When the flange is torqued up it will stay in whatever position it’s set to, it won’t be using the bolts in sheer to prevent rotation. The friction in the clamped joint is what resists the torque and the stretch in the bolt from the correct torque is what keeps the clamping force there. Therefore the thicker bolt will only be to set the castor more accurately on initial tightening. You could instead get the 7 identical bolts almost tight and set it to the middle of the range you can clock the housing to for the same effect or use the old bolt to locate, torque the others and then replace the old with a new normal one if you wanted (though that would mean the next people doing it probubly wouldn’t know a bolt was meant to be different). Does it matter? It will effect caster slightly (depends how big the holes and the PCD are) but probably less than what a lot of people do when lifting their suspension (which admittedly is often enough to ruin the handling without castor correction) so it may be that being able to use normal bolts and clock it a bit more could be an advantage depending what castor you actually have and if you balance both sides. The book figure is meant to be 3 degrees and LR claim it’s not adjustable (ie doesn’t need to be adjusted on a standard vehicle). If your truck is stock it’s probubly best to keep all these little settings stock as dispite what people seem to think about Land Rover engineering, there is a lot of research and testing that goes into little details like this to achieve the best compromise for a standard vehicle in normal use conditions - generally speaking a lot more testing than aftermarket component makers ever do on their ‘upgrades’. Would be interesting to know how much rotation can be achieved there as that would show how much effect it would have.
Defender 110 front springs are about 200 lb/in and rears are about 300 lb/in. Assuming even distribution, a Defender loaded to 1000 lb or 500 kg will sit 1" lower, and fully loaded to 1000 kg will sit 2" lower than when empty. In reality, the load will almost certainly be biased towards the rear. The 'standard' castor must be a range, not a single figure. I would guess a 2" lift kit could put the castor outside that range, but I doubt the hole tolerance would. I've carried a stack of 8' railway sleepers with 2' sticking out the back door. Well within legal axle weights, but it made the handling a bit odd. 🙂
Looks like Rimmer Brothers supply different bolts (well different bolts are pictured) for UYG500040 and UYG500050 (one has pink lthread locker, the other blue), and UYG500040 is over a fiver per bolt
It's not unusual to have one dowel bolt to locate something. It would be alot easier though if they drilled one hole smaller instead. It would do the same job and be impossible to get wrong.
Yes indeed. I have bought those two king bolts from two different well-known suppliers and just ended up with another two standard bolts, all around the 9.8mm range. Waste of time & money.
Are the aftermarket fat bolts actually 10.5 mm or only 9.8mm? I bought genuine when I did mine, as I did not trust aftermarket on something this critical
Only a thought... Are the location bolts in a different position on either side of the vehicle? Thought it might be to prevent inadvertent swapping of the housings side to side?
It would have been useful for LR to supply bags of a kit for a swivel housing, ie a bag with six plain and one shouldered bolt per bag. This goes beyond ease for customers - it’s a safety issue.
When the flange is torqued up it will stay in whatever position it’s set to, it won’t be using the bolts in sheer to prevent rotation. The friction in the clamped joint is what resists the torque and the stretch in the bolt from the correct torque is what keeps the clamping force there. Therefore the thicker bolt will only be to set the castor more accurately on initial tightening. You could instead get the 7 identical bolts almost tight and set it to the middle of the range you can clock the housing to for the same effect or use the old bolt to locate, torque the others and then replace the old with a new normal one if you wanted (though that would mean the next people doing it probubly wouldn’t know a bolt was meant to be different).
Does it matter? It will effect caster slightly (depends how big the holes and the PCD are) but probably less than what a lot of people do when lifting their suspension (which admittedly is often enough to ruin the handling without castor correction) so it may be that being able to use normal bolts and clock it a bit more could be an advantage depending what castor you actually have and if you balance both sides. The book figure is meant to be 3 degrees and LR claim it’s not adjustable (ie doesn’t need to be adjusted on a standard vehicle). If your truck is stock it’s probubly best to keep all these little settings stock as dispite what people seem to think about Land Rover engineering, there is a lot of research and testing that goes into little details like this to achieve the best compromise for a standard vehicle in normal use conditions - generally speaking a lot more testing than aftermarket component makers ever do on their ‘upgrades’. Would be interesting to know how much rotation can be achieved there as that would show how much effect it would have.
Defender 110 front springs are about 200 lb/in and rears are about 300 lb/in. Assuming even distribution, a Defender loaded to 1000 lb or 500 kg will sit 1" lower, and fully loaded to 1000 kg will sit 2" lower than when empty. In reality, the load will almost certainly be biased towards the rear.
The 'standard' castor must be a range, not a single figure. I would guess a 2" lift kit could put the castor outside that range, but I doubt the hole tolerance would.
I've carried a stack of 8' railway sleepers with 2' sticking out the back door. Well within legal axle weights, but it made the handling a bit odd. 🙂
Looks like Rimmer Brothers supply different bolts (well different bolts are pictured) for UYG500040 and UYG500050 (one has pink lthread locker, the other blue), and UYG500040 is over a fiver per bolt
It's not unusual to have one dowel bolt to locate something. It would be alot easier though if they drilled one hole smaller instead. It would do the same job and be impossible to get wrong.
Same problem here, and same solution - after a lot of back and forth with the retailer who didn't care and wouldn't refund because I'd opened the bag.
I've found exactly the same, ordered both but ended up with the same diameter 9.8/9.9 bolts. I spent ages with a micrometer checking these out.
Thanks so much for the invaluable info I was just today going through the same thing today
Yes indeed. I have bought those two king bolts from two different well-known suppliers and just ended up with another two standard bolts, all around the 9.8mm range. Waste of time & money.
This is the reason why I subscribed to you...
Will the fatter bolt not fit in the other holes?
I don't have one apart to play.
Are the aftermarket fat bolts actually 10.5 mm or only 9.8mm? I bought genuine when I did mine, as I did not trust aftermarket on something this critical
Only a thought... Are the location bolts in a different position on either side of the vehicle? Thought it might be to prevent inadvertent swapping of the housings side to side?
When i did mine on a 2006 defender they were hex head from the factory not torx type like these
New ones were torx type
Good day Will, I have some questions for you as you own a 2.8TGV and I am also looking into buying one too. How can I contact you?
It would have been useful for LR to supply bags of a kit for a swivel housing, ie a bag with six plain and one shouldered bolt per bag. This goes beyond ease for customers - it’s a safety issue.
I didn’t even realise 😳
ive done loads of these never ever used the fatter bolt and not had a single issue