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MG MGB Technical - brake disc removal?

now this may be the most basic of jobs and on a more modern car i wouldn't have a problem.

in short of do i get the discs off?
the 4 bolts that i think hold the hubs in place are lose but are now just turning?
i cant see how to get a spanner on the back of then or even if that's what your supposed to do?

my car has wires fitted, am i supposed to remove the large nut from inside the spline to?
if yes is it a normal thread and what size?

Haynes manual it not at all helpful in this mater.
cheers again
s truman

Truman,

My memory is a little hazy on this, I think because it is so simple that I didn't really pay any attention to how I was doing it. But, it sounds like you still have the hub attached to the car, and I think you have to take it off the car before you can replace the discs. So, if you are asking about the nut in the center that holds the hub and disc assembly onto the spindle, then yes, you have to remove it.

I guess maybe you are asking about the thread size because you are looking at the end of the grease cap. I don't know the size, but it is common like maybe 5/16 inch. Just take a look and pick a nut that fits.

Get two of those nuts and a long bolt. Screw one nut fully onto the bolt, follow it with the second nut, but just barely screw the second nut on. Then jam the second nut in place with the first one. Then screw the remaining threads of the second nut onto the threads you see in the hub. Then grab the head of the bolt with vice grips and smack the grease cap out with a hammer. That will expose the big nut that holds the hub to the spindle.

Charley
C R Huff

I thought Haynes was pretty good except for the fact you have to go between the chapters on 'brakes' and 'suspension'. First you must release the brake caliper and hold it back securely if you are leaving the brake hose attached. You then need to remove the hub which is only held in place by the central nut. This is 1 1/8" AF. The hubs usually come off very easily.
The four bolts you have tried to release actually hold the disc onto the back of the hub.
Follow Haynes re the outer bearing if it's not being replaced. Be careful not to lose/damage the shims.
Also have a look at Paul HUnt's website (www.mgb-stuff.org.uk) for some excellent tips on reassembling the bearings, particularly if you decide to replace them and need to re-shim.
Lastly, you'll need a torque wrench to ensure proper loadings on the bearings.
Richard

Richard Coombs

well ive sorted the caps in the hubs out one is missing and the other just pulls out.
is the centre nut normally easy to undue?
once the centre nut is off then the hub should just pull off with the disc still attached?
are the shims likely to fall out and leave me scratching my head....
s truman

The hub nut should be easy to remove, but it is castlated and should have a split pin through it. Hard to see if it's covered in grease!

Cheers,
Tim
T Jenner

I've taken my hubs off to replace the discs.

Grease cap can be removed just by putting an appropriate-sized pair of pliers in the hole, gripping the threaded stud and wiggling and pulling. Keep telling myself to make a puller, but haven't got a round tuit yet.

You have to poke and fish the split-pin out of the hole in the side of the wire-wheel hub, or you may be able to get a socket on the nub and simply shear the split-pin through. Nut is 40-70ftlb so not too bad, not like the rear hub nuts.

Take care removing the hubs as the outer bearing, shims and spacer tube will fall out as the hub is turned over. Remove these to a clean place while working on the disc.

The disc bolts are a real pain to remove. They are recessed into a channel and there is virtually no space to get a socket or anything else fully seated onto the head. I just managed to get mine undone by putting a tommy-bar in a socket on the head with its free end on the ground and a torque wrench in another socket on the bolt and pressing the two together to keep them in line as best I could whilst using the torque wrench to undo the nut. See http://www.mgb-stuff.org.uk/wn_brakesframe.htm and click on 'Calipers'. Really it needs some kind of jig to hold everything together and in line, or a wider channel for the bolt heads, or deeper heads.

I decided to repack my bearings before refitting. Only ever do it from one side and keep pressing it in until it bulges out the other side or you can get air spaces trapped inside. The shims *should* be correct if they were right before, but it's worth checking, see http://www.mgb-stuff.org.uk/wn_suspensionframe.htm and click on 'Front Bearing End-float'. Make sure you get the order of components correct - hub on first, then spacer, then shims, then outer bearing race, then sealing washer, then nut.
Paul Hunt

To get the 4 bolts out I used a special slim socket on and extension rod to a bar. I put the assy on the garage floor jammed one end of the socket bar on the ground and hit the end of the spanner on the outside with a mallet. Once started they spin off fine.
Stan Best

well thanks for all the imfo but i think after reading this i will be getting someone else to do it.
have bit of a phobia about bearing and drive shaft type of things! they normal go wrong in my hands leaving me peeded off.
s truman

This thread was discussed between 11/08/2009 and 12/08/2009

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