Hello everyone-
I picked up a used dishwasher in non-working condition, it's a portable 18" wide Kenmore which I believe is a rebadged Frigidaire model. The Kenmore model number is 587.17252200; as far as I can tell this is identical to the Frigidaire model FDS251RJR0. The reason why I know this is that the Frigidaire service manual is available for download from their web site:
http://www.frigidaire.com/tip/s...shwashers/5995371183.pdf and the FDS251RJR0 is identical in every way to mine, including the service documentation sheet that I found tucked inside the front panel...
I am going to use the same terms from the service literature to describe the parts:
"pump housing" - the lower part of the pump; a round piece of nylon that lays in the bottom of the tub, to which the motor itself is mounted. The motor bolts to the underside of the pump housing, and the motor shaft comes upward through a hole in the middle.
Here is a picture of the pump housing, while it is still installed in the bottom of the dishwasher tub; the white flecks are bits of dried dishwasher soap from the previous owner:
"volute cover" - the top half of the pump housing; it's another piece of nylon that is mounted on top of the lower pump housing.
"lower impeller" - fits between the bottom and top pump halves (slides over the motor shaft) and does the actual pumping.
"motor shaft" - the plastic shaft which comes out of the motor and which passes through the pump housing; the lower impeller is pressed onto this shaft.
"shaft seal" - the seal which plugs the hole in the middle of the lower pump housing, and through which the motor shaft passes. It comes in two halves, a lower part which is rubber/ceramic (and which plugs the hole), and an upper part which is rubber/carbon and presses over the motor shaft.
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After I picked up the dishwasher, the first thing I did was to inspect it (without turning anything on!) and I discovered that the motor was stuck and the shaft couldn't turn. I removed everything that was on top of the shaft and pump (spray arm, etc) until I was left with just the pump housing itself as described above. When I removed the volute cover (upper pump housing), I found that the impeller was actually stuck/fused to it. So that was the immediate explanation for why the shaft wasn't turning. I pulled these two parts off the motor shaft stuck together as a single piece, and then the motor shaft turned freely.
With the frozen impeller/volute cover out of the way, I tested the unit with power applied and the door interlock switch disabled. As far as I could tell it operated correctly, the timer went through the correct cycles, etc. The motor turned in both directions as expected for this type of dishwasher (one direction runs the wash cycle and the other way is the drain cycle).
Without thinking about this more carefully, I bought a replacement lower impeller and volute cover, only to discover that the new parts didn't fit right.
The lower impeller presses over the plastic motor shaft; the shaft has a keyway that holds the impeller (and other rotating parts) in place. The keyway ends at a point above the bottom of the tub (although the shaft obviously continues all the way back into the motor).
The impeller therefore can slide down the shaft until it stops at the end of this keyway. But on my dishwasher, after pushing the impeller down as much as it will go, it still sticks up too far and the volute cover (upper pump cover) cannot fit over it without interference.
I also noticed that the top half of the motor shaft seal seems to not be pressed down all the way: according to the service literature, both halves of the seal should be touching but there is a small gap between the top half of the seal and the bottom half. The lower half of the seal is in the right place (in the bottom of the pump housing), as far as I can tell.
The motor seems to be mounted correctly to the lower pump housing, so I think what must have happened was that the plastic shaft (which is obviously attached to the metal guts of the motor somehow) got pulled outward. Is anyone here familiar with how these motors are put together and how I can put the plastic shaft back into position? Does the shaft just press into the motor? I haven't tried forcing it because I don't want it to break.
Could this have been a manufacturing defect, or is it possible for the plastic shaft to shift position by coming unglued, or if something jams against the impeller, etc?
The old impeller must have been grinding against the old volute cover (upper pump housing) for some time, since the two pieces dug into each other and eventually stuck together. I was able to pry them apart with a bit of force, and I confirmed that the new parts I bought were identical to the old ones.
The shaft seal seems okay; I didn't try to remove it because I didn't want to cause a leak (and a new seal would cost $25-$30). Assuming that I can get the plastic motor shaft into place should the existing seal be good to go, or is this part going to be suspect?
Thanks a lot for any advice!
