MDB7749SAM1 Maytag Dishwasher - Instructions

Pulled everything out the front, and dug down to find a thrashed chopper assembly (like a little garbage disposal). The previous owner just tossed anything in; pop tops, plastic cutlery, etc.
Didn't pay attention to the exact installation of the chopper as I pulled it out, but, it turns out that it only goes in one way.
Used pictures and instructions I found online as a guide and didn't have any issues.
Replaced the check valve because it isn't expensive and I was in the neighborhood.

followed video instruction

1) Remove the racks

2) Unattach the feed tube the runs from the bottom of the dishwasher tub along the back to the top (this is the grey plastic tube that the top rack sprayer plugs into). This is done by unclipping the tube in two places, one stainless clip is in the back of the tub and one stainless clip is on the top of the tub.

3) After the tube is loosened from the clips, give the tube a 45° twist clockwise (relative to the bottom of the tub) and then pull up. This should remove the entire feed tube and bottom sprayer assembly.

4) There are now 4 stainless steel torx screws visible on the bottom of the tube. Remove the screws using a torx driver. Remove the grey plastic "gear looking" piece that was held in by the screws by pulling straight up.

5) On the left hand side of the tub you will see one more (smaller) torx screw. Remove this screw and then with a pair of plyers, give the housing piece that was held on with the screw a tug straight upwards. There is a post sticking straight up that will help you do this.

6) The grinder assembly is now visible, and in my case, completely jammed with paper. Pull the grinder and screen out of the groove it is sitting in.

7) Place the new grinding and screen into the groove. The grinder blade will have to be pull back (toward you) so the grinder coupling teeth can properly engage with the motor coupling teeth. This may take some fiddling.

8) once the grinder is installed, reverse all the steps starting at step 5.

Very easy to repair with the replacement wheel assembly. Popped out the broken one, popped in the new one. Price was nothing compared to having an professional repair person come to the home. Glad I found you on line!

Cut power and turn off water. Pulled the dishwasher out of the cabinet. Removed internal spray unit. Lay a plastic bag on bottom of tub in case a screw falls from upper spray assembly while removing. Disconnected and drained all hoses. Put down plastic lined tarp on floor. Lay dishwaser on its side onto tarp. Removed hose from recirculation pump, removed water sensor and recirculation pump from housing and detach electric connection. Removed 3 plastic push clips and removed entire motor-pump unit from tub. Position new motor-pump unit into tub. Replace 2 push clips into position, then used a flat screwdriver to put some tension and position plastic pump assembly so I could insert 3rd push clip into position. Replaced all components & reconnect hoses. Turn on water & power. A relatively simple repair. Too bad the original motor-pump only lasted 3 years. Not built like the used to. Thank goodness for Part Select.com Great schematics and descriptions. Excellent website, service, delivery and excellent Part! Thank You!

Disconnect the water supply, the drain line, and the two screws that go up into the cabinet frame, then pull the dishwasher out from under the counter. Tip the unit onto it's face and the main pump/motor is facing up. Turn off the power then unplug the electrical connector from the motor. Remove the single bolt at the base of the motor then turn the whole motor ~1/4 turn counter-clockwise. A firm pull will remove the motor/pump at this point.
The new motor/pump has a new seal. See that the arrows on the pump volute and the motor frame are lined up before inserting into the housing. The new motor/pump slides into the housing easily and a 1/4 turn clockwise will pull it in tight. Re-install the locking bolt and revers the rest of the steps to get running again.

I looked up the most common problem with this model and it was the chopper assembly. I removed everything down to this. Sure enough, mine was broken off and the screen was completely clogged with debris. It was not difficult to replace, but it did take me a few minutes to slide it in to place. Ladies, you can do this. No need to call a repairman! Look up the repair manual and see where the assembly is. I had no idea it was even there. My dishes are spotless now.

.The easiest way to complete the impeller and chopper motor replacement is to disconnect the power, water and drain line, remove the dishwasher from the cabinet, set the washer on its back.

From this point everything is visible, pump housing, motor, etc. and it's a matter of disassembly and reassembly. Make note or a drawing of where all the wires are connected so you reconnect them in the right spots.

Reinstall water lines and power and check for leaks before replacing shield or kick plate.

removed old gasket, installed new.
No Leaks!!
Saved the cost of a new dishwashers

Discovered through internet that it may be a bad chek-valve, Opened washer up and removed inside covers. Actually found that the chopper assembly was bent and non-functional. Ordered new assembly plus ordered a new check valve since the other was 8 years old. replaced both at the same time. Dushwasher works like new once again.

