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henlan77
29th May 2008, 09:34 PM
Hi guys,

I have a heavy duty box trailer that I take onto some steep and fairly rough building sites behind my 4WD.

I would like some more clearance under the box trailer for passing obstacles and avoiding dragging the tail on steep gullies etc. The towball on the truck is also a fair bit higher than the trailer so it drives a bit 'nose-up'.

I was thinking of moving the axle from on top of the leaf springs to below the springs. I believe it is called a spring-over conversion in the 4WD world.

Looks like a very simple process - just remove the wheels, remove the 4 U-bolts, flip axle over and reassemble.

Is there any saftey or rego issues I haven't considered?

Thanks in advance.

Claw Hama
29th May 2008, 09:38 PM
Been there done that had no problems.

henlan77
29th May 2008, 10:23 PM
I read that some trailer axles have camber or castor or whatever built in. Is my garden variety trailer likely to have this and can I stuff it up by flipping the axle?

Now I am wondering... should I flip the axle 180 degrees, or keep it in the same orientation and just drop it below the springs?

Cheers.

Claw Hama
29th May 2008, 10:28 PM
You would be very lucky if it is straight let alone have camber built in.

Dusty Dave
29th May 2008, 10:53 PM
Just swapping spring-under for spring-over is cheap but it will only buy you a couple of inches.

Maybe think about replacing the hubs too so they take the same rims as your 4WD (you can find 6-stud trailer hubs in Supercheap for not much), then pick up a couple of steel rims to suit from a wrecker. Bigger wheels will make a much bigger difference off road, and being able to interchange your spares is a real bonus.

Personally I'd probably replace the springs with some higher, heavier ones while I was at it - they aren't particularly expensive.

dazzler
29th May 2008, 11:00 PM
Hey

No worries with putting the axle under the springs. Just remember that there is a small axle pad with a hole in the middle that is welded to the axle that the spring bolt (holds spring together in middle) head locates in to locate the axle. You may have to remove this bolt and turn it around so its round head fits the pad. If so you will need to clamp the springs together before you remove the bolt.

Camber or castor is not an issue in a trailer as the car effectively tells it where to go.

Buzzer
30th May 2008, 05:00 AM
If it were me Iwould swap the axle as said before. The extra couple of inches should make enough difference for good clearance.

The bolt that dazzler is talking about is called a center bolt and may have to be replaced with a new one as they have a habit of seizing up over time.

weisyboy
30th May 2008, 08:15 AM
just remember you wil gain no clarance under the axle by doing this it wil stay the same distance from the ground. otherwise there will be no pronblems.:2tsup:

henlan77
30th May 2008, 09:17 AM
Thanks for the info everyone. Will give it a go this weekend.

Yonnee
30th May 2008, 06:55 PM
Camber is only put into caravan axles that are on their upper weight limit. It helps a little with tyre wear.

The centre pin/bolt through the springs will be your only hiccup. The head of the bolt is at the top of the spring, so putting the axle underneath, the 'spring pad' (the little square spacer usually welded to your axle) wont be thick enough to clear the thread of this bolt. You can either shorten the thread with the grinder, or clamp the spring, remove the bolt and poke it through from the bottom.

Easy enough to do otherwise and will gain you more than some think. Even with only 4lf springs you'll go up 3", and that's a fair bit of extra departure angle.

Yonnee.