M8 restoration
 

More photos.

JXD crankshaft shims.
 

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.

M8 restoration
 

Hi John

Thanks for that. Interesting about the JXD. I hadn't heard about that before.

M8 restoration
 

Hi all,

Here are a few photos of what I’ve been working on over the last week.

Thanks to Willy for confirming the black rubber type spacers are the correct one for the headlights. These spacers do have a slot in the middle for the top rim of the headlight sleeve to fit into. When fitted on the sleeves, they need a bit of downward pressure into the hole in the hull so that the brass bush in the handle hole can be pushed through to lock the sleeve in place.

I have the fuel pump and fuel lines fitted in the front of the hull now. The line in the foreground of the photo would normally be at the very front of the hull but it seemed to fit nicely as I have it so I left it at that. I used a bit of thread sealant on all the connections so hopefully all will be well with them.

The reassembly of the intermediate and rear axles is progressing. I’m now at the stage of making up the fixed brake lines for the axles. I have no templates so I am working off photos and the plans from the parts manual to do these.

Does anyone have any axle brake T connections spare that they would be prepared to part with? I have fitted four of the six required but the other two I have are both used and have damaged threads. Originals seem to be very hard to find. Can anyone assist please?

What is the easiest way to install the intermediate and rear axle? The manual says that the back of the vehicle needs to be lifted to a height to get the two axles under it. I guess then it is just a matter of aligning the ends of the leaf springs with the two openings on each of the axles.

My plan was to get the boys in the engineering workshop next door to bring in their truck and hiab crane. We’ll lift the front of the hull and then fit the front wheels to the front axle. Then we can lift the rear of the hull enough so that I can roll the intermediate and rear axles under the hull.

Once the rear leaf spring ends are in the slots on the axles, will the weight of the hull settle enough on the axles to stop them moving around, or will I need to get the torque rods locked in straight away?

There is not a lot of information in the manuals about the torque rods in the manuals, and how they are fitted and adjusted. Has anyone got any first-hand experience with these? Are the top ones adjusted simply to keep the alignment of the axles correct?

I’ve noticed that the handbrake cable is a real bugger to fit into place on the hull side. The cable comes down tube in the side of the hull and has to make an almost 90 degree turn to go into the mount on the hull. The cable is quite stiff so getting it to slide down the tube and then sideways into the mount is not easy. Does anyone have any bright ideas on this? My one is just into the mount but it really needs to go in about another ¾ inch.

That is all.

Merry Xmas.

M8 restoration
 

More photos.

M8 restoration
 

Hi all,

Xmas seems to have come and gone in a flash.

I have fitted the brake lines to the rear axle, along with the brake line shields that I had. I am missing one section of shield but will hopefully pick that up at some stage.

I didn’t have a lot of photos of the actual layout of the brake lines so hopefully these photos might help someone else who is doing them from scratch. The lines are a bit finicky to make to the right shape to fit the shields, and they need to have quite a tight angle to get around the shield and then up into the Tee connections.

I have found the brake Tee connections I need so they should hopefully be on the way to me shortly. I’ve made up the brake lines for the intermediate axle and will finalise these when the Tee connections arrive.

I have fitted the hydraulic lines from the front of the hull down into the engine bay area now. I still need to finalise the length of the extra sections for the bleeder nipples at the ends, and will get this done once I’ve finished all the rest of the plumbing.

A bit of a strange request, but can anyone post a photo of the underside of the pedestal headlights? I have the blackout headlight but want to confirm the pin configuration on the pedestal headlights so that I can finalise the headlight wiring connections in the front of the hull. I only have the one blackout light so not sure how the pins are configured on the actual headlight.

The paint stencils have arrived. Good fast service from Axholme Signs in the UK. A few engine parts also arrived.

While I am waiting for the Tee connections to arrive, I will do some work on the turret which is sandblasted and painted and ready for me to pick up. I will need to give the roller bearing surface on the underside a tidy up when it gets here, as it was moved along a concrete floor before it was taken to the sandblasters.

I’m looking at the best order to fit the gun parts. I have an idea that before the turret is fitted to the hull, it would be preferable to fit the gun cradle into the turret and the recoil system to the gun cradle. The barrel and sleigh could then be fitted into the turret (maybe through the back panel in the turret?) after the turret is fitted to the hull.

Does anyone have any thoughts on the best order to fit the gun?

That’s it. Happy New Year.

M8 restoration
 

More photos.

M8 restoration
 

Hi all,

The rear axle is now complete with hub, internal axles and drums and is ready to roll under the hull. I do need a breather for the axle so will have to see if I can find one of those.

