I am just putting the wheel bearing back together on my MG B GT. How
tight do I do up the castellated nut?
The haynes manual says to the specified torque, but I do not have a
This site  says do it up tight, then lossen it, and do it up again
until it makes contact, then do it a bit tighter if there is any play.
I am finding it hard to determine the difference between play in the
suspension and the bearing, and I cannot feel a definate point that
play stops between completely loose and done up as tight as I can.
Any pointers, please? Thanks.
I take it this is a front bearing?
If so, I always used to tighten these up very slightly with a bar (and I
mean very slightly), back them off and then tighten by hand. It can help
to do this with the wheel on and give it a wiggle as you tighten the
nut, keep tightening until you can't feel any play on the wheel - this
is literally to the point that the play stops, if anything leave some
play rather than overtighten.
Andy Hewitt ** FAF#1, (Ex-OSOS#5) - FJ1200 ABS
Honda Civic: Windows free zone (Mac G5 Dual Processor)
from firstname.lastname@example.org contains these words:
My Haynes says 40-70 ftlb - which is a huge range. Between "Not terribly
firm at all" and "Mdium tight". It also gives a long and complicated
procedure for getting the right shims in the front bearings.
You could go buy a torque wrench - Argos do 'em for a tenner or so.
Thanks for the pointers. I have found out why I could not tighten in
up enough to stop the play, it is because the play is in the ball
joints. Oh bother. I guess I shall have to take them apart tommorrow.
Probably I will just have to change the shills?
There shouldn't be any play in the suspension. A small amount of play in a
taper wheel bearing is OK, though. But has an MGB taper bearings? Things
like the earlier Austins that used the same type of suspension weren't.
However, if it is an adjustable type, tighten it moderately with a spanner
to seat the bearings. Then slacken. Then tighten with your fingers as
tight as you can and back off to the first hole. You won't be far out.
Something like 5mm movement at the top of the tyre is OK.
*Why isn't there mouse-flavoured cat food?
Dave Plowman email@example.com London SW
I replyed before I saw all these messages. Bloody google.
So, there is play at the top and bottom of the bit of metal marked 21
in the diagram at . This is wrong I belive? This piece is known as
the swivel axle?
I guess I need to carry out the procedure as described in the haynes
manual as "Swivel axle and swivel pin (kingpin) assembly - removal,
dismantling, reassembling and refitting". Bother again. That involves
removing the coil spring, could be a bit of a job. What do you reakon
about the chance of 2 relatively inxperienced but vaguely practical
blokes doing it this weekend?
My mate reakons I will only need change the shims. What do you lot
You should buy a set of axels and pins and replace the units - the
bushes which are pressed into the swivel are reamed to suit the pin.
Both the pin and the bushes will be worn as well as the lower horizontal
Assembly will have to be setup and shimmed then put into place.
Buy all the parts in the front suspension you should replace them all.
Thanks for all the pointers. I decided I was not quite up for a
complete suspension rebuild today, and I gave it a good greaseing and
that stopped the movement. I guess that will do for the minute. I
shall have to fix it properly when I have a bit more time.
Anyone any idea how long I could expect to drive it in this condition?
have a look at www.mgcars.org.uk.
Categories there for most groups of MG's. (General and Technical groups for
Membership (free) is not needed, however you cannot search the archives
unless you join.
Assuming they are Timken taper bearings, the nuts should not be tight at
In effect the nut is only used to adjust, and set the play in the bearings.
The aim is to have as little play as possible, so even after they're set,
the nut is not actually loading the bearing at all. Up to 0.75mm play at the
wheel rim is permissable.
Which might be the difference between a setting that's too tight and a
looser setting where the split pin can still be fitted.
Initially they are lightly tightened to ensure everything is seating
properly. Then backed off and adjusted as above.
Some of the advice that has been given is misleading.
The factory setup on a MGB has a spacer between the bearings, and end float
is adjusted by adding or removing shims. NOT by tightening and slacking the
The correct end float is 0.002" to 0.004" This is obtained by adding a
surplus of shims, tightening up to 40 lb.ft, measuring end float with a
dial guage, and then reducing the shim thickness by removing shims to give
the correct end float. You must ensure that there is sufficient shimming in
place for the initial tightening and end float measurement. Having less that
required may damage the surfaces of the bearings.
The correct torque is 40 to 70 lb.ft. This is obtained by tightening to
40lb.ft and then going to the next spit pin hole.
The whole process is best carried out with all components dry and clean, and
the oil seal removed.
Once the correct end float is obtained, dismantle again, grease the
bearings, replace the seal and reasemble.
They are taper roller bearings, but they do have spacers and shims. I assume
that whoever designed the setup had reasons.
While the system on a MGB would appear to be different from a 'normal' setup
for taper rollers on other breeds, the use of a spacer was consistent with
MG practice on the MG Y type, followed by the TD, TF, MGA, and also used on
the AH Sprite/MG Midget, although all these cars used ball bearings.
It may have also been consistent with Morris and Austin practice on other
cars as well.
It may well be that the use of a spacer on the MGB was a carry-over from
earlier practice, but the use of a spacer in compression adds greatly to the
stiffness of the stub axle, ensures location and alignment of bearing inner
races, and prevents rotation of the inner races.
I agree that it is easier to setup a MGB bearing without shims and spacers,
but from a design point of view it should be kept in mind that this may not
meet the requirements that the designer intended.
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