I recently change the front and rear discs/pads for the MOT. (Volcane TD.) They performed well but the inspector said there was some run out on one of the rears. This was indicated by a fluctuating reading during the test.
I know what run out is but didn't have the tools to check for it at fit! I made sure the hub face was cleaned, I used a wire brush, and a small quantity of antisieze was applied. Was this the error??
My real question is, how can I rectify the fault before it's too late? Can I simply rotate the disc on the hub to find a better surface? Will it just be trial and error.
Brake Run Out!!
Moderator: RichardW
I think it will just be trial and error; in cases like this just taking the disc off and putting it back on again should fix it-have a look and make sure no bits of grit or anything got stuck behind it when you put it back on.
If the runout is still there its probably a faulty disc.If you haven't got a dial gauge you can still do a reasonably accurate check by tying a screwdriver or pencil to an axle stand, putting the point next to the disc, and then spinning the hub; if any distortions are present they will show as a fluctuating gap between the disc and pointer which you can measure with a feeler gauge to see how much it is; comparing both rear discs will help.
If the runout is still there its probably a faulty disc.If you haven't got a dial gauge you can still do a reasonably accurate check by tying a screwdriver or pencil to an axle stand, putting the point next to the disc, and then spinning the hub; if any distortions are present they will show as a fluctuating gap between the disc and pointer which you can measure with a feeler gauge to see how much it is; comparing both rear discs will help.