What did you do to your jimny today?

wrote:

Suzuki presumably designed for a specific axial preload force and built in enough preload to achieve that force. Modern machining tolerances are pretty close. Say they can achieve an accuracy of +/-0.05mm, which is pretty sloppy by modern standards. That's only 10% of the preload. In that case there is no point adding the costly step of installing shims and checking t"he preload.

"Presumably", "pretty close", "pretty sloppy", "no point". Engineers don't work like that.

Roger


 

wrote:

100% correct, Les, in production you would never assemble something, measure and then take apart and add shims, it would take far too long and needs a few bins of shims of different sizes, that might run out at any time. If it needed factory adjustment, they would make an easier method of doing it.

If they don't do it in production then they are unlikely to do it on a service, they would just say the hub or bearings are out of tolerance and say you need a new one.

Robin

There are many instances in car production where tolerances are known  and must be checked to ensure proper working of the unit involved. Yes there are instances where other methods have been adopted, crush tubes on the pinion shaft of a diff. for example, but as Martin supplies shims to alter the pre-load on the king pins then I would suggest, especially as by doing so, "death wobble" is eliminated or at least reduced, then they have a purpose. I will not apologise for being pedantic but I was taught that if a job was worth doing, then do it well.
When I was trialling, we Suzuki boys would laugh at the attitude of the Land/Rover boys because their doctrine was "Oh it will be ok". Famous last words.

Roger
 

I don't disagree that a shim has a purpose, I have used shims myself in other situations, it's just a not production method anyone employs anymore for the reasons set out above.

Mind if you have a Ducati Desmo [Desmodromic Valves, a cam and lever to open the valve and another to close it) motorbike with Bevel head you will know all about shims, they used them in production to set valve clearances among other uses as it was the only way it could work. The bevel heads are amazingly difficult to set up correctly as a result.

Robin

Try to assemble a differential without shims and preloads.

This kind of discussion is pointless and as no one else seems to be interested in joining in I will bow out and let those who wanted the information store it for future use.

Roger

Would not something like an axle be a subassembly built on a separate line if not by a separate manufacturer. It would have to meet tolerance but being a subassembly would have less impact on final installation time so could be set correctly. I say that because at full chat with everything clean and to hand I can assemble a knuckle onto an axle tube in about 25 minutes, obviously in a jig in a factory doing it hundreds of times a week I would get faster still but that's never going to be quite quickly enough for a production line for cars. Dunno, it just seems logical that even with production machining there could be room for adjusting the tolerance to spec at assembly?

Changed the parking light "bulb" that was blinking cause it is a cheap chinese ebay LED.
But before that i was in a garden lawn where a Vivaro Electric van had sunk into the ground in the thaw and it has rained for days now.
Wife knows I love a bit of rescue so she tipped them of me when she heard they got stuck.

4-low, locked rear diff, cheap snatch strap and several yankings later I had to lower tire pressure in the rear wheels to 0.5 bar and then I got it out.
Loved it even in the pouring rain