Diagnosis
The "wobbling" effect occurs when the dirty water tank fails to engage the locking lugs on the main chassis. This is typically caused by one of three things: a buildup of dried cleaning solution/debris in the docking tracks, a misaligned gasket preventing the tank from seating fully, or a cracked locking tab on the tank itself. If the tank doesn't "click," the vacuum will often trigger a "Dirty Tank Full" error or fail to create the necessary suction seal, causing the machine to lose power or leak.
How to Fix It
- Clear the Interface: Remove both tanks and use a damp microfiber cloth to wipe the docking area on the machine body. Look for dried soap residue or hair clumps that may be preventing the tank from sitting flush.
- Inspect the Gasket: Check the rubber seal at the bottom of the dirty tank. If it is pinched, twisted, or displaced, the tank will bounce back up rather than locking in. Ensure it is seated flat.
- Verify Tab Integrity: Examine the plastic locking tabs on the sides of the dirty tank. Ensure they aren't bent inward or obstructed.
- The "Firm Press" Technique: Align the tank carefully. Instead of sliding it in, place it vertically and apply firm, simultaneous downward pressure on both the left and right sides of the tank until you hear a distinct audible click.
If That Didn't Work
If the tank still wobbles after cleaning, the internal plastic locking mechanism is likely sheared or warped. Check for hairline fractures on the tank's side lugs. Because this is a mechanical failure of the plastic, it cannot be repaired with adhesive; you will need to purchase a replacement dirty water tank specific to the 1785A model.
Heads Up
Never force the tank into place with excessive violence if it isn't clicking. Doing so can snap the locking pins on the main chassis, which is a much more expensive repair than simply replacing a plastic tank.