SWIVEL BOLT DIFFERENCES - ONE OUT OF SEVEN IS DIFFERENT!!??

Tomorrow, hopefully, I will be attempting to get the swivel ball away from the axle on the D1, no doubt with quite a bit of swearing and cursing!

I am sure this is common to Discovery, Defender and probably Series but I didn’t know till today that one of the seven bolts, dowels as the Land Rover parts catalogue calls them, fixing the swivel ball to the axle is different to the others. There is one bolt with a shoulder diameter of 10.5 mm compared to the other six with a diameter of 9.8 mm. Part number for the 10.5 is you UYG500040 and the others are part number TYG100580. Apparently this is to do with setting the caster angle – how I don’t know.

I am fairly certain I have previously fitted swivel balls using one size throughout on previous vehicles so I wonder what happened to those!

Will be interested to hear if others knew this or ignored it and use the same bolts throughout??

Yes, but mine were all the same.
I would be interested to see how it affects the caster angle.

Does the 10.5 only go in 1 place so you can’t be an idiot and put it upside down

Who would do that.

J

marjon said:

Does the 10.5 only go in 1 place so you can’t be an idiot and put it upside down

Who would do that.

J

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Iv seen a calliper put on upside down on a LR.

Lots of truck brake calipers are like that, it just means the larger size is a much more accurate fit so the assembly is lined up as the engineer designed it to be.
I would say it is more to do with bearing/shaft alignment rather than any geometry angles.

Tbh I have never noticed when I have had my 90 apart, plus have read of a few people replacing said bolts with allen headed bolts, sure as eggs are eggs they were all the same diameter.

Cannot see any different dia bolt sizes listed in the s2 manual, but defender one does show them.

The bolt (with the shoulder) will fit accurately and align the swivel ball for correct castor. If all were set screws (full thread) the swivel ball could be rotated in either direction because of the clearance of the thread in the hole.

Brief update – with the aid of an induction heater, which I have written up in my other post on getting the swivel bolts out, all of them came out cleanly using a 9/16 ring spanner only.

Probably no surprise that all of the bolts are of the same diameter so whoever had the swivel off last didn’t use the larger bolt in the one location, though there is definitely one larger hole in the swivel to accommodate it. The large bolts are not much money so I have ordered one which I will use when rebuilding.

Thanks for the comments regarding why there is this one large bolt, alignment rather than anything to do with caster angle seems logical to me as to why it is there.

not sure these are for D1 but my defender has them now but not shown in the above manual but maybe worth installing to protect the swivel ball housing.