kingpin shims

Hi all,

The kingpin is supported top & bottom in a pair of taper rollers which can be shimmed to achieve the correct bearing pre-load. Now, do you have to shim top & bottom bearings separately, or are things arranged so that a shim top or bottom will tighten both top & bottom races?


cheers,

Martin.

Take a look at this.
www.lines-associates.com/store/index.php...product&product_id=8

dirtydogz wrote: Take a look at this.
www.lines-associates.com/store/index.php...product&product_id=8

I thought the preload was correct without shims.

thanks guys,

But...surely the preload isnt always spot on or there would be no need for shims. These kinds of bearing always bed in & wear & so on ...so some form of adjustment has to be a good thing on a taper roller.

I havent had one apart (yet) & am simply trying to understand how it works. I imagine it is very like the steering head on a motorcycle which often use a pair of these bearings. They need regular preload adjustment & if you dont bother the bearings loosen & begin to get pitted. Once this happens they are scrap & the steering will go to hell.
Maybe this is why the Jimny kingpins don't last too well as there is no regular adjustment of them??

Anyway the question is still there. Does shimming one bearing tighten both top & bottom & if not why not?

thanks Martin,

Before I bought my car the Suzuki dealer carried out the service bulletin to rectify some steering wobble. I noted on the report that only 1 shim was added each side. From the disturbance it looks like these went on the bottom. Anyway, the wobble is sorted but I am a bit concerned that by adding only 1 shim it might displace the hub (up in this case) and load the drive shaft bearings as the shaft alignment has been moved by the thickness of the shim. Is this likely to be significant, or am I worrying over nothing...?
When the weather improve I plan to shim the kingpins properly myself top & bottom as you have recommended. Just dont want anything to be damaged in the meantime.

Sorry to go on about this but that's how you learn..


cheers,

Martin.

Greetings from Panama,

The upper and lower bearing support the steering knuckle and allow it to turn. Both bearing forces are working together. If one bearing is loose, the other will be loose as they are opposing each other. So if you add one shim, the free-play that is removed will be removed from both bearings.
Yes it is true that by adding shims to either the top or bottom will shift the centerline of the knuckle in relationship to the axle housing, but unless you were adding a mm of shims, the offset is insignificant. The only issue I can see looking at the drawings is the relation of the axle to the oil seal. If the offset is too severe, the oil seal could leak.

jayj wrote: Greetings from Panama,
The only issue I can see looking at the drawings is the relation of the axle to the oil seal. If the offset is too severe, the oil seal could leak.

Most suppliers of lip seals will allow quite a lot of offset as long as there is no throw. A shaft seal should easily cope with an offset of 0.2mm without it being a leak problem. Most seals should manage 0.4mm offset depending on the profile and design.

Especially if you fix the wooble and vibrations by adding a shim the seal will be more comfy

The reason for me reading old shim threads is that I am going to my garage to shim up my lower shims just as an quick fix before driving tonight to and from a music festival. I will do it properly later and change the bearings and all as a complete service, but driving yesterday I got fed up with the wobble.
So I am trying to find a tip i saw earlier on just adding shims to the lower pins as a test.. but i couldn't find it, or how much to add so I'll just "gefuhl" it.