R Draper

it was really easy i removed the lower spray arm then
i removed the four hex head screws that hold on the
fine mesh screen then i pulled out the plastic insert
which exposed the cover to the chopper assembly
removed a smallhex head screw pulled off thecover
and there was the chopper and checkvalve replaced
both with a new one and the dishwasher works like
new thanks a lot im sure a service call would have cost over a hundred dollars

If your chopper assembly has a catastrophic failure like mine did, chances are it took out the teeth on the circulation motor as well. This will lead to the teeth on the chopper being destroyed by the impeller as soon as you turn the dishwasher back on. First, follow the instructional video to remove the motor (found on this site on the circulation motor page) and chopper assembly (also found on this site on the chopper assembly page). The impeller is screwed onto the input shaft of the motor, and you must keep it from turning so that you can unscrew the impeller assembly. I removed the back cover of the motor (there are four screws holding it on) and held a flat pry bar on the rotating assembly inside the motor to keep it from turning, then unscrewed the impeller from the shaft. Mine came off very easy, but be careful not to let your pry bar slip or damage the motors internals. After that, install the washer and grommet from the impeller seal kit on to the impeller, and screw it back on while keeping the motor from turning with your pry bar. Lastly, reinstall the motor and chopper assembly per the aforementioned instructional videos. The whole thing took around an hour to do, and it is much cheaper than replacing the entire circulation motor.

I followed the YouTube video exactly and it went very well

If your not getting clean dishes this is an easy check to make that will likely turn out to be your problem. If not, you need to get this far anyway and it's an easy check to make. Remove the top and bottom rack. The bottom and top sprayer are connected together as an assembly by the water transfer pipe the goes up the back side of the dishwasher interior. This needs to be removed. There are two clips that hold the assembly in place at the middle rear of the washer and the top of the washer. Grasp the water assembly with your hand at the location of the clips, top one first and give a twist that rotates the piece out of the clip. Once the assembly is free from both clips hold the assembly at the lower rear where it starts up the back of the washer and move the whole thing to your right to turn the base clockwise. The whole thing will release from the bottom of the washer and come out as one big piece. Set it aside and you will see four torx head screws that were hidden under it. Remove these screws and the round screen assembly that they are holding to the bottom of the washer. Set that part aside as well. Now your looking at the well area where water collects to get into the pump. There will be a little standing water there, it's normal and not a problem. To the left side of the well an inch or two under water you will see one Torx head screw. It's one bit size smaller than the other screws. Remove it and pull up on the cover that it is holding in place. Now you are looking at the chopper assembly, it's a four bladed knife that rotates across the face of a screen. If you can rotate the knife blades and not have the shaft behind the screen move, it bad! Grasp it by the top of the screen and lift it slightly and pull it toward you to remove it. The shaft that turns the blades has worn away where it connects to the blades. It doesn't turn anymore so the screen is plugging and no water is able to get to your dishes. Order a new one and put it back in the same order you took it apart. It helps to have a little screw driver to lift the knife blade away from the screen when your putting in your new part. Load up the washer and give it a test run. YOU DID IT!!!

FIRST I TURNED OFF THE POWER GOING TO THE MACHINE!!!! Then I removed the top rack by removing the (2) end caps on the front of the rack glides first then lifting the rack upwards and out. Next I removed the bottom rack which slid out easily. I then removed the lower spray arm that was held in place by the plastic turn-screw portion of the lower spray arm support/hub. I turned the screw a few times and the spray arm was released. I then released the feed tube assembly that was held in place by (2) clips; one clip was on the back panel of the tub (above the probe area) and the other clip was on the top panel of the tub (before the upper arm spray). Then I turned the entire tube feed assembly a quarter turn to the right so that it was possible to separate/unsnap it from the feed cap on the bottom. After the feed tube was moved away I was able to access all (4) screws that holds the accumulator in place. I used an allen wrench to remove those. After the accumulator was removed I saw two screws that was holding the 2-part protective cover of the chopper assembly. The small cover came out easily, the round cover took a little jiggling and fussing until I figured out how to pop it out. The chopper was revealed when the cover came off and I found it to be very warn and a bit bent. I pulled it out by pulling it upwards and forward towards me. At this time I also removed the valve check. To my surprise it didn't look like the one that I bougth to replace it. It was missing the round disk portion. I fished around thinking it may have somehow fallen off, but I didn't find anything. I put the new one in, disk-side down. I then put the chopper assembly in place and put everything back together again. I'm not 100% sure that it is completely back to normal. It seems to leave significantly less debris than before, but I noticed that there is more water on the bottom of the basin now. So it may not have been my only problem. If anyone has experienced the same thing I would really like to know