Speedometer Adapter

Bob Moseley (RIP) · #1 17-09-11, 01:06

Hi all - I am currently restoring an instrument cluster that belongs to a 1943/44 Ford truck with a split differential. To make allowances for the speedometer it is fitted with one of these adaptors, or whatever they are called. My client wants to know where the cable goes from the adaptor to allow it to be operated. A diagram would be nice.

Bob

Lynn Eades · #2 17-09-11, 10:01

I have no personal knowledge, but it will connect somehow to the high / low lever or selector shaft of the transfer case

hrpearce · #3 17-09-11, 11:22

Bob what does the other end of the cable look like and how long is it. We had a 48 Bedford with a vacuum 2 speed but I was only 8 when I drove it and I'm trying to remember how it was set up.

Bob Moseley (RIP) · #4 17-09-11, 12:45

Hi Robert - the cable, if it hasn't been cut is about 18" to 2ft long. The other end is just the interior wire poking out. I would say the cable would connect to the split differential actuating lever so that when the differing ratios were selected the lever on the adaptor would change position thereby speeding up or slowing down the speedometer. But what route does the cble take and are there other brackets?

Bob

hrpearce · #5 17-09-11, 13:29

I'm not much help as I have only driven Bedfords but 18" to 24" sounds right for a conection under the dash. I do remember the Hi /Low in the Bedford was like a choke cable on the dash which made it fun to change box and diff at the same time. the switch tap for the vacuum was on the firewall under the bonnet and connected to the manifold. Nob out connected vacuum and pulled the diff into high, nob in no vacuum and a spring engaged low, so you were stuck in low if anything went wrong with the vacuum. Unfortunately I carn't remember what was under the dash.

John Mackie · #6 18-09-11, 13:57

Trucks with 2 speed rear axles used these adaptors. when they had an electric shift an electric soleniod was incorperated in the adapter. earlier trucks used vacuun shift and had a small vacuum diaphragm mounted on the unit. earlier still the axle was shifted by rods and cables to a lever . that came up through the floor beside the gearbox. the cable concirned would have run from the back of the spedo under the floor to the shift lever.

Also Ausie made Ford trucks with vacuum shifted 2 speed axles had the handbrake moved to the rear wheels as vacuum shifted axles were known to neutralise when parked as the vacuum leaked away.

John

hrpearce · #7 18-09-11, 22:44

Quote:

Originally Posted by John 4172

as vacuum shifted axles were known to neutralise when parked as the vacuum leaked away.

John

Hense Dad's rule of always park in low range.