Refer to video below. 
You will need two box wrenches (9/16" and a 5/8"). 
Or at least one box wrench (9/16") and one adjustable crescent wrench. 
Tighten firmly but do not over tighten. 
Please refer to the video below.
 
 
 
 
 
 
 
 
There are many different ways to build the Sneaker Dolly. But here's one common situation you may find yourself in. If you're in Pneumatic mode and need to go to a lower mode very quickly on set. Here are two fast conversions you can do in around 1 min 30 secs each. No tools or extra parts required. 
 
 
 
 
 
 
 
 
How To Remove Wheel From Housing
 
 
Sneaker dolly
 
 
​H​andheld  Mobility  System
 
 
Quick Conversion from Pneumatic to Low Modes
 
 
 
 
How to Remove or Replace Entire Wheel Housing
 
 
Please refer to the video below. 
Step 1 - Use a thick flathead screwdriver or flat metal handle from a crescent or similar wrench. Insert the tool UNDER the wheel in the housing and PUSH UP. The wheel will pop up and slide out of the housing. 

Step 2 - There are 4 parts in here. 1 wheel, 1 silver wheel shaft and 2 small spacers. The spacers are basically washers but a very precise width. Careful not to lose these as they're important for the functionality of the wheel. 

Step 3 - Clean the wheel as necessary, then re-install. The only tricky part here is lining up the two spacers as you slide the wheel shaft back in the housing. The spacers should "seat" into the shaft on each side. Sometimes it takes a little fidgeting and as you push the wheel back down the shaft keep in mind that very little force should be applied. It should slide down smoothly. Only at the bottom apply some force to feel the wheel SNAP back into it's seat. And you're done.