TooTallMike

Correct as neither of those are agricultural activities. Same way you can drive a tractor on the road at 16 but only for agriculture, so no taking a girlfriend to the cinema in it or going to Tescos. - MG

Can we assume this is not a tractor or similar?, and that you are not going to be using it for agricultural purposes? A vehicle registered as Agricultural can only be used in connection with agriculture. This is often stretched to mean things like tree surgery and plant hire and it would take a test case to find out where the line is drawn. However you cannot use a Agricultural Vehicle to go to shows, or to the shops etc. My biggest worry would be that an owner who is prepared to stretch (break) the law in this way is unlikely to be the type who is fastidious about maintenance and roadworthiness. Some, if not all Agricultural Vehicles are entitled to use red diesel as they work off road, however again you couldn't do this in private use. Furthermore you would need to drain any red and thoroughly flush the fuel system to avoid problems if you got dipped. The Q plate isn't a big problem. Up to the 90s the DVLA (or whatever they were called then) slapped a Q on anything that wasn't straightforward to date. Nowadays they insist on verification, leading to age related plates. As I understand it Q plates are now only issued to vehicles such as kit cars, where the age is impossible to define. It is possible to change a Q for an age related plate through the usual verification process. Finally some insurance companies don't like Q plates because they imply there is some question mark over the vehicle's identity. However specialist insurers should be ok. - MG

It was immediately sold to a Mat owner who now has it in reserve stock. MG

The third was re-engining a Ward laFrance M1 with a 265hp 8.3l Cummins 6CTA and Eaton 6-speed ‘box. The project also included a complete re-wire including upgrading the lighting, and some brake work. The truck’s debut was at A&E 2016 and it has gone on to win ‘Best Heavy Truck’ at Headcorn 2016.

The second was re-engining a Federal 93 x 43 tractor unit. This involved the removal of a Belgian Army-installed AEC Matador lump, and replacement with a 5.9l Cummins 6BTA including intercooler. This was mated to the original ‘box and uses a custom-made clutch in order to work with the original linkage. This was followed by some axle work.

It’s been a while since I’ve updated this thread as we’ve been flat out. In between GMC brake rebuilds, LandRover repairs, Jeep restoration, truck maintenance and repair etc etc we’ve had three major projects on. The first was the recommissioning of an M151A2 imported from Vietnam. It had been taken to the owner’s local garage where they got it running and attempted to MoT it as received. It came back with the biggest failure list I’ve ever seen, running almost to a third sheet! They then said they couldn’t find the parts and advised the owner to find a specialist. After an appeal on HMVF we took on the job. A lot of work was carried out including a full brake rebuild, partial re-wire, welding, engine tuning and lots more, after which I’m pleased to say it flew through its test. Following that it was registered and returned to the happy owner after some gentle off and on-road testing.

Hi, I admire your ambition but you may want to consider the following: If you're worried about the hassle of bring a scabby one up to scratch you need to spend the money and buy the best you can get. You will spend every penny of the cost of a good one in sorting out a bad one, if not lots more. It is almost always cheaper to buy a finished vehicle than to do it yourself (let alone pay others to do). It's different if you're looking forward to the pleasure of doing the work yourself but if not you should put in the money up front. There's still no guarantee you'll buy well or be lucky but at least you'll give yourself a fighting chance. Buying something that's lived in a field and been used to crush cars for fun is almost certainly setting yourself up for costly failure. If you're after some quality father/son time and your time may be limited surely it's better to have something which isn't going to spend most of its time with you in bits while you curse the day you set eyes on it. Finally, tracked armour is a big boys game and there is no way to do it on the cheap so please be realistic about what you are prepared to throw at this. - MG

