09 February 2019

CV Axle Replacement - Audi A3 (8PA)

Today we are going to replace the front right CV axle on the Audi A3.

The outer boot was damaged probably some time ago and there is no grease left in it, also there is quite a bit of play in the cv joint so I figured it's probably best to replace the whole axle before it fails completely.

To replace the axle you will need the following tools:

- a 27mm socket with a long breaker bar; you'll need this to remove the hub bolt that's keeping the outer CV joint in place

- a long 19mm socket to remove the 3 nuts that hold the lower ball joint in place.

- an 8mm spline bit, also know as a triple square bit, to remove the 6 bolts that hold the inner CV joint bolted to the gearbox.

Before you jack up the car, remove the center cap with a screwdriver and using the 27mm socket break loose the hub bolt. Do not loosen more than 90* at this point or you'll risk damaging the wheel bearings.

Jack the car up, secure it on jack stands and proceed to remove the wheel normally. Now you can completely loosen and remove the hub bolt. To prevent the axle from turning have a second person to apply the brakes or stick a screwdriver into the ventilation slots of the brake disk.

Next, using your 8mm spline bit remove the 6 bolts holding the inner CV joint. This will be fiddly and messy.

As a final step, using your 19mm long socket or spanner, remove the 3 nuts that keep the lower ball joint bolted to the suspension arm. Once removed gently pull the whole hub assembly towards you until there is enough space for the axle to slide out. If the axle is stuck in the hub, thread the bolt halfway in and give it some gentle taps with a hammer.

For installing the new axle, follow the same steps in reverse. Do not forget to grease the inner joint and carefully align the rubber seal, that goes between the joint and the gearbox flange, with the bolt holes.

The final step is to tighten the hub bolt. You have to do this while the car is still jacked up or you'll damage the wheel bearings. Block the brake disc or have a second person applying the brakes. Using your 27mm socket and the breaker bar tighten the bolt as hard as you possibly can (200nm if you have a torque wrench). Put the wheel back on and lower the car to the ground. Now you can further tighten the hub bolt another 90*, if necessary.

Take the car for a spin, it's entirely possible that the new axle will be noisy in the first couple of corners, until the grease reaches every nook and cranny of the joints. If the noise persists you did something wrong or the new axle is defective. Good luck.