The intermediate axle is awaiting the brake Tee connections which are on the way (thanks Mathijs). Apart from that it is also ready to roll under the hull.

I’ve now completed the hydraulic plumbing for the brakes, throttle and most of the clutch. The clutch is complete up to the engine bay area and I’ll finalise that once I get the engine and gearbox in. So far I’ve worked my way through about 45 metres (nearly 50 yards) of steel tube for the brakes, throttle, clutch and fuel lines. I’ll still need another couple of metres of ¼” tube to finish the fuel lines.

I was having a few issues finding a suitable connector for the 3/8” tubing to go to the throttle slave cylinder. The parts manual lists the fitting as: 11/16-20NF-2 x 5/8-18NPT which I’d never seen before. I thought I might have been stuck finding that but it sounds like I have located one and it is hopefully on the way. I also have the correct adaptors for the hydrovac ordered and on the way.

I fabricated a couple of mounts for the hydrovac. This allowed me to get that in place and finalise the lengths of all the remaining brake lines. I fabricated a couple of small brackets for the flexible hose connections for the front and rear axles. Both of these brackets were missing off the hull. Hopefully where I routed the front line won't interfere with the protective cover that goes over the transfer case.

On the subject of hydrovacs, I have only just realised my hydrovac is a single input and single output unit. I’m not sure how I formed the impression that it had two inputs and two outputs and what I thought was an input port on one side was actually a plug! The hydrovac does appear to be a second series Bendix but looks like it is for one of the models of halftrack.

As a result, I won’t actually need the second (¼”) line I made up to go from the master cylinder to the hydrovac. That was waste of a couple of hours of my life making that. Haha. This actually simplifies things a lot for me though. What I’ve done is to adjust the plumbing a little for the lines to the axles. I have put an extra Tee connection on the hydrovac output so that all axles are connected to that one output. The 5/16” line running from the master cylinder is now to routed to the input on the hydrovac. My plan is to temporarily connect the 5/16” line direct to the ¼” line going to the axles so I can bleed and test the brake system. That will at least tell me that aspect of it is working alright before I get the hydrovac completed and connected.

I may do some painting with some of the paint stencils next week before I get the hull up on its wheels. The hull is at a nice height to work with as it is.

I am still looking for a nut for the steering gear sector shaft if anyone can help. This is 1 1/8-16NF-3. The wheel nuts are 1 1/8-16NF-2 and the thread is very close, but not quite right. What are the differences between NF-2 and NF-3?

That is all for this week.

M8 restoration
 

More photos.

M8 restoration
 

Hi all,

I have the M8 on its axles now. Once I completed the final touches on the rear and intermediate axles, I positioned them behind the hull and got one of the guys in the engineering workshop to bring the crane truck through. We opted to lift the rear of the hull first and get the rear and intermediate axles in place first, before lifting the front of the hull off its blocks and putting the front wheels on. It all went pretty smoothly but it was still about 2 hours work by the time I dealt with positioning the axles and fitting the torque rods to hold them in place. Thanks to Willy and Reg, I found that I could use two of the tie rod ends for the adjustable torque rods that were already on the rear axle. There was enough movement everywhere to allow me to fit the adjustable rods to those ends and secure the other end on its pin.

I feel like I’ve reached another milestone with the restoration in getting it to this stage, and it is a good feeling to see it on wheels. I still have some work to do though in setting up the torque rods. One of the fixed torque rods I had (not an original) seems to have a slightly bigger diameter pin on the ends and it won't seat properly in the hole on the trunnion or in the axle, so I think I will need to find an original. I also ran out of time to tidy up the threads on the torque rod mounting pins before the truck arrived, so I still need to find a 1 1/4-12 die nut and tidy the threads up.

Out of interest, what type and capacity of jack do the M8 and M20 owners use to lift an axle and remove a wheel?

I need to get some more of the 7/16” axle stud adaptors as shown in the photo. These align the internal axle in the hub and are described as adaptors in the manual. I would have called them collets, but can anyone point me to a supplier for these? I see they are on EBay as part of modern commercial wheel stud kits but I haven’t found them sold seperately yet.

Before putting the M8 on its axles, I took the opportunity to put some of the paint stencils on. It was a good height to work from without the wheels on. I used water based flat white paint and applied it with a roller. The markings came out really well and I’m very pleased with them. The only issue I had was trying to keep the star decal on the front straight as it went over the two raised strips of steel that go across the front of the hull. I found the best way to deal with that was to cut the decal in a couple of places to get it to go evenly over those steel strips, and then cover the cut with some bits of masking tape. I got the odd bit of paint bleeding through in those areas, but that scraped off nice and easy. These were good paint stencils and I had good support from Tony, the supplier.

