KitchenAid K400 Blender Leaking Jar Fix – Full Repair Guide (608RS Bearings Replacement) (5KSB4026AHI)
Symptoms
The base of the jar leaks liquid after use.
Background
We bought the K400 to make almond milk daily. We specifically chose this model for its glass jar—we’re not fans of plastic jars in blenders. The high forces generated by the spinning blades transfer directly into whatever you’re blending, and with plastic, there’s always a possibility of microplastic chipping (just my uneducated, unscientific deduction! 😊).
After around six months of daily use, the jar started leaking. At first, I thought the gasket at the base had failed. Nope. The leak was due to worn bearings in the spindle. You can check this easily: hold the bottom of the spindle and move it side-to-side. If there’s noticeable play, the bearings are worn, which causes leaking.
I contacted KitchenAid support. They were very helpful, but unfortunately they no longer supply spare parts—neither complete replacement jars nor spindle/blade assemblies.
How I Fixed It
1. Removing the Base
Taking the base off is simple—just four T20 Torx screws. Once removed, the entire spindle assembly lifts out from the top of the jar.
2. Removing the Spindle / Bearings Assembly
Next, you’ll need to remove the top nut on the spindle. Turn the nut clockwise (yes, clockwise!) to loosen it. This reverse threading is designed so the nut tightens itself during normal operation.
It’s a little tricky: use a spanner or vice-grips to hold the spindle from underneath to stop it spinning.
Then remove:
- the nut
- the top washer
- the blade
- the bottom washer
At this point, you can use a rubber mallet to knock the spindle/bearing assembly downward and out of the plastic housing. There are two rubber seals around the bearings. The top seal usually stays in the housing—just pry it out gently.
3. Removing the Old Bearings
The bearings are a common size—608RS, the same type used in most skateboards. You can get replacements on Amazon or AliExpress. Make sure the replacements have rubber seals on both sides.
Before removing anything, note the exact position of the bearings on the spindle so you can install the new ones in the same place.
If you have a bearings puller, great. It will make the bearings removal job much simpler. If not (like me), do this:
- Heat the bearings using a heat gun.
- At the same time, place the spindle in an ice bath.
The heat expands the bearings; the cold shrinks the shaft. After a short while, you should be able to pull the bearings off with pliers.
4. Installing the New Bearings
This part is easier:
- Heat the new bearings with a heat gun.
- Cool the spindle again in an ice bath.
The heated bearings should slide onto the shaft with moderate pressure.
Important: Don’t forget to install the bottom seal first, otherwise you’ll have to remove the bearings again—and that’s not fun.
5. Re-assembly
Once the new bearings are on:
- Insert the spindle back into the plastic housing.
- Make sure the top seal is already seated in the housing.
- Push the bearings assembly all the way down until the bottom seal sits flush with the housing.
- Reinstall the bottom washer, blade, top washer, and nut.
- Tighten the nut anti-clockwise this time.
- Re-attach the top and bottom plastic housing with the four Torx screws.
- Ensure the orange O-ring is properly seated in its groove.
6. Post-Repair Notes
We’ve been using the repaired jar for three months now, and there has been no leakage at all.
Just one tip: try to keep the bottom of the plastic housing dry when washing the jar. Excess water can accumulate around the bottom seal and water can seep into the bearings and cause it to fail prematurely.
If you attempt this repair yourself, let me know how you go!