Yesterday I replaced the drums and shoes on my car with stepped Cooper S items all round, and now I have a shudder that seems to be coming from the front right wheel when braking.

Obviously I had to remove the drive flange to replace the studs, but as the grease inside still had its original yellow colour I elected not to replace the wheel bearings yet. The brake cylinders also looked as though they had recently been serviced (was told they were when I bought the car earlier this year) so I left them alone for now.

It feels like the drum is not perfectly round, if that is possible. I did note when adjusting the shoes that it would catch at certain points when rotated.

This morning I will put one of the old drums back on and readjust to see if the 'catching' is still there.

Is it possible that the new drum is not perfectly round? What else should I be looking at?

Cheers
Terry

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My '78 Leyland Mini on flickr

I had a poke around in the seach bar ant the two most common problems are oval or "crowned" drums and the studs not pulling through the hub squarely. Hook up a piece of wire and set it close to the outer drum surface, spin the drum and watch, if the gap closes between the wire and the drum then it's not cocentric anymore.

Edit* if you can feel it through the steering wheel it's the front drums.

When you installed the new studs, did you tighten them home by bolting a wheel on?

Or did you hammer them home?

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You're so square
Baby I don't care

all of the above are possibilities...and I would suspect the new shoes....

they often have high spots on them and need bedding in...when you remove the drum you may see a furry part (the low or high spot) and elsewhere, mostly shiney friction material

also may be too fat??

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"Show me the Mini!"

I put the flange in a vise, used an old socket as a spacer and pulled them in with the old wheel nuts. The only hammering I did was to tap out the old studs after they had a good soaking of inox.

When I undid the castellated nuts they were both very tight, however I only did them up to 60ft/lbs. Should I have done them up as tight as the previous gorilla did?

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My '78 Leyland Mini on flickr

I'm thinking YES!

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"Show me the Mini!"

There have been cases recently of some new drums being oval inside.
This happens when the castings are not aged enough to reduce stresses, before machining.
In the old days they left them to weather for weeks or months, these days they `age' them via heat treatment instead. Sometimes the Chinese/Indians get this step wrong...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

60ft/lbs is correct I believe.

It's the cooper S drive line that is 150 or so. People tend to thing "If the race version is 150, I'll do mine to 150 too!"

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You're so square
Baby I don't care

After putting the old drums back on and adjusting them, I found they still caught the shoes in one place. So I would assume the issue is the drive flange and new studs not being quite right.

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My '78 Leyland Mini on flickr

Are you using the 2 locating screws in the drum? If you are, try without them.

How did you fit the new studs, if you bashed em in they may be bent or crooked....
Or maybe the new aftermarket studs are not of Original Mini Quality (ie, straight).

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I did this doc:



I just pulled the flanges off again and repeated the above process to ensure they were all seated properly. On close inspection it appears one stud may not be seated square to the flange, or the head may just be slightly fatter on one side, its hard to tell. However after a short test drive, it is significantly better but still not perfect.

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My '78 Leyland Mini on flickr

So..... I ended up replacing the drive flange with the 'crooked' stud with a second hand flange, and had some improvement. Most notably the drum now rotates without catching the shoes.
As the issue was still there I decided to investigate a little further and have found one of the balls in the inner CV (or is it a slip joint?) was floating around loosely. So before I do anything else I will be checking and re-assembling the joint.

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My '78 Leyland Mini on flickr

Hmmm, one of your balls fell out

Seriously but, the ball falling out cv shouldn't affect brakes. Usually, if that happens you get shudder under accelleration. Try swapping 'suspect' drum to another wheel, say back, see if problem follows.

I've also been supplied a number of new ones that had the register machined over-size and so don't locate positively, ie they flop around a bit on the hub

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