I had already decided to refit all the gauges in my bus, with Stewart Warner Heavy Duty Plus gauges. I ordered an oil pressure gauge and a oil pressure sender, from a local Stewart Warner distributor.
A friend and I made the trip from Southern California to St. George, Utah. When I arrived at the mechanic, he told me that the bus was located out back. Before I warmed it up, and certainly before we left the yard, I wanted to install the new gauge and sender. Fortunately, I have a copy of the maintenance manual for my bus.
There are three senders on the manifold, and they all look alike. I removed the lead from the sender that was pictured in the manual, and started the engine briefly. If I remove the right lead, there would be no pressure registered on the gauge. As luck would have it, I found the correct lead on the first try. While I was back there, I remove the old sender and replaced it with the new Stewart Warner sender. The two senders looked identical.
Next I had to install the gauge in the dash. After removing the existing gauge, I installed the new gauge. The dimensions were the same, so the new gauge installed very easily. I connected the existing line from the sender. After that, I ran a couple new lines for the power, ground and dash light.
With the dash in place, I fired up the engine again. The needle on the new gauge snapped to life and matched the reading on the mechanical gauge back at the engine. The whole process took about 20 minutes to complete.