Friction pads

Hi all,

I have recently purchased replacement friction pads for my AKS 2004 hitch on my caravan. Unfortunately the replacement items do not fit. The shaft is physically different between the removed part and the replacement (see picture attached - note the friction pad has sheared). When i enquired at my local dealership they were only able to offer the same pads as i had bought. Does anybody have a similar experience of this or know of any differences within the AKS2004 series that would explain which pads i need. The finishing caps were the small red type and not larger black ones if that helps.

Thanks in advance.

Andy