Tweet
As a Hammond/Leslie tech, I regularly rebuild the two-speed motor assemblies (motor stacks) in Leslie cabinets. I'm posting about it here because I'm finding more and more that these motors aren't brought in for service until it's too late to save them. By the time they are noticeably noisy or failing to work like they should, they are often irreparably damaged, particularly the shafts and bearings of the slow motors. No one is making replacement rotors or bearings for these motors. You can buy a replacement slow motor, but they are $60-$80 apiece.
If you have a Leslie with a two-speed motor assembly from the 60s or 70s that hasn't had maintenance done, it’s a given that the motors need to be serviced. Do yourself a favor and get it done *before* you notice problems; otherwise, it's like driving a car and never changing the oil. You can oil them yourself if you feel up to the task, but some disassembly may be needed to get to the fast motor bearing that faces the slow motor. The bearings should be re-oiled with electric motor oil or turbine oil (two names for the same thing). Never use 3-In-One Multi-Purpose Oil; their oil specifically for electric motor bearings is OK. Zoom Spout turbine oil or Hammond Organ oil (fresh, not a tube that's 40 years old!) works very well.
A proper motor rebuild involves complete disassembly, cleaning, and replacement of any worn parts, and it's not as easy as it might look. (For example, you have to de-burr the fast motor shafts carefully on both sides before they will slip back through the sleeve bearings.) A number of the small hardware parts needed are not (or are no longer) standard sizes and are only available from aftermarket Hammond/Leslie specialty parts suppliers. It can be tricky to do the final shimming and adjustment if you haven't developed a feel for it. If you have any doubts, get your local Leslie tech to do it for you. Virtually all the amateur rebuilds I've seen are incorrectly reassembled in some way. I even ran into one where someone had flipped a motor armature and had the fast and slow motors running in opposite directions...
One insidious failure mode: the springs in the slow motor assemblies gradually eat into the steel washers above and below them, creating a knife-edge on the inner diameter of the washer; this, in turn, cuts a groove into the motor shaft. Eventually, it causes the mechanism to jam or become noisy. Instruction sheets for replacing the springs in slow motor assemblies often state that it’s not necessary to replace these metal washers, and, thus, the typical “motor kits” you find for sale online don’t include them. While this statement may have been true twenty years ago, it’s not true anymore. And, as I said above, the replacement parts must have the correct dimensions.
Bottom line: people ignore Leslie motors and assume that they'll work forever with no maintenance. Not true.
If you have a Leslie with a two-speed motor assembly from the 60s or 70s that hasn't had maintenance done, it’s a given that the motors need to be serviced. Do yourself a favor and get it done *before* you notice problems; otherwise, it's like driving a car and never changing the oil. You can oil them yourself if you feel up to the task, but some disassembly may be needed to get to the fast motor bearing that faces the slow motor. The bearings should be re-oiled with electric motor oil or turbine oil (two names for the same thing). Never use 3-In-One Multi-Purpose Oil; their oil specifically for electric motor bearings is OK. Zoom Spout turbine oil or Hammond Organ oil (fresh, not a tube that's 40 years old!) works very well.
A proper motor rebuild involves complete disassembly, cleaning, and replacement of any worn parts, and it's not as easy as it might look. (For example, you have to de-burr the fast motor shafts carefully on both sides before they will slip back through the sleeve bearings.) A number of the small hardware parts needed are not (or are no longer) standard sizes and are only available from aftermarket Hammond/Leslie specialty parts suppliers. It can be tricky to do the final shimming and adjustment if you haven't developed a feel for it. If you have any doubts, get your local Leslie tech to do it for you. Virtually all the amateur rebuilds I've seen are incorrectly reassembled in some way. I even ran into one where someone had flipped a motor armature and had the fast and slow motors running in opposite directions...
One insidious failure mode: the springs in the slow motor assemblies gradually eat into the steel washers above and below them, creating a knife-edge on the inner diameter of the washer; this, in turn, cuts a groove into the motor shaft. Eventually, it causes the mechanism to jam or become noisy. Instruction sheets for replacing the springs in slow motor assemblies often state that it’s not necessary to replace these metal washers, and, thus, the typical “motor kits” you find for sale online don’t include them. While this statement may have been true twenty years ago, it’s not true anymore. And, as I said above, the replacement parts must have the correct dimensions.
Bottom line: people ignore Leslie motors and assume that they'll work forever with no maintenance. Not true.