How to swap the bearings in a Leybold Turbovac 150 turbo pump

The bearings went out on our reactor turbo pump. It started making a loud whine. A rebuilt Leybold 150 costs like $4000, so swapping them out myself seemed like the only real option. Here’s how it went:

Step 1: Remove the heatsink and housing. Use a metric allen wrench to remove the housing. It’s got a rubber o-ring holding it on, so wiggle back and forth until it comes off. The one I’ve got is missing the heatsink, but from what I can tell you might not even need to remove it.

Step 2: Remove the rings and stators (fixed fin-like things) between each fan. I chose to flip them over and reassemble them. This is really tedious. Check each stator and fin along the way to ensure things are not bent or chipped. I heard that a broken stator can be omitted and the vacuum will still run fine, but at a slightly higher pressure.

Step 3: Remove the fan . Take a clean cloth and wrap it around the fan blades. Hold on tight and use a long allen wrench to break free the bolt in the center of the rotor. Feels weird, but works fine.

Step 4: Remove the washer under the bolt. Use the bolt on the side of the pump to press off the top rotor washer.

Step 5: Pull (i.e. press off) the fan. For this step, I had to machine a custom-fit plastic piece that slots into the notch inside the fan that you can see in the image above. I think a piece of wood with some wedges that “locked” it into place could also work. The goal here is to use it to break free the fan rotor by turning a bolt that sits on top of the rotor. The bolt should be of a small enough diameter to clear the fan and just engage the center rotor.

Step 6: Remove the cover. It’s 3 bolts.

Step 7: Remove the motor shaft.

Step 8: Remove the bearings with a bearing puller. Didn’t get photos of this.

Step 9: Use a lathe or drill press to press the new bearings on. You can get the bearings from Alpine Bearings for $150 each. Put the motor shaft into the tailstock chuck and then press it down through the headstock spindle. Be careful to press only on the inner race.

Step 10: Reassemble. Enjoy!

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