Rear brake caliper carrier slide/guide pin question

Just getting some Audi TT carriers ready for upgrading my rear brakes to 256 vented.

The carriers are s/h bought as a pair from ebay.

The guide pins that came with them installed are the same length, diameter and design  (3 flats machined on the pin)

On each carrier one of the pins has more side to side movement (when inserted in the carrier) than the other as if the carrier has one slightly larger diameter hole. I have seen that other designs of guide pins have a stepped down diameter that gives this same feeling and as it is designed in then has some purpose. It seems to me sensible to think that the pin with more movement should be either top or bottom when installed on both sides. however on the s/h set I have on one side it is top and the other bottom. Also on the TRW new or recon BDA526 and BDA 525 carriers (bought for another purpose) which does have the stepped down design pin  these also do not mirror each other ie slider rattles in the top of one and bottom of another. Maybe they were wrongly assembled at the factory.

Can someone shed any light?

Mark

Edited 2 October, 201411 yr by MarkyD