That is all for this week.

M8 restoration
 

More photos.

Axle shaft cones.
 

Hi Darryl, I would call the parts you require split cones, p presume they are the same as Ford trucks 1934==1953 , part # BB 1142 B. they are for 7/16 studs . Later , heavier axles use a similar but larger cone. I think I have seen them in Mac's catologue. If you ars stuck I may be able to source some in Wagga -Wagga, let me know.

Delayed response
 

Hi Darryl
In post 308 you asked if anybody knew the difference between -2 and -3 UN threads.
I only noticed the question today and had a look in a copy of Machinery's Handbook 1971
To put it simply the differences are to do with production and not maintenance. The numbers designate the class of thread in relation to manufacturing tolerances and should be compatible.
In relation to the axle flange collets, I can't guarantee that they are the same but the Studebaker US6 used those which probably means they were also used on the split diff GMC 6x6. Ross Prince may have them.

Dave

According to the GMC SNL, collets are used on the rear axle drive flanges. They are referred to as dowels and the Timken Detroit part number is TD-1246-X-232 General Motors part Number is GM-2124231

M8 restoration
 

Hi John

Thanks for that. I will check them out and let you know if I get stuck.

M8 restoration
 

Hi Dave

Thanks for that. That is interesting. The wheel nuts should theoretically fit then, with them being the same thread and pitch. Why they won’t, is a mystery!

I will keep searching....

Fitting nuts
 

If you are sure that the threads are the same nut=to-stud then you could try a trick I stumbled on with a car restoration.
I could not get the track rod end nut to run sweetly on to the tread even after I had run the correct die onto the thread and tap into the nut so in desperation I mounted the end vertically in the vice (soft jaws of course) put the nut on one thread and then filled it with Brasso. With very little working backwards and forwards the nut then ran on using fingers alone. I cannot explain what happened as the threads were bright and clean beforehand. I just assume that the mild abrasive in the Brasso removed something I could not see.

Alastair
F60S

M8 restoration
 

Hi Alastair,

Thanks for that. Good idea. After your post I recall someone who did a similar thing with some valve grinding paste. That might yet be worth a go.

Hi Darryl.

I went back to review your first photo post. The old girl’s come a long way from what you started with. She’s looking quite proud now back on her wheels, for the first time in however many years!

Nice that you have her original US Army ID. Be interesting one day if you were able to fill in the history gap from production to takeover by the Italian Army.

David

M8 restoration
 

Hi David

Thanks for that. Yes, I looked back myself and it has been a bit over three years since I started this thread. That's a lot of posts! It is very nice seeing it on wheels, and it would be great to learn a bit more about its history. Hopefully the historical data will keep on filtering out.

Darryl, what can anyone say except "SUPERB" you attention to detail and workmanship is second to none and you will end up with a vehicle that will last way past you and me but will always have your name on it. They are such a cool looking machine. Are you going to get you 37 gas firing as that would be the cherry on top.
Great work.
Colin.

M8 restoration
 

Hi Colin,

Thanks for that. That is quite a compliment, coming from a craftsman like yourself! They are a nice looking machine and I'm looking forward to getting it completed.

The gas gun does sound like a good option. I do have another 37mm gun coming from Belgium though. It looks relatively complete so blank firing is another option. We will see....

M8 restoration
 

Hi all,

Just a quick update on what I’ve been up to since the M8 has been on its wheels.

I’ve tidied up a few more jobs on the hull. I’ve fitted the shock absorbers and tightened the torque rods. I still need to source one fixed torque rod, as one of the three I have is not right. I also still need to find a 1 ¼”-12 die nut to tidy up one of the threads on the adjustable torque rod mounts on the axle. I added a new DM-34 dynamotor to the other radio and have now fitted that to the radio tray, so that setup is good to go.

I have fitted some of the data plates to the driver’s area in the hull. One of them is slightly too wide so I need to find a sharp guillotine and shave 1mm or so of the side of the plate without bending it. Does anyone know where this small rectangular data plate showing dimensions etc goes on the hull? I have a feeling I have seen photos of this plate on the hull but I can’t locate that photo.

