Replacing A Front Wheel Bearing
by: Fastmike
Instructions
Unfortunately no photos for this guide, I went in blind doing it for the first time, so you will too sadly.
Hub assembly.
When wheel bearings fail, you can hear them with a quiet grinding noise.
Firstly, a new wheel bearing from a parts shop will be between £30 and £40, mine came with new driveshaft nut, circlip
(which was the wrong size), bearing, bearing grease and grease seal.
The bearing is a whole unit pregreased already, there are a few main parts to it. First is the main shell, this
combines two races on the front and back, and grease seals on either side of the balls. Second is two roller bearing
sets running in the outer races front/back. Third is a set of TWO inner races, which run on the bearings front/back.
Now pay attention, these two inner races can easily seperate when you put them on the hub. You have to check they
haven't seperated otherwise this bearing is as much use as the old one!
You have to remove the steering knuckle from the car, this involves removing the strut bolts, balljoint bolts (it's
easier than splitting the balljoint), the ABS sensor if it has one, the CV joint shaft, brake disc/caliper and the
track rod ends.
The CV joint will be the most difficult, if the joint wasn't replaced recently then you'll need to bash the joint out
which is very time consuming, even removing the nut is a problem. Luckily I did mine recently so they slide out easily.
You can only remove the CV joint/driveshaft from the hub when it is seperate from the suspension arm or suspension strut.
I had problems with the strut bolts, they were seized in the knuckle, one had to be hacksawed off and the remaining
bolt was taken out at the machine shop I used.
When you get the steering knuckle off, there is three parts that will need removing to replace the bearing. The bearing
itself, the wheel hub (pressed into the bearing), and the knuckle. The bearing is pressed into the knuckle and secured
with a circlip. You might be able to remove the bearing with a hammer and bit of tube but it's easier to take it to a
professional machine shop.
You can easily remove the wheel hub yourself, however the inner race on the bearing will come away, and might need
grinding off.
I recommend taking the whole knuckle/bearing/hub to a machine shop who should have the tools to press the hub out,
then the bearing - make sure they are aware there is a circlip holding it in place. Once they have them out they
can put the new bearing in and circlip within a couple of minutes.
My machine shop - who are a specialist engine rebuilder - did it there and then, and only asked for a fiver!
Take the knuckle home and fit the oil seal. Remove the old one with a flat blade screwdriver, it has a metal lip so
get under it and lift it out. Clean the inside area with a cloth and check the inner race on the back hasn't moved
out when it was pressed onto the hub. You can use a large (35mm) socket to tap the inner race back into the centre,
or use an inner race off the old bearing. You can tell the race is back to centre as it won't move any further and
the hub will turn very freely. Put the oil seal (metal first) over the hole it fits into, tap it in using the main
shell of the old bearing. Take the bearing grease and slob it into the gap and over the rubber. Check the hub rotates
very freely.
Refit the knuckle to the balljoint/suspension arm. Slide in the CV joint shaft, put the nut on by hand. Refit the
strut and strut bolts, then put the track rod end in the knuckle and refit the nut. Tighten up all the nuts and bolts,
refit the ABS sensor and brake disc/caliper. Tighten the CV joint shaft nut up until you can't tighten any further
with it in first gear and the other wheel on the ground. Check the CV joint is at the oil seal. Put the wheel on and
finally tighten the shaft nut up as tight as it was. Lift the wheel up with the jack and check once again it freely
rotates.
It cost me £40 for the bearing, £5 for the machine shop work and £1 for new bolts. Took about 5 hours.
Here's a diagram I did in Paint
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