SI Caliper/disk positioning

Thistle Grey · Nov 16, 2014

I am having trouble centering the S1 calipers on the rotors. I am using the original SI axles, with the original distance pieces still in place. I have a set of rebuilt calipers and freshly turned rotors, both from either the SI or SII and have assembled them with the wire wheel hubs from the SII. When I mount the hub and disk assembly, then the calipers, the disk isnâ€™t centered in the caliper, it needs to move inward almost 1/16â€. I used some clay to confirm that the rear bearing is flush to the distance piece, so it canâ€™t move any more inboard, , and the caliper obviously is fixed in position as well. The WSM suggests spacers between the caliper and axle, but that would move the caliper further in the wrong direction. It looks like I need a narrower distance piece to move the hub assembly further inboard, but those arenâ€™t available. Any suggestions? It seems like Iâ€™m missing something obvious.

Thistle Grey · Nov 17, 2014

How about a simpler question. It looks to me like I either have to replace the distance piece on the axle, or put a spacer between the disk and hub. (really don't like the sound of that). Has anyone ever done either of those?

junkman · Nov 17, 2014

caliper

If the rotor doesn't rub the caliper, a 1/16th difference shouldn't be a problem as both pistons will equal out and exert the same force on your rotor. But if you cannot get the caliper on because of this pull the shim and grind it to the right size. (nobody will ever know).
Jeff

Thistle Grey · Nov 17, 2014

Ok, as it is now I can't get the outside brake pad in because the rotor is too far out of center. When you say "grind it" are you referring to the back of the brake pad or the caliper mount?

bernd_st · Nov 18, 2014

Pictures would help. Very obvious, but did you mount the rotors to the hub in the correct orientation, i.e. going inwards ?

Thistle Grey · Nov 18, 2014

Three photos attached to show the issue. The â€œdistance spacerâ€ on the axle is in place and fully seated. The hub and disk assembly is correctly assembled and tightened on the axle as per the WSM and there is no gap between the back bearing and the distance spacer. With the caliper mounted, I canâ€™t get the outside pad in even with piston all the way in. Seems like I must be missing something. ??

junkman · Nov 20, 2014

distance spacer

the distance spacer could be ground 1/32 off each side then she'll go

Thistle Grey · Nov 20, 2014

Any suggestions on how to pull the distance spacer? WSM says to split it and replace it. I can't fine any replacements so I am concerned about damaging it or the axle trying to get it off.

junkman · Nov 22, 2014

heat it with a torch it will come right off

Toyanvil · Nov 23, 2014

Where is the backing plate?

Gary T · Nov 25, 2014

SI Disc Positioning

I am assuming that you replaced the bearings in the front hub. If so, is it possible that the inner race is not seated to the bottom of the hub? This is worth looking at since if it is not properly seated it would offset the rotor even though the bearing is touching the distance spacer.

Since I have not seen any source for a replacement distance piece I would not remove the existing one which would be damaged if following WSM.

While heat may remove the distance piece depending on the amount of heat could also damage the distance piece as well as the spindle. they are both heat treated for hardness.

Thistle Grey · Nov 26, 2014

Good thought Gary, I pulled the hub and rotor off the left side last night and test fit it onto the right side and there was no problem with the fit. That would match with your idea that the bearing may not be properly seated. I'll pull the right hub apart and see what is going on in there.