment noise be an air flow issue rather than a mechanical/contact type issue. In other words could the sound be getting generated by the air moving around. past or over something like a bent shroud or object that is not quite in its correct location?

Could you try just removing the fan blade assembly to eliminate the air flow and see if the sound is still there. If it is still there, the lack of air movement might help better isolate exactly where the sound is coming from.

Best regards,


David

[Big D]

Hi David

Thanks for the reply. You might be right that it is air rather than mechanical. I'm pretty sure it has been there since day one and it seems to be more toward the co-driver side corner. It did sound a little like the sound you get from the top of the vacuum fuel pump before I plugged the output that would be for the window wipers. A sort of 'phit,phit....'

I've uploaded a short video clip. Not sure if that will help but you will probably get the idea:

https://youtu.be/4xx4TLfZWW8?feature=shared

[Big D]

Here's another longer video. I'll have a closer look in the other side of the engine bay when I get some time:

https://www.youtube.com/watch?v=I2BYBDALI30

[Tim Bell]

[QUOTE=Big D;296045]Hi David

Thanks for the reply. You might be right that it is air rather than mechanical. I'm pretty sure it has been there since day one and it seems to be more toward the co-driver side corner. It did sound a little like the sound you get from the top of the vacuum fuel pump before I plugged the output that would be for the window wipers. A sort of 'phit,phit....'


I had a similar sound on my white scout car... turned out to be a head gasket issue.

Tim