Wheel bearings are one of those critical parts that often ignored these days. Normally they die a slow and noisy death, but because of this the howling sound of a dying bearing is can be subtle and masked by ordinary road noise or simply turning the radio up a little higher. Then one day , you’ll really hear it or you’ll be taking a wheel off and notice some up/down slop in the wheel. So then what? Is it something you can DIY?
Yes, absolutely. There are two distinct types of wheel bearings. The first has not changed much in 100 years and is used on pick-up trucks, landscape trailers and lots of Mercedes-Benz and Volkswagen vehicles. These are simple tapered roller bearings that need to have the proper pre-load set on them by tightening the axle nut. Very serviceable , but need to be serviced (greased, checked) more often.
The second type I’ll cover in this article is the sealed cartridge bearing. This bearing is press fit into the wheel hub and is not serviceable for its lifetime. From my experience, that is between 100,000 and 150,000 miles on average. Most manufacturers have moved towards this type of bearing and although slightly more expensive, should provide maintenance-free operation. Installation procedures are critical as improperly installed bearings can wear out prematurely and cause you to repeat the process. The cost savings by doing this job yourself can be drastic. Even if you have to pay to have a mechanic or machinist press in the bearing.
In this instance I’ll be installing a front wheel bearing on a 1986 SAAB 900, but the processes is almost identical across many makes and models using this style bearing. The bearings are installed by having an interference fit that is pressed into both the wheel hub and the steering knuckle.
– Impact or Hand tools to remove knuckle assembly from the vehicle
– ball joint or tie rod end popper may be required.
– Internal Snap Ring Pliers
– Large hammer/sockets
– Hydraulic Press (or take to your local mechanic/machinist)
First step is to remove the whole assembly from the vehicle. On some vehicles it is possible to do the replacement with special tools, but in this case I find it much easier to have everything off the car and to use a hydraulic press.
These hubs were taken off of a parts car so the rotors and calipers were still attached in a greasy lump of rusty metal. Taking off the rotor and caliper made the assembly much easier to work with.
Next , use a punch to loosen up the snap first snap ring. Just by hitting the ends and rotating the snap ring around will significantly make removing it easier.
After the snap ring is removed I removed the ball joints as I was completely rebuilding this assembly and these ball joints had had enough. A pickle fork (link) and hammer popped them right out. If they were in good shape I would have plenty of room to work around them and leave them be.
The splined part of the hub that is pressed into the inner race of the bearing need to be removed. This can be don on a press with special fixtures OR with using a properly sized socked and a large hammer, with the steering knuckle held securely in the in a vice.
Here the hub knocked out with the socked I used. It is fairly common for one of the inner races to stay on the hub. This needs to come off as well. You can use a split bearing puller or a simply slice the race (being careful not to cut the hub) and knock it off.
With the hub removed you can now gain access to the brake dust shield bolts to remove and replace later on.
Next we load the hub and remains of the old bearing into the hydraulic press to do the final removal. I used another sealed bearing that is slightly smaller to press through the steering knuckle. Finding a combination of old parts you can cobble together to use for holding and pressing is generally the most time consuming part, but once you’ve found a good setup, it is quick work.
Now that everything is apart it is a good time to clean , paint and inspect.