@OEM+ DUB on here uses Golf ball joints on Passat alloy wishbones without an issue As he told me, you just need to make sure you use the Passat/S3 shouldered nuts.
The difference between S3/Passat and the Golf BJ looks to be roll centre correction? The tapered pin is longer on the S3 ball joint, because I assume it's ride height is lower than the GTI's? This will correct bump steer.
You could, and probably should, use the S3 ball joints on a lowered Golf?
I've got the Passat wishbones and bearing housings also, and brand new Golf ball joints from VW ready to go. But I'm thinking the same as you now, should I switch to S3 BJs?
Apologies for the thread resurrection but its relevant ...
I fitted S3 alloy knuckles/hubs and wishbones to a 2010 Tiguan and used genuine VW TIGUAN ball joints ... properly aligned and 18 months and under 10,000 miles later they are both 'split' and leaking grease!
I have an alternate theory about the benefits (necessity?) of keeping to an S3 balljoint on the alloy hubs - using the shorter golf/tiguan item lets the knuckle/hub push down on the rubber boot too much and squashes it?
I don't have bare hubs available to measure but I would imagine that the alloy units may well be thicker than the steel units at this point. In other areas they are thicker than the steel ones to get the strength. I'll be stripping the joints off the old steel knuckle at some point so will be able to do some vernier caliper measurements of the parts then.
Just to throw a spanner in to this all, the alloy wishbone / balljoint combo I received was marked up as for a Q3/Tiguan but had the S3 balljoints on so I took these off and saved them. Does the Q3 (R/SQ3?) have alloy wishbones and knuckles as stock?
Any thought on this?
I think I will be pulling the driveshafts out next spring and, unless an assessment shows anything else to consider, will be putting S3 balljoints on my stock height Tiguan next spring and get it re-tracked to suit ...
I'm at a loss as to why this has happened besides its not actually a compatible part - any thoughts / suggestions welcome ;-)