I still haven’t got the turret back here to the workshop so I have started work on a few other things to keep the project rolling. There always seems to be multiple small jobs on the go…

The gearbox is in pretty good shape but there is wear to the synchroniser and ring for 1st and 3rd gears. I have located these parts and they will be on the way to me shortly. The bearings seem to be in good shape but I will confirm once I have the main-shaft out. I’ll shortly start disassembling the gearbox in preparation for the arrival of the parts.

I will get the radiator dropped off to a repair firm this week for reconditioning. The exterior of it suggests it has been through a war, but I don’t know what the internal condition is like, so it will be interesting to see what they say. I will clean up the radiator fan diffusers in preparation for the radiator coming back.

I used a grease/gear oil slurry as lubricant in the pillow block but noticed that it seeped a bit of oil from the keyways. After a bit of research I used the tip about fitting a bit of cork into the keyway, and sealed it with a bit of flange sealant. We’ll see if that works. I have also started on the transfer case and will show some photos of that next week.

That’s all for today.

M8 restoration
 

More photos.

M8 restoration
 

Hi all,

I’ve been busy with work and life for the last few weeks and I haven’t posted for a while, so here are a few updates on what I’ve been up to on the M8.

I have stripped and reconditioned the transfer case. Overall it was not in bad shape and I don’t think it has been that long since it has been apart. All the flanges came off easily which I’ve found is a good indicator. The gears had some light corrosion on them from the transfer case sitting around with little oil in it. As per the photos, some of the teeth on a couple of the gears had some pitting resulting from the corrosion from that sitting around. I have cleaned that up and the pitting shouldn’t create any issues.

The bearings looked good and just required cleaning. I cleaned up all the gears and flushed and cleaned the internals. I found some oil seals ‘off the shelf’ from a local supplier which were the correct size for the bearing caps. The same seal is required for the handbrake drum bracket but the fit on this was a whole lot tighter, and it needed some persuasion to get it in there.

I did notice a very fine hairline crack in the front axle declutch housing. Looking back at my pre-disassembly photos, I see the crack was there and just visible under the old paint, so it might have been there for a long time with the paint and dirt holding it together. I have covered it in some epoxy adhesive which should seal it. I made up new gaskets, and cleaned all the shims from each bearing cap and fitted them as they were. All clearances seemed pretty good. I cleaned up the rest of the transfer case and a coat of paint freshened it up nicely. Let’s hope it doesn’t leak!

I fabricated some retainers for the rubber mounting cushions out of a bit of channel with some angled steel which will form the mounting strips on the sides. I will finish the welding and tidy them up over the weekend and then hoist the transfer case up into place on the hull.

M8 restoration
 

More photos.

M8 restoration
 

The turret is back and looking quite nice, complete with that old battle/range damage. I had to clean up a couple of lumpy parts on the top of the bearing face, where the hold down roller bearings would run, that I had missed pre blasting and painting. I have fitted the 37mm gun mount and recoil system. The gun mount sits on two heavy pins, one at the top and one at the bottom, each secured by a 3/8” screw. It was a bit of a handful fitting the assembly on my own, but I got there. The barrel has been straightened and I will likely fit this along with the damaged breach while I await the arrival of a replacement 37mm gun which is in better shape.

I picked up some of the other parts which had been painted and fitted the inner front guards. I left a lot of the imperfections in them but the new paint has freshened them up nicely. Just fitting these inner guards changes the appearance of the vehicle again.

I have continued tidying up a whole lot of other little jobs. The data plate that needed to be trimmed to fit has been done and glued into place. I received the 11/16” hydraulic fitting I needed for the throttle slave cylinder (thanks Taylor) so that hydraulic line is in place now. I still need another tapered fitting for the master cylinder which is on the way. The back panel is now fitted in place. I have also fitted the master switch box and battery cable as well as the interphone boxes for the commander and gunner. I will wire up the interphone boxes over the weekend and give them a test.

I spoke to the engine reconditioner and unfortunately the bores on the engine block were too pitted for even a bore out to 0.020 pistons. I might have got away with 0.040” oversize but I didn’t have any pistons that size, so I have decided to make use of the 0.060” pistons I have here and we are boring the cylinders out to fit those. Does anyone have any 0.060” rings they want to part with?

I have located the gearbox parts I need and I’ll have those parts on the way to me shortly.

That’s about it for the moment….

M8 restoration
 

More photos.

M8 restoration
 

Hi all,

Here are a few pictures of the latest progress. I have fitted the recoil system and elevation system. I found the elevation system and sector gear on the recoil system had to be fitted at the same time. I had the elevation gear in first but I couldn’t find a way to fit the sector gear for the recoil system afterwards as there was just not the room to make them mesh unless installing them together.

