Stiff king pin rotation
Posted: Wed Mar 27, 2019 3:00 pm
I am wondering if anyone else has had this problem with the lower suspension wishbone, and if so what the solution is…
Looking at the photo below you will see that once assembled, my off side top king pin trunnion doesn't line up with the chassis mount! I've slackened off all the nuts including the wishbone camber nut (they of course were not tight anyway), but there is still a 10 mm or so misalignment. If I first fit the 1/2" bolt through the top trunnion, then the 7/16" bolt will part fit through the lower chassis mount and the phosphor bronze bush but of course not through the other side of the chassis mount due to the misalignment.
[attachment=1]IMG_20190305_231619 (2).jpg[/attachment]
The near side king pin fitted ok although the lower 7/16" bolt did need winding though the mount. The king pin swivels with very little resistance so the near side is ok.
I tried swapping around the top wishbones but I had the same issues (and laying one over the other showed them to be identical). I did manage to eventually get all the bolts in, with the final bolt being that of the top wishbone front bolt (that also takes the anti-roll bar bracket) although it did need 'screwing' in and forceful alignment in order to align the chassis bracket with the mounting hole of the wishbone. This though results in very high resistance in rotating the king pin.
I noticed during my own little investigation that both suspension assembly sides went together very nicely if I swapped over the lower wishbones to their opposite sides and so mounted them upside down (i.e. damper bracket protruding from the top of the wishbone – a novel solution but quite incorrect! More interestingly I saw that the metallastic bush eyes were welded differently on each wishbone, one was axial to the tube and the other was clearly not!
[attachment=1]IMG_20190305_231619 (2).jpg[/attachment]
I returned the wishbones to the factory who said that although they fitted their jigs ok and to an XI chassis, they would send me replacements which they did. Upon receipt I did notice that what I returned and what I received back were not identical...
I’ve now fitted the replacement lower wishbones. The near side one went onto the chassis ok once I’d filed a small amount off the chassis pickup point a little, and the king pin rotates very easily.
The side I had the trouble with went together easier, although there is still significant rotational stiffness in the king pin (the top king pin nut is slackened off).
My question (bearing in mind that the car is going to be very low annual mileage) therefore is: how do I gauge the point at which the kingpin rotation is too stiff and will result in abnormal wear or even failure?
Many thanks for all comments.
Morris.
Looking at the photo below you will see that once assembled, my off side top king pin trunnion doesn't line up with the chassis mount! I've slackened off all the nuts including the wishbone camber nut (they of course were not tight anyway), but there is still a 10 mm or so misalignment. If I first fit the 1/2" bolt through the top trunnion, then the 7/16" bolt will part fit through the lower chassis mount and the phosphor bronze bush but of course not through the other side of the chassis mount due to the misalignment.
[attachment=1]IMG_20190305_231619 (2).jpg[/attachment]
The near side king pin fitted ok although the lower 7/16" bolt did need winding though the mount. The king pin swivels with very little resistance so the near side is ok.
I tried swapping around the top wishbones but I had the same issues (and laying one over the other showed them to be identical). I did manage to eventually get all the bolts in, with the final bolt being that of the top wishbone front bolt (that also takes the anti-roll bar bracket) although it did need 'screwing' in and forceful alignment in order to align the chassis bracket with the mounting hole of the wishbone. This though results in very high resistance in rotating the king pin.
I noticed during my own little investigation that both suspension assembly sides went together very nicely if I swapped over the lower wishbones to their opposite sides and so mounted them upside down (i.e. damper bracket protruding from the top of the wishbone – a novel solution but quite incorrect! More interestingly I saw that the metallastic bush eyes were welded differently on each wishbone, one was axial to the tube and the other was clearly not!
[attachment=1]IMG_20190305_231619 (2).jpg[/attachment]
I returned the wishbones to the factory who said that although they fitted their jigs ok and to an XI chassis, they would send me replacements which they did. Upon receipt I did notice that what I returned and what I received back were not identical...
I’ve now fitted the replacement lower wishbones. The near side one went onto the chassis ok once I’d filed a small amount off the chassis pickup point a little, and the king pin rotates very easily.
The side I had the trouble with went together easier, although there is still significant rotational stiffness in the king pin (the top king pin nut is slackened off).
My question (bearing in mind that the car is going to be very low annual mileage) therefore is: how do I gauge the point at which the kingpin rotation is too stiff and will result in abnormal wear or even failure?
Many thanks for all comments.
Morris.