Hi, You could probably overhaul the existing engine for a fraction of the cost and effort of replacing it with a diesel. I've done a large number of diesel conversions so you can trust my judgement on this. There are masses of parts out there for Ford V8s. Starter motors can be rebuilt. Fuel pump replace with electric. If the engine won't start, bearings, rings or re-bore will still be far less cost and effort than engineering a diesel. That said I can fully understand why you may want a diesel so you could have a look at what the French put in them here: http://www.milweb.net/features/sumb.php - MG

Looks like there might be a diff in that axle so it could be a cut-down lorry chassis? - MG

Hi, Trucktyre (also called Commercial Tyres) at Gatwick do all my tyre changing at very reasonable rates and seem to be able to source tubes for anything. - MG

The truck is due to do around 300 miles in the next week so we'll see how it gets on. The electric pump can be heard to tick at the correct speed even when the engine is stumbling, plus the first time the problem happened the fuel tank had just been filled (there are two filters in the system both of which are clean, so I don't believe it was caused by dirt being stirred up). We've also seen similar problems with pin-holes in pick-up pipes, as well as objects of various types floating around in the tank and blocking the bottoms of pipes. FYI the comments about checking fuel level were a nudge towards a certain other GMC owner who recently suffered an 'embarrassment'... As for my on-going problem, I'll report as and when it breaks again :undecided: - MG

Alec, FYI they are identical trailers other than the plain old M101 has different brakes and hubs and only has the twin handbrakes. Body, chassis, axle, suspension etc are identical, as is rated capacity of 3/4 ton. The 5-stud wheels are as per Dodge M37, which is what they were designed to go behind. The 8-stud wheels match the Dodge M880, CUCV Blazer etc. which were some of their designated tow vehicles. You may be confusing the M101 series with the larger air-braked M105 series which was designed to be towed behind M35s. This is a much bigger trailer with a 1.5 ton load capacity. - MG

Sadly wiring the coil direct to the battery to bypass the entire electrical system was one of the first things I tried but it made no difference. Since its last brief hiccup, the truck has now done around 50 miles without trouble. I've left an in-line spark tester on it so if it plays up the owner will immediately look so we know if it's electrical or 'other'. One suggestion is that the alternator may be putting out too much voltage. I'd normally expect to see around 13.8V but it was 14.5V when I tested it a while ago. This is at the high end of normal output range. I need to test it again under more controlled conditions to confirm but could it be that it's cooking something? - MG

I wrote too soon! The 5-mile trip to the prom went fine, however on the way back it began doing the same coughing and spluttering thing. The owner pulled over and as he was trying to call me it cured itself and he drove home with no further problems. On Saturday he drove it 20-odd miles to the Capel show with no trouble. I've not yet heard whether he got back ok. Someone suggested excessive alternator output as I measured 14.5V at the battery at high revs. This does seem a bit in excess of the 13.8V I've always understood to be the normal maximum. However I have no idea if or how this could be the cause of the problem. I plan to fit a spark tester in line so that next time it misbehaves he can pop the bonnet to see if it is losing spark. - MG

In desperation I fitted the distributor from another working truck and now it seems to be ok. The points in the 'new' distributor were a bit burnt so I fitted the old ones out of the 'old' unit. This means that the following have been changed: condensor, bakelite insulator through body, rotor arm, cap, leads. We are leaving it for now as the owner is taking his daughter to her prom in it later this week. After that I want to swap the 'old' parts back in one by one until the fault returns. To answer some of the questions above, the electric pump has been on for over 150 miles now. More importantly though, the spark could be seen to be disappearing when the engine coughed, whereas now it can be seen to be consistent. Thanks to all who have contributed and i will update in a week or so when I've looked into it further. - MG

Thanks Degsy, I'll have a look. Sorry you couldn't make it to A&E, I enjoyed meeting you last time and hoped you'd be there again. - MG

Thanks Pete, I'll swap the distributor for the spare and if it cures the problem then that's something I'll bear in mind. - MG