The 37mm racks, map clips and binocular holder are fitted, but I will need to remove the rear 37mm rack to lift the turret onto the hull. As you’ll see the binocular holder is white. From what I could see these were white on earlier M8’s and then green on later ones. Someone may correct me on that.

The barrel is now straight and the good news is that the damaged part of the tube will be obscured by the sleigh. The breech ring is off and will require some rebuilding.

What is the easiest way to fit the barrel to the gun mount? My thoughts were to fit the sleigh onto the recoil system and then with the recoil system angled downwards, slide the barrel (minus the breech ring) into the sleigh. Is there a better way?

After cleaning up the channels, I test fitted the sleigh onto the recoil system with my fabricated brass channel on the sides. The sleigh will go on, but it will be a snug fit with that new brass.

I finalised the interphone box wiring for the commander and loader. The headphones on these worked straight away but the microphones did not. I worked out that the way I had wired the connector on the FT-237 radio tray (which was as per the TM 11-2702 manual) was actually wrong. I can recall when I did that FT-237 wiring, that it didn’t seem right that the microphone circuits (yellow and brown wires) for the back interphone boxes weren’t on the same line as the interphone boxes for the front. Anyway, I wired them together on the FT-237 and the rear interphone boxes now work fine with headphones and microphones.

I have some of the sheet metal back from the sandblasters, painted and ready to go. Unfortunately, the sandblaster got their wires crossed with the painting. The plan was to blast and paint the tool lockers, as they were ready to fit, but just blast and prime the big sandskirts, because I still needed to apply some fibreglass to them to improve their roughish appearance. The blasters got that the wrong way around and I have a pair of tool lockers which have just been blasted and primed (!), while I have some fully painted sandskirts which still need to be fibreglassed! Oh, well….

I spent a bit of time making the radiator drain plug access flap on the rear lower engine panel. The reproduction panel that I had didn’t have this hole cut in it. Thanks to Willy for his help on the design of this. I received a nice load of parts I needed in the post today (cheers Reg), including the radiator mounts, hydrovac tube and hydrovac repair kits.

The last of the bits and pieces are loaded up and ready to go to the sandblasters for priming and painting.

That is all for today….

M8 restoration
 

More photos.

M8 restoration
 

Hi all,

Progress continues…

I was about to fit the transfer case to the hull but have just found some original cushion mount retainers (thanks Nick and Charles), so I will wait until they arrive before I fit the transfer case to the hull. I filled the transfer case with oil. The front declutch housing took just under a litre of gear oil and the main housing took just under two litres. I filled to the point where oil was just coming out the filler. I expected the transfer case to take a bit more than that. Can anyone confirm? I don’t appear to have anything in my manuals which shows the quantities. Someone was reproducing lubrication charts for these a while ago. Are these still available? I messaged the seller without success.

While I was mucking around with the handbrake assembly, I realised that I didn’t have the bell-crank which is fitted to the hull, as shown in this picture I borrowed off the net. If anyone has one of these lying around in their bunch of spares, I’d be very interested.

I’ve painted the stars onto the turret. The rough surface of the turret didn’t make it easy to apply paint masks which meant that I had a bit of bleeding of paint on the edges, so I’ll need to clean those up. I’ve also added a few more waterslide decals to the hull and turret. The bullet hole in the star looks effective!

I got the handles and two locking levers made up for the engine covers. The handles were spot on but the rod used in the locking levers was not quite the right diameter, and they are a slightly loose fit, so I’ll get the other two made up with the correct diameter.

Now that I have some hydrovac kits (thanks Reg) I have started reconditioning the hydrovac. I don’t think these kits are exactly right for my hydrovac, but we’ll see how we go. The slave cylinder on the hydrovac is pretty rough internally. The main return spring was rusted inside the bore of the slave cylinder and removal twisted it, so I will need to replace that. At this stage, the piston is still stuck in the bore of the slave cylinder so I am soaking it in the hope of getting it out at some point. The bore will need a stainless steel sleeve so once I get it all apart I’ll get it off to the experts for fitting that sleeve. I have rebuilt the main cylinder of the hydrovac with replacement seals and that side of it looks alright at this point. I’ll finish the whole unit off once I get the slave cylinder back.

I am trying to finalise the bleed points for the hydraulics now. I want to fit a bleeder nipple to the end of the short hydraulic lines I’ve made which come from the T junctions, but I am struggling to find a fitting that will allow this. What have the guys who have done this used for such a connection?

I have the lockers front outer guards and some other parts back from painting now. I’ll pick up the gun tube, sleigh and mantlet next week.