How to Replace Yamaha YFZ450R Ball Joints
Ball joints on ATVs go bad, which is natural given the abuse they take out on the trails. Changing the ball joints on a Yamaha YFZ450R takes only a handful of tools and a bit of spare time.
Watch the video above and follow the steps below to replace the ball joints on a Yamaha YFZ-450R. Use our YFZ450R front suspension parts diagram for additional reference.
Tools and Parts – Yamaha YFZ-450R Ball Joint Replacement
- Ratchet and extensions
- 12mm, 14mm, 17mm sockets
- 14mm, 17mm wrenches
- Punch tool
Yamaha YFZ450R Lower Ball Joint Replacement
Step 1. Remove the lug nuts and front wheel.
Step 2. Remove the cotter pin and castle nut that secure the lower ball joint to the steering knuckle assembly.
Step 3. Remove the shock absorber bolt that attaches the shock to the lower A-arm.
Step 4. Remove the two lower A-arm bolts that attach the lower A-arm to the YFZ450’s frame.
Step 5. Drop the lower ball joint down and out of the steering knuckle assembly.
NOTE: You may have to use a punch tool and a hammer to break the ball joint free from the knuckle.
Step 6. Remove the lower ball joint circlip from the lower A-arm.
Step 7. Place the lower A-arm and ball joint over a piece of 1 ½-inch metal pipe so that the pipe is supporting the A-arm, and the ball joint is over the void in the pipe.
Step 8. Press the lower ball joint down out of the lower A-arm and into the pipe.
Step 9. Turn the lower A-arm over, then place it over the 1 ½-inch metal pipe again and press a new ball joint into the A-arm.
Step 10. Install a new ball joint circlip into the lower A-arm to secure the ball joint in place.
NOTE: If you’re replacing both the upper and lower ball joints, don’t reinstall the lower A-arm back onto your YFZ450R yet. First read Option A and Option B in the Upper Ball Joint Replacement section below before reinstalling a lower A-arm.
To reinstall the lower A-arm, simply work backward from Step 5 to Step 2. Torque the ball joint castle nut to 18 foot-pounds; the shock absorber bolt to 40 foot-pounds; the lower A-arm bolts to 32 foot-pounds; and the wheel’s lug nuts to 32 foot-pounds.
Repeat Step 2 through Step 10 for the lower A-arm and ball joint on the other side of your YFZ450R.
NOTE: Always replace the ball joints on both sides of an ATV at the same time, because when one ball joint fails, the other soon follows.
Yamaha YFZ450R Upper Ball Joint Replacement
The Yamaha YFZ450R is designed so that the shock absorbers run through the upper A-arms, which prevents them from being removed as easily as the lower A-arms. To remove the upper A-arms, you have two options:
Option A. Remove the upper A-arms when the lower A-arms are already removed. This only requires disconnecting the upper A-arms and dropping them down over the lower (disconnected) ends of the shocks.
Option B. Remove the upper A-arms with the lower A-arms still in place. This requires you to remove the shock absorbers first.
PRO TIP: Any time you remove the lower A-arms to replace the lower ball joints, use the opportunity to also remove the upper A-arms and replace the upper ball joints.
After choosing Option A or Option B, replacing the YFZ450R upper ball joints is essentially the same as replacing the lower ball joints. The only differences are that the shock absorber doesn’t attach to the upper A-arm, and there’s a brake hose housing attached to the upper A-arm just inboard of the upper ball joint that must be removed. Other than that, the procedure to unbolt the upper A-arms from the frame and steering knuckle assembly is the same, as is the method for pressing out the old upper ball joints and pressing new ones in.