One thing I should add is that it has a hideous blow from the exhaust manifold joint. The owner is reluctant to let me touch it this side of the show season in case of breaking studs. It doesn't make all this any easier but it's probably wise as they will break. We disconnected the fan belt and sprayed all around the inlet joints and couldn't detect a change in engine note so I don't believe it's got a leak 'in' anywhere. I know exhaust blow can cause issues with back pressure but I think the missing spark means this is not relevant. - MG

Hi Folks, I have a perplexing problem with a GMC which I would like to throw open to the masses. I hope I've covered all the tests we've carried out as I don't believe we've missed anything but here's hoping... Symptoms: The problem began a couple of weeks ago after the truck sat unused for a couple of days. The engine will start first turn from cold and tick over fine but after about 5 minutes will splutter and cough, and then recover itself. It will then tick over and after a shorter time will cough and splutter, then recover. As it warms up the periods of good running get shorter and shorter until it runs rough and eventually conks out. Once allowed to cool it will re-start and the process repeats. Initially I looked at fuelling as we've done some work to the fuel system (electric fuel pump, carb rebuild), but after swapping to a known good carb which was just as bad I put on a spark tester and discovered the truck is losing spark during the misfiring moments. All cylinders do the same, and with two spark testers the loss of spark can be seen to be occurring in two locations at the same time. To me this rules out plugs and plug leads. The sequence of ever decreasing periods between failure seems to me suggestive of something electrical breaking down under heat/load. What we have tried (in order of trying): replaced condensor voltage check at coil including during misfire periods (13.5V - 14.8V) replaced coil (yes it is a 12V coil!) replaced rotor arm replaced distr. cap replaced king lead replaced points checked LT wire from coil to distr. wired direct from battery '+' to coil wired direct from battery '-' to screw on distr. body checked insulation of LT post through distr. body trimmed tags on condensor terminal as we thought they might be earthing to the base continuity and resistance checks between points and distr. body etc. compression test showing all 6 to have good and similar compressions. These changes were performed one at a time and then tested, and the symptoms did not change throughout. All ign. parts fitted were new from Rex Ward. What am I missing...? The next move is to fit a known good coil, distributor and leads from another truck but I'll admit this is clutching at straws since we cannot find anything wrong with what is already fitted. Thanks in advance for any suggestions - Mike

Hi Pete, Sorry I missed your call but I was at A&E with poor phone signal. The air cylinder is only for disengaging the clutch when using the crane or winch. It isn't used when driving and shouldn't move. The pedal operates the short link rod with the two clevises (250mm-ish length) which is then connected to the shaft that passes into the side of the clutch housing. If you can release the clutch with a bar on the operating lever it suggests an adjustment issue as it seems the clutch itself is ok. Can you post some photos of the clutch linkage and cylinder showing what it looks like with the engine running and air pressure up, and then with the pedal pushed down? Maybe it's not releasing far enough and you can get away with it when cold because of the cold oil dragging. Once it warms up and gets thinner the drag will diminish. The 250mm-ish rod needs to be adjusted so that the release bearing is just skimming the centre part of the clutch pressure plate. That should give you the required travel. Out of interest have you investigated how many shims are present between the pressure plate and flywheel? - MG

Hi, Having done similar wiring changes to various M-series vehicles I can tell you it will be necessary to either modify the wiring loom or disconnect sections and bypass them. Modifying is much neater. The entire loom is designed to operate the lighting the American way so the functions are combined at source and therefore have to be separated from there. If you want to modify the existing loom you will need to identify 'spare' circuits running to the corners such as those for blackout/convoy lighting which can be adopted for the functions you need to separate out. Regards - MG

Would you sell the trailer on its own? Also, where is it located? - MG

I carry a chain block to use with the lifting shackle located above each spare wheel. That's fine at the roadside but mechanical help is much easier at home! - MG

Not seen that one before. Thanks for posting. - MG

Very interesting and it does explain some of the recent rumours. With W&PR and now Headcorn being run by events companies I think we'll be off to the Hop Farm then. - MG