I am fairly new to the fresenius machines compared to most of you out there. I am starting to replace brushes in my deaeration motors. Can you give me some tips on how to keep the brushes spread so that you can slip the end piece back on the motor shaft? It's been kind of a pain in the you know what to do it for me. Thanks.

with the end cap off place your new brushes in and put the spring barely on the brush above the grove then carefully put the cap on and with a paper clip with a bend you can slide it in there and push the brush in completely. it will snap into place. it does take practice just hang in there.

You probably have the newer motors that have the white ceramic brush plate and the hair spring in them as opposed to the older one (pre 1997?) with the clock work spring and the brown composition board plate. Just push the brush back into the holder, and pull the hair spring up onto the brass brush holder (there is about an eighth inch end above the groove for the wire) with a pair of short needle nose pliers. Put your finger in front of the brush so that if you let it go by mistake or it dislodges it does not unwind itself. The spring will stay lodged there if you handle the assembly gently. Tuck the brush wire carefully so that it helps hold the brush back in the holder, but make sure that as the brush advances due to wear that the wire will allow it to move forward. That is important particullarly on flow motors as they seem to get hung up frequently. Install the brushes with the wire in the same position as the Dunkermotern, does that translate to Done For Motor? factory does, i.e. on flow motors with the wire towards the bottom of the soft brush, and on hard deair brushes with the groove towards the spring and the wire towards the terminals. If you do not, the wire may eventually get caught in the spring, and the brush will stick and cause the motor to stall out. Install the end cap in the motor and put the Torx head bolts back in one turn only. Lift the whole end cap back out of the motor so that you have a 1/4 inch gap, and you can then see the springs and the ends of the brushes. Take a very small screw driver, or a paper clip and push the springs into place in the grooves on the holder and the grooves in the ends of the brushes. Sometimes it may take two pushes to get the spring in the groove on the brush. If you have the older motor, then you will have to lodge the U shaped end of the spring into the groove on the deair brush by pulling the brush back farther, and you may have more trouble getting it to move into place when you try to seat the brushes. The spring will lodge against the side of the flow brush with no problem. On the deair motor, a paper clip with a small 1/16 inch right angle bend in the end or a dental pick will allow you to pull the clockwork spring away from the groove and seat the spring on the end of the brush. On the flow motor you can just push the brush into place to seat it. A small flashlight or penlight will help you see the brush and the spring, until you get used to the locations of them over time.

Thanks guys I will try your method. I'm sure I will get a lot of practice. K-TECH isn't amazing how a simple process that could be shown in a minute takes an essay to describe. Hence the phrase "a picture is worth a 1000 words"

Hey dude,

This does take a little practice to master, but everyone has their own way that works for them. So, I'll tell you what I do to see if it might work better. Nothing wrong with the way everyone else does it, but it'll give you a few more options to choose from.

What I do is just install the new brushes just like they should be with the springs in place (pushing the brushes in). I'll make sure the wires are positioned in a fashion that will not hinder brush movement as the brushes wear down (i.e. so the brush wires don't get caught on anything). At this point, the brushes will actually be overlapping the hole that the motor shaft goes through. Now, I just install the end cap back onto the motor by putting it on at an angle, pushing one brush back with a small screw driver until it will drop down over the contacts, then pushing the other in so it's over the contacts. Wiggle the cap a bit and it all drops into place. Then just line up the marks you made on the motor housing and end cap and screw it all back together.

Additionally, while you have it apart, I would highly recommend squirting a bit of WD-40 (or similar lubricant) on the motor bearings. Overtime, the carbon dust can get packed in the bearings and cause them to sieze up. If you keep them lubed when you change the brushes, you can significantly extend the life of the motor.


Like you said, a picture is worth a thousand words. Maybe I should do a "how-to" video on this procedure for the noobs.

Village

If you make a video I would like to link it to the BMET wiki.
http://bmet.wikia.com