So, after a leaf spring breakage, all the leaf springs were replaced and one extra was added to the pack because, as a camper, you never drive around “empty”. There’s always a basic payload due to the interior. The new leaf springs lifted the rear, so the front suspension was improved too by replacing the standard torsion bars with heavier ones and a ball joint spacer was added to match the rear lift. Last but not least, the factory shock absorbers were replaced with Koni Heavy Tracks. Especially the improvements on the front end are a big improvement in comfort.
About the torsion bars:
I replaced the front torsion bars with the torsion bars of a Hyundai H100 2wd. The Hyundai has bars with a diameter of 24mm and is therefore just a bit stiffer. I believe the original Mitsubishi ones were 20mm in diameter (delivery van. Other versions could have 22mm).
The H100 is technically much the same as the L300. On this page, the L300 wiki,
you can see that there are more variants of the van that are technically (almost) the same.
However, there are minor differences… the L300 is still from the “build in Japan” era and you can see that in the details: where the L300 has dust caps around the bar index ends, the H100 does not have such protection. I re-used the dust caps from the L300 and I did the same with the tension arms at the back.
About the ball joint spacer:
To match the lift of the rear, I placed a ball joint in the upper front suspension arm. The advantage of this is that the geometry of the wishbones almost does not change but it does provide some extra ground clearance. I have used a spacer of 20mm. The van has been raised in total about 40mm. Note that it is not wise to unlimited tighten the torsion bars to increase clearance. If the gap above the bump stop is too small, the suspension cannot extend enough. Driving through a hole could then mean that the bump stop too soon limits wheel travel and reduces the ability for the wheel to follow the road surface. No contact with the road means no control of direction.
Before changing, measure a few fixed sizes (between the wheel arch and rim edge, for example) and also at the nuts of the torsion bars, so that you have a guideline value after the exchange. Also make marks between bar and holders. The bars also have left / right and direction of rotation markings. Pay attention there too.
After exchanging the parts, the van must be realigned, and it must also “settle” after the exchange. I did it like this: I put 4 pieces of hardboard under the front wheels, two under each wheel with the smooth sides together. This reduces friction so much that you can easily adjust the torsion bars to the correct driving height (with the full weight of the van). Then drive a bit, and again park it with the front wheels on the hardboard plates and check. Then align or have it aligned.
Castor : 3° ±1°
Toe in : on the rim 0 – 3 mm
On the tyre: 1 ±3 mm
Camber : 0° 30′ ± 45′