Hello, sorry if this sounds daft, but I have a question to ask reference the differences between 500SL (R129) power steering pumps. My car is registered as a 1993 model, but it appears to be the earlier pre-1993 model: - VIN - WDB1290662F061380 Engine - 11996022033843 Non-tandem pump model. Recently a minor leak on my power steering pump has become more serious (no it's not from the little rubber hose between the reservoir and the pump itself). I've been trying to source a replacement (used) pump for the car and am wondering what the model year differences are. It appears that the pump that I have fitted is a LUK with a part number of 129 460 0680. Unfortunately I have just accidentally ordered a used ZF with a similar part number of 129 460 2680 which I think is from a 1993+ model...... Do you know if these pumps are interchangeable? I was hoping to get someone to help me swap the pumps out whilst I re-build the current one (once I source a new gasket kit). Any advice would be greatly appreciated. Kind Regards Andy.