I have a sketch and some photos that I have tried unsuccessfully to attach to this post so if you let me have your e-mail address I will try again.

The thermostat for the radiator shutters can be easily repaired if the bellows are still intact. I repaired the bellows on my 1929 633 about 8 years ago and it is still working. There is a small hole that has been soft soldered closed, which if my memory serves me correctly, is on the hexagonal nut. I simply drilled a 1/16" dia hole through this and injected about one teaspoon full of ether into the bellows then soldered the hole closed. However it is only a matter of time before the old bellows suffer fatigue cracks and then it will be beyond repair unless suitable replacement bellows can be found. So, if the above repair includes new bellows then that is the way to go, otherwise it is a temporary fix
I have since made a new shutter thermostat using a modern wax filled thermostat from a large industrial diesel engine for another 1929, this works better than the repaired one which opens prematurely probably due to my having put too much ether in it.

Mal, I look forward to reading all about our rally when my head stops swimming. We just got home in the 1929 Sedan after driving the last 1400 kms in 2 1/2 days. The car performed very well (apart from the split rim) considering it was its very first run after a 10 year restoration. We experienced vaporisation on the last 2 days as the weather warmed a little. My other 2 cars are the same or worse. Every time we stopped I put my ear to the vacuum tank and could hear the fuel boiling. Much as I like to keep them authentic, "warts and all" I think its time to bypass the vacuum tank, which sits over the exhaust manifold, acting like a stove, and fit an electric pump feeding directly to the carburetor. As we can't buy the original higher boiling point fuel then we need to modify the fuel delivery system to suit the stuff available.
It was a great rally.

I bought the bearings from a general bearing supply business where I take all of my old bearings for new replacements, they have been very helpful over the years in finding bearings that either fit or can be adapted. The person who served me commented that it was the same bearing used in the lower end of the king pins on a Nissan Patrol but did not say the year. The part number is not a Nissan part number, its a bearing number which suggests that it does have other applications and is probably available in US using the part number.

I would like to add my two cents worth to Peter's advice regarding new replacement king pin bearings. These comments are based on my 633's which I believe are the same as the 733.
I restored my first 633 using the Volkswagon bearings. I have since restored another 633 and have found what I believe are better bearings.
The top bearing can be replaced by a new bearing identical to the original. The number for the top double row ball bearing is YSB 5304-2RS.
The bottom bearing can be replaced using the lower king pin bearing from a Nissan Patrol 4WD, Its a Koyo Hi-Cap bearing number 3030 4A JRRS with seal. the advantage of this bearing is that it has a much higher load capacity and most importantly it incorporates a thrust face seal eliminating water ingress that can be a problem.
When grinding back the radius for the balls on the original king pin it will be necessary to measure the new bearing and lower housing to ensure some compression of the new seal. Also the lower bearing housing has 2 holes to allow a pin punch to be used to remove the bearing. These holes should be blocked with say Silastic to prevent entry of dirt and water into the new bearing which is open on the bottom.
I would have attached a sketch but failed after many unsuccessful attempts.
David Australia

That is a very nice looking 126 Sport, mine is the one in the photo posted by Ozstatman. Its been on the road since 1985 and we have toured extensively with, it will need a third set of tyres soon. The Sports have a slightly taller diff ratio and they will cruise at about 50 mph max once fully warmed up. The one you are looking at looks very correct, the disc wheels were unique to the Sport in 1922 although for reasons unknown all 126 open cars that I have seen in Australia had Rudge Whitworth wire wheels like mine. the colour looks correct also. The Sports are fairly rare but I would not know how much its worth, unfortunately this era does not attract a lot of interest. Don't worry about the 2 wheel brakes, if you drive it within its limits they are fine (except in heavy rain) If you like it and can agree a price, buy it. I have never seen a better unrestored one.

That theory about excessive speed of water through the radiator is a myth even though it comes up often. The speed of coolant through a heat exchanger or the source of the heat does not effect of the efficiency of cooling (within some very wide bands). However what can happen is removal of the thermostat can reduce the resistance of the water flow from the pump which may can cause the pump to cavitate preventing the water from flowing.
The thermostat is there to speed up the warm up time of the motor and to maintain a constant water temperature particularly in cooler weather.
If the car is over heating its not the thermostat unless of course it has jammed closed.

Peter, the bonnet hinge length on both of my 6th Series cars (633) is 38 1/4" and about the same distance from firewall to radiator. Both cars have front mounted water pumps.
I guess you are wondering whether the earlier 6th Series cars used side pumps and the same length bonnet and engine bay as your 5th series.
I don't know but I just checked the parts book and it lists only one part number for the 626/633 bonnet assembly for each body style. (The open car bonnets have the swage line in a different location to the closed cars)
And by way of trivia the Packard parts book calls them "bonnets" not "hoods"!
David McCredie

Glad it came off OK.
I do not know which came first the front mounted or side mounted pumps but I agree that the front mounted is a very poor design caused by having to fit the pump into too little space. Adjusting the gland nut is awkward at best and normal gland leakage drips onto the vibration damper rusting the internals and locking it up.
My cars now have modern sealed bearings and modern ceramic faced seals which are now working fine with zero leakage.

The vibration damper bolts to the face of the fan pulley and is located centrally by a spigot that penetrates the VD by only about 3/16". Remove the hand crank nut then the 4 bolts and it should come off reasonably easily. Be careful not to lever off the fan pully flange where the belt runs as it is likely to be very thin and easy to break.
Incidentally my 2 1929 Standard Eights have front mounted water pumps and have front mounted vibration dampers, in my opinion the drawing in the book is wrong, I have never seen one with the VD behind the fan pulley.
David Australia