Dear Ole Mechanic;

I restored an old agricultural pressure pump that was once used to spray an orchard.  The pump was purchased in the late 1940’s or early 1950’s and was last used in the late 1960’s .  I powered it with an old ‘Hit and Miss’ 1 horsepower engine from the 1930’s.  The pump was driven by a flat belt between the pump and the engine.  My initial resetting of the ‘leathers’ on the pumping pistons resulted in leakage around the pumping pistons.

My problem started when I tightened up the ‘leathers’ to cut down on the leakage.  The engine would drive the pump for 1 to 3 minutes, and then the pump would stop turning, causing the belt to slip and then slide off of the pulleys.  I double checked my belt tension and alignment and they are OK.  I even tried belt dressing, but that didn’t help.  I did have the rig running--but leaking--in the Gillespie County Fair Parade and the Harper Pioneers Parade last year and at the Tractor and Engine Show this year before I tightened the ‘leathers’.  Now all the belt wants to do is slip off when the pump stops.  How can I keep this from happening?Witte Engine

Antique Power Nut 

Dear Power Nut;

I saw your orchard spray rig in the Fair parade and at the Tractor and Engine Show.  I remember thinking that the pump was a bit large for the 1  horsepower engine.  Are you sure that is what powered it when it was working in the orchard?

There is something that you can try, but it would take a fair amount of revamping of your trailer set up.  To transmit more power and help eliminate belt slip, the belt would need to be twisted one half of a turn and then installed on the pulleys.  The twist in the belt causes more belt to be in contact with both the driven and the drive pulleys.  More contact means more power will be transmitted before the belt slips.  The draw back to the twisted belt is that the driven pulley will now turn in the opposite direction.  That means that the pump will need to changed so that it will turn in the correct rotation.  Also, you had a very short belt hookup, so you may need to move the pump further away from the engine.

Dear Readers;

I got in touch with Antique Power Nut and found out that the pump was originally driven by the PTO (Power-Take-Off) shaft from an N series Ford tractor which was pulling the trailer that the pump rig was mounted on.  The Ford had 20 horsepower.  I told him that the four-inch wide flat belt might not be able to transmit enough power to drive the pump.  Also, I didn’t think that the 1 horsepower engine was big enough to be able to drive the pump, as it would take some five to eight horsepower to drive it. In addition, a restriction was found in the outlet of the pump that didn’t help things.  The pump is now being set up to be powered by one of the Ford tractors that he has.

Herr Professor Nuzanbolts