Rear wheel alignment

[blueabyss]

I recently replaced the three rear wheel bearings on my '97 XJ600 as part of a rear-end overhaul. I re-assembled everything as per the book and made sure that the spacer-tube was in place. When it was all back together, I noticed that the brake disc was not sitting in the centre of the slot in the brake caliper and was off to the left by about 3mm, as you look at it from the rear.

I have re-checked everything and not left any bits out. Any suggestions or advice would be very welcome, before I have to resort to using shims to move the caliper over.

[amorti]

I just cleaned up my rear caliper as it was starting to stick, and the outside piston does extend rather further than the inside piston when I put it all back together. Not sure if it's 3mm? but it's noticable. If you find it a problem, whack an M10 washer each on the caliper mount bolts, but I think it's normal? The whole assy is aligned against the wheel, so the only way it could be out is if the caliper bracket is actually bent.

edit: really? 3mm? I don't think the slot is big enough to allow the disc to be 3mm off of centre. On mine it's more like 1-2mm I think.

[blueabyss]

Thanks for your response.

To clarify; the issue is not with the position of the pistons, but with the position of the brake disc in relation to the caliper. It is not centred in the slot within the caliper and is almost touching it on one side.

I bought the bike a few months ago and it came with some serious rear brake issues. One of the caliper pistons had seized and been ignored by the previous owner until the disc had been trashed. He had attempted to change the disc but had sheered two of the mounting bolts, causing the disc to run out quite badly. I removed the disc and had the wheel heli-coiled before fitting a new disc and overhauling the caliper. I also changed the rear wheel bearings for good measure and, upon re-assembling everything, noticed that the disc was not centred within the caliper slot.

I have looked at it again tonight and estimate the gap on the left side to be less than 1mm and about 3mm on the right. The pistons should not have any bearing on this.

I am sure than I have replaced all the parts in the correct order and am wondering whether it could be due to the 3 bearings being off to one side within the wheel - I cannot remember any issues when I fitted them and they are snug up to the spacer tube.

[amorti]

Sorry, all I meant was that the off-centre causes the pistons to extend unevenly, that's how I noticed mine wasn't quite right. I will have a closer look at it this evening and post back.

If you have had work done, perhaps it's possible the disc isn't in standard alignment? Putting a washer on each caliper bolt isn't going to cause a problem, that's what I would do. Or ignore it, as long as there is no chance metal can touch metal, and not enough room for a piston to over extend and pop out.

If the bearings are snug to the tube, they have to be located correctly, all 3.

[CD]

Its possible you were sold a wider bearing, but if its not rubbing and the pads are wearing ok it should be fine.