Restoration of Hull 731- Carrier, MG (Aust) Mortar Carrying

[Dale Jordan]

Excellent workmanship Darrin . Good timing for me with these photos, I needed that shot of the conduit layout under the nose . Did you use modern new saddles to hold in place ? also notice that your left hand head light guard must be further outboard on your fender then my carrier . Dale

[Darrin Wright]

Dale, I don't believe that you can get these old style thick half saddles anymore.
I have managed to salvage from 4 hulls (project hull included) conduit, fittings and saddles. Using modern steel tubing I have replaced several sections of straight conduit and threaded it myself with a 3/4" UNF die.
The conduit against the centre bulkhead and under the air scoop is 1" dia and due to that being high off the floor has survived very well. The additional diameter is to accommodate the extra wiring for the generator, regulator and to battery.

[Dale Jordan]

Thanks Darrin . Where does the change from 3/4 '' to 1'' take place is it from the tee peace under the instrument panel or at the right angle at the fire wall . also is the 3/4'' and 1'' outside O/D or inside .. Dale

[Keith Webb]

You mean saddles like this one with a carrier part number stamped into it?

[Darrin Wright]

I managed to spend most of Saturday working on the BGC and achieved a fair bit.
Removed that front left wheel and inspected the stub axle. There were several small burs or gouges that were catching the outer bearing. So filed and polished these off and then the wheel slid into place, installed the slotted nut and split pin.
Bought more nuts & bolts for the rear armoured diff cover, painted these and located the rear cover into position. Had to run the electric drill through some of the holes to get the bolts through. Prior to fitting this, it was easier to run the rear wiring loom and install the conduit in position and drill and mount the half saddle that holds the conduit in place. I am using modern wire and running additional earth wires were required.

Fix or adjusted the front conduit so that it sits correctly and ran a new (longer) wire in position as I was not happy with the other wire.

Installed the steering box onto the steering column, had to clean the splines with a file and wire brush and used plenty of lubricant to get them together. I do not fancy trying to separate the 2 items later...

I then installed the drivers floor plate into position to check fit, got carried away with the progress and installed the steering column into position. Still waiting on the 1/2" UNF turn buckles to be machined, but they can be installed later. Will install the mounting bolts for the floor plate this weekend.

Went to install the clutch rod, which I had made previous, and found that it was too long. This item I had made from the measurements in the parts book, minor oversight back then. Will cut down the rod and re-thread.
I also painted several items for installation in the coming weeks.

[Darrin Wright]

I have found the following hub seals used on the BGC:
Front inner (stub axle) TC12193
Front outer and wheel pins TC12152

a common seal normally stocked at most bearing places

[Darrin Wright]

This was a cold but productive weekend, with cold wet weather blowing in for the weekend and the family off on a scout trip gave me about 6 hours on Saturday and 2-3 hours on Sunday.

The drivers floor plate has been bolted in.

The 1/2" rods from the steering column to the steering cam plate are now in. Had trouble with these rods as I had about 10mm too much thread sticking through the long clevis yokes at the steering cam plate. this resulted in the front pointy bits (tech term) hitting on the protruding thread section. Removed this offending thread and the adjustment will be made at the front clevis yokes, that will make adjustment later much easier. The steering wheel now moves the tube axle from side to side, which will warp the tracks. Gravity is not my friend right now, due to the design and position of the tube axle rollers.

Bought a new tap & die set from the local tool shop, this has allowed me to thread my steering linkage rods (before I had a generous friend who cut the threads for me). I have made the linkage rod in front of the gunners feet and installed the clevis yokes and painted it in undercoat. This rod is 28" from pin to pin.
Recovered and primed the special purpose pin for the accelerator linkage in the front of the hull/drivers compartment.
Have attached a pic of the 2 special pins for the clutch and accelerator linkages in the front of the hull. These 2 pins take the return spring. Accelerator pin is 1/4" and the clutch pin is 7/16" dia.

Modified (shortened the rod from the original parts book listed length) and installed the clutch rod and have commenced adjusting the rods to achieve some sort of clutch pedal. Will have to run the engine to complete adjustments. Installed the NOS spring to the pedal.

Installed the RH guard and installed the elec conduit. This has been wired up from the dash to the headlight mount. The guard is not perfect, it still retains some damage from being in service as this is the period (1942 to 43 in Darwin) that I am restoring the vehicle back too.

Finished tightening the mounting bolts for the exhaust system, this is now finished.

My wife came down to check on me, so taught her how to install a road wheel. This was fitted to the RHR suspension station unit and she fitted and tightened the wheel pin nut. I had to jack up the hull and hammer in the pin.
The hull now sits on the ground on its rear wheels with the front of the hull on jack stands.

There are a few items I am yet to turn my attention too, these are the strip down and rebuild of the bogie suspension units and the panel beating of the left front guard. The wheels are all blasted and painted ready. Also have to wire the vehicle up, but still trying to figure out how they installed the wiring conduit through the centre baulkhead, from engine to dash.

[Darrin Wright]

Over time I have slowly been conducting research and trying to find out more info on the modifications to convert a BGC into the 3" Mortar Carrying version.
Months ago I emails the AWM if they had drawings AFV (T)1201, 1202, 1207, 1208 & AFV (SK)740, as these are the working drawings for rear echelon Ordnance Wksps to convert a limited number of BGC to provide for the mounting of a 3" Mortar on the engine cover and stowage of bombs and stores in the rear compartment.

They dug around and provided me with some reference material in the Melb office. Well I finally got around to registering with them and booked the files out for this afternoon.

It was interesting looking through the documents and the archive people were very helpful.

The information was not the holy grail, but it did document some of the history of how the modification came about, also found all the information from Met Gas on the production schedules (A & B) for 2 pdr AT and 3" Mortar Carriers. These schedules listed all the manufactures of the parts (pic attached) that were interchangeable between the vehicles and also listed all the Met Gas produced parts.
A common number of parts produced, as listed in these schedules is 210 for single items and 420 for items two of a kind. This leads me to speculate that they were committed to producing at least 210, 2 pdr or 3"Mortar carriers at that time.
These schedules were printed/written on 22 Sept 42.

back to the 3" Mortar, some condensed notes of my findings:
20 Oct 41, Mr Frank Mead writes a letter to the Army suggesting several modifications that he has come up with, from his service in the great war. One idea is to mount a Mortar or Howitzer onto the back of a BGC.
12 Nov 41, Idea declined by the Inventions Board Eastern Comd as the BGC is too light and would be overloaded.
At this point in time, only the Aust LP1 BGC had been produced and was in limited service.

4 to 18 May 42, TPR J. White writes a letter through his chain of command, ref fitting a 3" mortar to a 2 wheeled trailer to allow for better mobility and use of the mortar. In these letters he/they acknowledge that 3" mortars are fitted to BGC.
5 Jun 42, letter declining the 2 wheeled trailer mortar carrier. The Director of Mechanization states that:
Mortar carriers have been received from overseas,
Local made model now being produced.

4 May 42, another letter states that 3" mortars currently being fitted to BGC.

TPR White was posted to 2nd Aust Armoured Brigade, Rec Sqn, AIF at the time of his letters.

Will post pics soon as internet playing up...?