What Comes in the Package?
The package contains:
- One K500066 front lower driver-side ball joint
- One K500067 front lower passenger-side ball joint
The two joints are not interchangeable:
| Part number | Position |
|---|---|
| K500066 | Front left lower |
| K500067 | Front right lower |
Compare both replacement joints with the original parts before beginning installation.
Product Specifications
| Specification | Detail |
|---|---|
| Brand | SCITOO |
| Product type | Front lower ball-joint set |
| Quantity | Two pieces |
| Placement | Front lower, left and right |
| Driver-side number | K500066 |
| Passenger-side number | K500067 |
| Construction | Heat-treated steel and rubber components |
| Lubrication | Supplied pre-greased |
| Replacement type | Direct-fit aftermarket |
| Support | Advertised one-year replacement support |
Warranty and replacement coverage should be confirmed with the seller at the time of purchase.
What Does a Lower Ball Joint Do?
The lower ball joint connects the front suspension assembly to the steering knuckle. It lets the wheel move through steering and suspension travel while remaining securely located.
Each joint helps maintain:
- Controlled steering movement
- Suspension articulation
- Wheel position
- Alignment stability
- Predictable handling
- Proper tire contact
The official Lexus parts catalog identifies separate left- and right-side lower ball-joint assemblies for the first-generation IS300.
Symptoms of Bad IS300 Ball Joints
Worn lower ball joints can cause:
- Clunking over bumps
- Popping during turns
- Loose steering
- Steering wander
- Excessive front-end vibration
- Uneven tire wear
- Alignment instability
- Torn dust boots
- Grease leakage
- Excessive movement at the knuckle
SCITOO’s reference to a “crash sound” is better understood as a clunk or knock from the front suspension. If the car sounds like it is actually crashing, the diagnostic process has moved beyond ball joints.
Our guide to diagnosing a clunking noise over bumps explains how worn joints can be confused with bad sway-bar links, control-arm bushings and shock mounts.
Will These Ball Joints Fix Uneven Tire Wear?
They can help when excessive ball-joint movement is allowing the wheel to shift outside its intended geometry. However, uneven tire wear can also be caused by:
- Incorrect toe
- Excessive camber
- Worn control-arm bushings
- Damaged tie rods
- Weak shocks
- Bent suspension parts
- Improper tire pressure
- Wheel or tire damage
Replacing the ball joints without diagnosing the rest of the suspension may leave the original tire-wear problem unchanged.
Read our Energy Suspension buying guide for more information on how deteriorated bushings affect alignment and steering response.
Construction and Durability
SCITOO describes these ball joints as using heat-treated steel and high-grade rubber components intended to resist:
- Normal suspension loads
- Pothole impacts
- Road vibration
- Temperature changes
- Moisture and road contamination
- Everyday driving stress
The joints arrive pre-greased, which means additional lubrication should not be necessary before installation unless the supplied instructions state otherwise.
Inspect each dust boot before installing the part. A pinched, cut or improperly seated boot can allow contaminants into the joint and drastically shorten its service life.
Replace One Side or Both?
Replacing both joints is generally worthwhile when:
- Both parts are original
- Both boots show deterioration
- The vehicle has high mileage
- Play exists on both sides
- A complete suspension refresh is underway
- Labor overlap makes paired replacement practical
The SCITOO kit provides both sides, so there is no need to order K500066 and K500067 separately.
If only one joint has failed and the other passes a proper inspection, replacing one side is possible. The remaining joint should still be monitored because it has experienced similar mileage and age.
Inspect the Rest of the IS300 Suspension
Before blaming the ball joints for every front-end problem, inspect:
- Upper control arms
- Upper ball joints
- Lower control-arm bushings
- Caster-arm bushings
- Inner and outer tie rods
- Sway-bar links
- Stabilizer-bar bushings
- Wheel bearings
- Steering-rack bushings
- Shocks and upper mounts
- Front tires
Our article on why the steering wheel shakes covers common wheel, tire, brake and suspension causes.
If the noise appears mainly during steering, see the guide to clicking noises while turning.
Installation Notes
Ball-joint replacement is an intermediate-to-advanced suspension repair. Typical equipment includes:
- Floor jack
- Properly rated jack stands
- Wheel chocks
- Metric socket set
- Breaker bar
- Torque wrench
- Ball-joint separator
- Pry bar
- Pliers
- Penetrating oil
- New cotter pins where required
Raise the vehicle from the approved lifting points and support it securely. Never work underneath a vehicle held up only by a hydraulic jack. Review our guide on using an automotive jack safely before beginning.
During installation:
- Confirm K500066 is on the driver side.
- Confirm K500067 is on the passenger side.
- Compare the stud, housing and mounting holes with the original joints.
- Protect the brake hoses and ABS wiring.
- Inspect the steering-knuckle mounting surfaces.
- Replace damaged or required locking hardware.
- Torque all fasteners to specification.
- Confirm both dust boots are seated correctly.
Never use a pickle fork against a joint you intend to reuse. It can tear the boot, which converts “reusable” into “newly damaged” with impressive efficiency.
Torque and Alignment
Use a torque wrench and the correct factory specifications. Under-tightened hardware can move during operation, while excessive torque can damage threads or distort mounting surfaces.
Consult the Pro Street Lexus IS300 torque-specification guide and verify applicable values against factory service information for the exact model year.
A professional alignment check is recommended after installation, especially when related lower-arm hardware has been loosened.
The alignment should verify:
- Front toe
- Camber
- Caster
- Steering-wheel position
- Straight-line tracking
Complete all suspension repairs before the alignment. Otherwise, worn components can move after adjustment and invalidate the measurements.
Frequently Asked Questions
What years does the SCITOO kit fit?
It fits the 2001, 2002, 2003, 2004 and 2005 Lexus IS300.
Does it fit the IS300 SportCross?
Yes. The K500066 and K500067 applications cover applicable 2002–2005 IS300 SportCross models.
Which side does K500066 fit?
K500066 installs in the front driver-side lower position.
Which side does K500067 fit?
K500067 installs in the front passenger-side lower position.
Does the kit include two ball joints?
Yes. It includes one left-side and one right-side front lower ball joint.
Are the joints pre-greased?
SCITOO states that its suspension components arrive pre-greased. Follow the supplied instructions and inspect each boot before installation.
Will the kit stop suspension clunking?
It can eliminate clunking caused by worn lower ball joints. It cannot repair loose sway-bar links, failed bushings, bad tie rods or worn shock mounts.
Will it fit a 2006 Lexus IS250?
No. It is designed for the first-generation 2001–2005 Lexus IS300.
Does it come with a warranty?
The listing advertises one-year replacement support. Confirm the current terms with the seller.
Is an alignment required?
An alignment check is recommended after replacing the ball joints or disturbing connected suspension hardware.
Final Verdict
The SCITOO K500066/K500067 kit is an affordable two-piece replacement option for the 2001–2005 Lexus IS300. It includes both side-specific front lower ball joints and arrives pre-greased for installation.
Confirm fitment, diagnose the suspension properly and inspect the control-arm bushings before ordering. Install the joints using the proper service procedure and finish with an alignment check.
There are no reviews yet.