Broken Couplers

Equipment breaks! That’s a quick lesson from the school of hard knocks. However vacuum tanks are set up with a variety of protection components to take the sting out of your repair bill. The coupler between your gearbox and vacuum pump is one of these components.

Couplers take the stress every time you engage the PTO to start your vacuum pump. There are multiple styles, but all of them are basically designed to dampen the shock when you start your vacuum pump, lengthening the life of your equipment.
Although it’s mostly out of sight and out of mind, your coupler insert is slowly wearing down. At some point it will need to be replaced. Preventative maintenance is not necessary often, but periodically checking the teeth for wear and the rubber for dry rot or cracking may save you down time in the future.

If you are replacing your coupler, there are two very important concepts that will significantly increase the life of your equipment. The first one is verifying the alignment of the metal coupler housing. Use a straight edge to verify top, bottom, left and right sides of coupler housings are perfectly aligned with each other. If the housings are not perfectly aligned, your rubber coupler insert will quickly wear and fall far short of its intended lifespan.

The other concept to consider is allowing endplay on both ends of the rubber insert. When the insert heats up it will expand significantly and push on your pump rotor. The pressure can force your pump rotor into the pump housing endplate. As mentioned before, every coupler can vary but on a common #9 Sure-Flex coupler you should have approximately 1-7/8” total distance between the steel flanges (smaller for a #8 and larger for a #10). This will allow room for the coupler to expand without putting pressure on your pump rotor. For exact measurements refer to the instructions that come with your new coupler.
Hydraulic motors may use a coupler style that allows metal teeth to interlock. This is acceptable because of the hydraulic relief valves. Direct drive PTO systems should never use this type of coupler. A complete rubber insert should be used allowing the coupler to shear if something in the pump locks up.

Attention to the small details will often pay large dividends. Giving your coupler some attention today will put you ahead of the game and save you costly down time in the future.

Ike Martin -Pik Rite, Inc.
Ike has been servicing and rebuilding vacuum pumps for the past 13 years. His experience and expertise in the service department at Pik Rite, Inc. is highly valued. Pik Rite manufacturers and services commercial vacuum tanks, hoist units, roll-offs, slide-ins, portable toilet service units and tank trailers ranging in size from 300 to 6,500 gallons. Our 15 year steel tank warranty sets us apart from the competition. Tanks are available in steel, stainless steel and aluminum.

Call 800-339-3840 and mention promo code ALW for a 10% discount on pumps and pump parts during the month of February.