KSM90PSAC0 KitchenAid Mixer - Instructions

Watch U Tube video. Take care to keep track of disassembly. Hard part was to have 4 types of screw drivers to fit the different screw heads. Be sure to clean broken gear clogs out of the grease. Parts select lady was a great help. Download Parts select diagram for extra help. Time and patience!

I watched a video on how to replace the worm gear. When I opened the mixer I noticed a small screw laying in the grease. I removed as much grease as I could and could not find anywhere that the screw would have come from. All the gears turned and looked fine so I replaced the grease put the mixer back together and it worked fine. I am thinking the small screw must have somehow fallen into the mixer when manufactured. So proud of my 70 year old self for getting the job done.

I did exactly what the PartSelect video demonstrated after watching other DIY videos on the Internet, thus I did not remove the stand which seemed like a little too much for a simple straight forward repair. This is the second time I have replaced this gear. The first time was about 10 years ago when the bakelite gear broke on a 30 year old KitchenAid K
-45. That mixer made hundreds of loaves of bread after grinding many pounds of wheat berries. The only reason we had to replace it was that it walked off the flour dusted counter and landed on its head when my wife had her back turned. Otherwise we would still be using it. :-)
Thanks for the excellent service and instructions.

Dismantled the mixer, took photos, and re-assembled unit.

Went to partselect, found model number, printed blow-up of mixer. Figured out disassenbly procedure. Drove out main pin removing mixer head from stand. Save pin. Drove out pin in mixer main shaft which allowed planetary head to be removed. Save pin.
Removed stainless steel bezel to expose screws for removal of bottom half of mixer body. Removed screws and carefully separated mixer halves using two screwdrivers as prybars. Care must be exercised to prevent chipping of paint on body.
Separated body. cleaned grease from gears to find actual problem. Removed broken geartooth and grease near broken part to make sure no small broken chips remained. Removed pinion shaft assembly, drove pin from gear releasing broken pinion/shaft. Save pin/
Cleaned grease from pinion shaft assembly using mineral spirits and a small brush to reveal how part could be disassembled. Ordered part immediately on-line. Part arrived 1 business day after it was ordered.
Reversed process for replacing pinion shaft. Applied fresh grease obtained from excess already in mixer, spun pinion shaft to make sure grease was properly distributed. Reinstalled pinion shaft assembly. CAREFULLY plugged in mixer and jogged motor to make sure all was free and that mixer worked. If you can repair this mixer, you should have enough sense to do this diagonistic. Keep fingers away from all moving parts, don't touch expposed electric wires. Plug in only after making sure switch is in off position. Jog using mixer switch. Make sure mechanism is free.
Complete re-assembly by following blow-up and reversing disassembly steps. It may be good to write down you disassemblly procedure if it is possible that you won't be reassembling within a day or two.

The shield works sufficiently. Note that the shield is not a continuous circle as shown in the picture. This actually can be an asset because it can be installed or disassembled without stopping the mixer of having to lift the head while running.

The brushes are located on each side of the tilt head of the mixer. I used a screwdriver to remove the screws, removed the brushes & replaced with the new ones. Runs great again!!

Removed back cover, disconnected the 2 push-on connectors, removed ground wire screw. Reversed the process to install new cord.

I had a sourdough batch get into the space where dough hook attaches and it got so stuck that nothing - not hot water baths, not pliers and screwdrivers got the dough hook released. I had to open up the mixer following partselect you tube instructions and replacing the parts. What was confusing to me at first is that my 45 year old mixer had an extra screw on top of the shaft that no longer is there for newer models. It took me longer than I am willing to admit to figure that the extra screw is not the result of me skimming the instructions - the original shaft and dough hook went to a friend who broke it attempting to disengage the two parts (the dough turned out to be a very strong form of glue!). The piece is working like new. I preferred the agitator shaft with a spring to hold the end piece tighter, but the new set up without a spring works just fine.

I replaced the phase control board because the mixer had only
one speed and was surging. I noticed from other posts that it
is important to note the setting of the speed plate before you
remove it in order to remove the phase control board. Also be
careful removing the associated 'slip-on' terminals as it would
be easy to damage the speed plate. If I ever do this again I
will go ahead and replace the speed plate, probably the cheapest
item to replace. The operation was a success and the mixer is
back in business. Thanks.

Removed three screws and lifted out old part. replaced with new part

The new part was too large for the replacement job, but we used the self tapping screws that came with the mixer and screwed them in from the bottom to open the holes a little more since the original screws were to short to hold the new plate. Then we replaced the screws with longer screws and that seemed to do the trick!

I watched a short video on replacing the worm gear, although I did not know what the problem was until I watched the video. after the video ended I took the mixer apart and found the problem located a parts number an placed my order. got the part in one week put in the new part in about 20 minutes and it work like new. and the price was very reasonable

Removed old one and replaced with new one.

Simple fix actually. UNPLUG mixer and remove the one screw on top that holds on the back. The Phase control board sits under and behind the paper insulator and "switch" assy. Remove the 4 wires with a pair of needle nose pliers, the one screw holding it to the back of the mixer and install the new one in reverse order.