Brake disc wobble compensation?

[Ducman]

Pelican lists two different rear M caliper rebuild kits. One for brakes with disc wobble compensation and one for brakes without. I've rebuilt rear brakes in past but don't remember having to id this feature....so now not sure what I did.

How do I tell if caliper has this feature?

[clarkd]

If your pistons are cup shaped, they are not anti wobble. Anti wobble calipers have a shaft that a "widget" rides on. The seals are different between the two types.

[Ducman]

Thanks, but can you provide any additional details...my caliper piston cavities do have a shaft that the piston rides on...is this anti-wobble?

[clarkd]

This is an anti wobble piston. The inside opening for the seal used for this type of piston is smaller than the cup shaped piston.

[clarkd]

If you have the shaft and the style piston above, you need the kit for the disc wobble compensation.

[Ducman]

Thanks - was pulling them apart as your post came through. Yes I have the anti-wobble / wobble compensation style. Here are some additional pictures for reference should anyone search this in the future. Crazy thing is - I went back to my records and saw that I last rebuilt rear calipers in 2005. Pelican had a different part number convention back then but it looks like I purchased a seal kit for non-wobble compensated caliper. Seems to have worked for 10 years!