[Skripo]

I just got 2 used Iwaki MD70RLTs and took them apart for inspection of the bearings. Once I pulled the front internal magnet off I noticed that the pump ran much smoother. Being a longtime RC helicopter enthusiast has given me an appreciation for balance and proper centering of rotating masses.

You must first remove the full front pump assemby to access the interior magnet. At this point you need to loosen the 2 metric set screws that are at a 90 degree angle to each other, the root cause of our balance problem.

Once loosened, simply pull the unit off the shaft for inspection. You will notice that there are holes drilled in the casing and front face. Do not be concerned with these, they where made to balance the magnet in 2 planes to reduce vibration.

The modification is relatively simple but demands high precision. A good mill with the proper tools will be required to drill 2 .492mm holes on the opposite sides of the set screws. If you do not have one GO TO A MACHINE SHOP. It is less than 1/2 an hours labor!

Once done, tap for and insert 2 more 6 mm set screws. If you can not get the exact same ones put each matching pair in opposite holes. Make sure to use blue Loctite because the vibration will loosen them over time!

Now remount the magnet on the shaft and tighten the opposing pairs of screws until they just start to tighten.

Check the runout (the amount that the magnet runs off center) by holding a small pin close to the magnet and observing the space.

Bring the magnet to the narrowest gap with your pin and locate the set screw nearest it and tighten.

Continue adjusting the 4 set screws until you get a perfectly centered magnet.

You will be rewarded with a vibration free, quiet running pump.

My next mod will be replacing the horrendously loud fan on the end.