Rear Leaf Spring Upgrade

Does your Mitsubishi L300 make a strange noise? Need wheel alignment specs?
kyre
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Rear Leaf Spring Upgrade

Postby kyre » Mon Jun 18, 2018 4:41 pm

My rear leaf springs are pretty tired and flat and am looking for options to bring them back to life or purchase new.

I got very different quotes by 2 local spring shops. One was around $800 to just re-arch and the other was about $500 to re-arch and add a leaf. The issue I've been reading is that a re-arch won't last and they'll be flat again in a few thousand km or so.

Has anyone fitted Dobinsons rear leaf springs MIT-018-R ? I just got a quote from the US distributer $864 for the springs, $90 for bushing kit, $50 u-bolt kit, and $60 for shackles. Nevermind the cost to ship from Australia to California (they didnt say yet). They mentioned it's a 35mm lift.

Does anyone have experience with this kit? I haven't found much info about anyone with experience using them. It's a lot of money so just figuring my options.

Any other springs from another vehicle that could be retrofitted?

The 2 cheaper options would be to fit air shocks in the rear or buy a shackle lift/ball joint spacer kit but I'll still have tired old springs.

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Growlerbearnz
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Rear Leaf Spring Upgrade

Postby Growlerbearnz » Mon Jun 18, 2018 4:57 pm

There's recently been a bit of talk about leaf springs.

Before I settled on air shocks, I tried installing an add-a-leaf (viewtopic.php?f=10&t=18521&p=137959). Result? Slightly too much lift, difficult to align the gearbox and differential. Super smooth ride though.

Cosmo727 has re-arched springs, but they've also added an arch to the lower overload leaf. Don't do that. viewtopic.php?f=6&t=18850&p=138750

Stock ride height measurements: viewtopic.php?f=6&t=18846&p=138720 ...but basically, the spring pack shouldn't be resting on the lowest overload leaf, there should be a few millimetres between the spring pack and overload.

I ended up liking the air shocks because they're adjustable for load, unlike a heavy re-arch which sits high when unloaded, and drops when loaded.
Nothing says "poor workmanship" more than wrinkles in the duct tape.

kyre
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Rear Leaf Spring Upgrade

Postby kyre » Mon Jun 18, 2018 6:18 pm

I read your posts Growlerbearnz, which is why I'm skeptical to add a leaf.

I need to lift the rear of my van and measure the unloaded camber in the rear springs. I'm thinking those Dobinsons would be nice but I need new tires too and I just can't drop that much cash right now.

Once I know the camber I should know how flat these really are.

It sounds like you really like the airshocks and the price is definitely right. Do they actually lift the van a little if my springs are tired? Is that a lot of strain on the mounting points?

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Growlerbearnz
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Rear Leaf Spring Upgrade

Postby Growlerbearnz » Tue Jun 19, 2018 2:32 pm

They do lift the back slightly (more depending on how much pressure you put in them). On my van 30psi was enough to lift it about half an inch, back to where it should be, with the spring pack clear of the overload leaf. The ride is *much* smoother.

30psi adds a load of 150lb/70kg to the shock mounts, and they're built strong enough to handle an offroad hammering. So far I've had no issues, even with them pumped up to 70psi to level the van up when towing the caravan. I would think the rubber bushes would fail before the shock mounts do, and they still seem to be in good condition.

Ideally I would (and still might) have my springs re-set to factory, and keep the air shocks to take some of the load. (I suspect that the springs wouldn't sag with the air shocks helping). But even without touching the springs, the air shocks are a quick and cheap way to fix rear-end sag.

I haven't seen anyone who used the Dobinsons springs yet. My concern would be the ride height increase, if it's not what you want then you're stuck with it- but plenty of people are driving lifted L300s and just live with the driveline angle issues, or just don't notice, or don't put enough miles on their vans for it to be a problem! ;-).
Nothing says "poor workmanship" more than wrinkles in the duct tape.

kyre
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Rear Leaf Spring Upgrade

Postby kyre » Tue Jun 19, 2018 5:48 pm

Thanks again for your clear explanation of things Growlerbearnz.

I think I'll try the air shocks out, especially for that price. I just can't afford the trial and error of buying those Dobinsons right now. This will also allow me to afford those 24mm H100 Torsion bars you mentioned in another post.

Will post back with my experience once I purchase and install.

Mr.SA
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Rear Leaf Spring Upgrade

Postby Mr.SA » Thu Jun 21, 2018 12:29 pm

I just finished installing new rear leafs last weekend. My stock ones were so worn out i actually had a bit of negative arch :shock: I got mine custom made from Alcan spring in Grand Junction CO. Ive only put maybe 50 miles on them, but so far im really impressed. Its 6 thinner leafs vs the stock 3+overload. so its smoother initially and ramps up a bit more. Still has that truck like feel, but its a big improvement over stock. leafs and u bolts shipped cost me around 725.

Ive got a bit more weight in the back of mine with a rear bumper and camper setup, probably what killed the old leafs. so my spring pack probably wouldnt work well with a stock delica. but if you call them up and give them your weight i'm sure they could get it right. they just built mine so im sure they'll have my info and measurements to go off.

They dont use that big oval bushing in the front. its just a regular smaller circular bushing. that was the only thing that took some cutting to get to fit well. removing my old ones was a huge pain.


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