In <01BB1664.07A1B740@mmann.ccmail.COM>, Melissa Mann wrote:
>I have a 1980 MGB, and I need to replace my right rear wheel bearing, so I
>have a couple
> of questions:
>>1. Is this really difficult to do? My brother has offered to help, and
>while I
> trust his mechanical abilities, he has never replaced a wheel
> bearing.
>>2. Are any special tools needed for this job?
>>3. Should I also replace the left rear wheel bearing?
1. Not terribly difficult if you have the right tools and use common
sense.
2. You will need two special tools to do this job. You will need
something like a slide hammer and some means of attaching it to the
axle to extract the axle/bearing assembly (see below). You will need
a pipe of the appropriate diameter to press the new bearing on (hardly
a special tool, but you will probably have to go looking for one...)
3. You haven't said why the right wheel bearing needs replacing. If
the right bearing is noisy (and it isn't dragging brakes) then it
probably needs replacing. These thing generally don't wear out, so I
wouldn't worry about the left one unless there is a reason (noise).
The usual reason they go is that some crud gets into the bearing and
abrades it, but excessive miles is not generally the problem.
On the other hand, the bearings are fairly cheap, you might want to do
it on principle if you have all of the special tools assembled....
How to do it: There are two tricky parts, getting the gonzo axle nut
off and getting the axle shaft out of the housing. (1) Jack up the
rear end, chock the front wheels. Use a jackstand to stabilize the
car, don't trust the tire jack supplied. To have the car fall off the
jack can ruin your day. Remove the right rear tire. (2) Remove the
cotter pin holding the axle nut. This can be awful to do if you have
wire wheels since it has to be fished through a little hole in the
hub. If you have disk wheels it is pretty straightforward. (3) Put
the car in first gear and set the emergency brake _hard_. You will
need the appropriate socket (I forget the size, sorry) and a _long_
breaker bar or piece of pipe. (These might also come under the
classification of special tools, but if you have a British car, they
are not considered special....) This nut is on the axle with about
200 ft-lbs of torque, so it requires lots of jumping up and down to
get it loose. Both axle nuts loosen counter-clockwise. (4) Remove
the nut, release the emergency brake and remove the brake drum, which
is bolted to the hub with standard SAE hardware. (5) Use a large
three-legged wheel (gear) puller to pop the hub loose from the axle.
The puller might also seem to be a special tool, but see the note
about British cars above. (6) Remove the four screws that anchor the
brake backing plate to the axle housing. Remove the connection from
the brake line to the brake cylinder on the backing plate. Remove the
brake backing plate. (7) This step depends on how you attach your slide
hammer to the axle. I attached the wheel puller to the end of the
slide hammer with a nut (substituting the shaft of the slide hammer for
the drive pin of the puller). I then loosely put the hub back on the
axle and loosely spun the large hub attachment nut back on. The puller
legs then fit onto the hub. A couple dozen slams on the slide hammer
then is sufficient to pull the bearing out of the axle housing. (8)
You can knock the outer housing shell off of the old bearing easily.
Removing the old bearing from the axle is a different story. Since
it will be discarded, I gently "drifted" it off the axle with a brass
hammer. You may be better off taking the whole thing to an auto machine
shop to have the old bearing pressed off and the new one pressed on.
(9) If you press the new one on yourself, make sure not to put any lateral
pressure on the outer race. Bearings are not made to do that. Use a
piece of pipe that snugly fits the _inner race_ to drift the new
bearing onto the axle.
Reassembly is the reverse of the above. I usually put a very thin
layer of sealer (Permatex, Hylomar) on the outer bearing housing face
(that mates with the axle housing) just in case, since this joint can
leak oil. Remember that the axle nut should be torqued to at least
200 ft-lbs, which is a big guy leaning substantially on a 4 ft pipe.
Also, don't forget to bleed the brakes (at least the right rear
cylinder)!
This may sound daunting. It isn't, if your ducks are in a row before
you start. I estimate it as about a 3 hour job, with
>
>Thanks for any help you can offer!
>
You're welcome.
Good luck! A. B. Bonds
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