how to tighten belts on compressor
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danielbuck
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does the electric motor have slots where it bolts down? If not, probably best to either get a new belt, or get a "link" belt that you can adjust.
If you're feeling fancy you could rig up some sort of "tension pulley" like on a lot of vehicle serpentine belts...
If you're feeling fancy you could rig up some sort of "tension pulley" like on a lot of vehicle serpentine belts...
you also don't want the belt too tight, it's hard on bearings. so just get a surface you can get a pry bar into and put "some" pressure on it. keep it aligned too
signcrafter
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What I usually do is loosen all the bolts for the motor. Then pull the motor to just about the right tension and tighten one bolt that is opposite side from belts and closest to the pump. Then I gently twist the motor just a bit to put some more tension on the belts. This usually works good when working alone. Just don't go crazy and end up with motor at a big angle. Also if you start out with motor angle just a hair when you twist it then it will be straight.
honcho
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The tool to assist you is called a Belt Tension Jack. I have one that I last used years ago on a belt driven stationary AC compressor.
danielbuck
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I use reversible clamps (so they press outwards) to push the electric motor and hold it there while you eyeball the alignment.
And if you want to be **** about it, you can put a straight edge on the pulley to make sure it's inline with the pump pulley. If the pulleys are different widths, put the straight edge on both sides of the electric motor pulley and look where it lines up on the pump pulley. If you can't get a straight edge on the inside of the electric pulley, put the straight edge on the (probably fatter) pump pulley, and look at the the gap at the close and far side of the electric motor pulley. If that makes sense. Tap the electric motor with a hammer till it looks/measures right.
I did that the first time with the straight edge. Probably not needed, so now I just push it with the clamps, eyeball it from the side, tap it (if needed), then tighten the electric motor bolts.
And if you want to be **** about it, you can put a straight edge on the pulley to make sure it's inline with the pump pulley. If the pulleys are different widths, put the straight edge on both sides of the electric motor pulley and look where it lines up on the pump pulley. If you can't get a straight edge on the inside of the electric pulley, put the straight edge on the (probably fatter) pump pulley, and look at the the gap at the close and far side of the electric motor pulley. If that makes sense. Tap the electric motor with a hammer till it looks/measures right.
I did that the first time with the straight edge. Probably not needed, so now I just push it with the clamps, eyeball it from the side, tap it (if needed), then tighten the electric motor bolts.
Last edited:
sberry
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OccupantRJ
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Sberry’s Idea is probably the easiest way for one person to do it with good control. I solved the issue on one of mine by making the modification in this link.
https://www.garagejournal.com/forum/showthread.php?t=404865
https://www.garagejournal.com/forum/showthread.php?t=404865
matt_i
Well-known member
If one is an aspiring machinist with a mill and looking for a project, this is a good project. Take some ~3/8" to 1/2" steel plate and cut a piece that matches the motor's base and drill holes that match the pattern.
Drill and tap the edge of the plate for a tensioning jack-screw. Deep as it can go.
Last part of the puzzle is to build a cross-bar (square stock, could be box tube) which attaches to the compressor and has a thru-hole for the same jack-screw.
Likely have to get longer motor-mounting bolts, by the 3/8 to 1/2" increase. Need a jack-screw which can be a hex or socket head screw.
So you loosen up the motor mounting bolts so the motor can slide, install the belt, add tension via jack screw, tweak until satisfied, then tighten the motor mounting bolts. Probably a good idea to put a jam nut on the jack-screw so it doesn't fall out under vibration, or else pull it out and tape it somewhere.
The slight raise in motor-sheave should not significantly affect the belt length nor interfere with the guarding unless its way out at the limits of travel and in that case it might be time to revisit the belt length once again.
Drill and tap the edge of the plate for a tensioning jack-screw. Deep as it can go.
Last part of the puzzle is to build a cross-bar (square stock, could be box tube) which attaches to the compressor and has a thru-hole for the same jack-screw.
Likely have to get longer motor-mounting bolts, by the 3/8 to 1/2" increase. Need a jack-screw which can be a hex or socket head screw.
So you loosen up the motor mounting bolts so the motor can slide, install the belt, add tension via jack screw, tweak until satisfied, then tighten the motor mounting bolts. Probably a good idea to put a jam nut on the jack-screw so it doesn't fall out under vibration, or else pull it out and tape it somewhere.
The slight raise in motor-sheave should not significantly affect the belt length nor interfere with the guarding unless its way out at the limits of travel and in that case it might be time to revisit the belt length once again.
pepi
Well-known member
Could cut two wedges, insert them in the front slots. With the motor snug, not tight, not loose. Use a ball-peen or brass hammer tap each shim. The shims will keep the motor aligned.
When desired belt tension is reached, tighten the rear mounting bolts. Remove wedges and secure the front bolts.
You want at least a 1/2 inch up and down movement of the belt.
Pep
When desired belt tension is reached, tighten the rear mounting bolts. Remove wedges and secure the front bolts.
You want at least a 1/2 inch up and down movement of the belt.
Pep