When to change torsion bars and leaf springs

Hi everyone

I've recently acquired my first Hi-Ace. Hurrah! 1993, 2.8 3L, LH-129, part-time 4WD.

I like it, but it wallows like a hippo corners and bounces like a pogo stick over uneven ground . I know this van was not built to be a racing snake but my gut feeling is that it's time to bite the bullet and start replacing stuff. 93,000 miles, 24 years old after all.

I'm starting with replacing all of the anti-roll bar rubber this weekend. Cheap-ish and easy DIY. Visually frayed but not completely shot - seen worse. By the way, does anyone have torque values for this? My plan is finger tight, lower onto ground, bounce, then tighten, as per previous vehicles with similar set-ups, but I can't find a torque figure for anti-roll bar link nuts etc once on the ground in the pdf workshop manuals I have scratched together. Anyone know?

So my question is - if the new anti-roll bar rubber doesn't miraculously transform the handling, where would you guys go next -

1 - Shocks (also cheap-ish from Toyota, no visual leaks on mine at present, but I suppose they could still be tired)?
Or
2 - Torsion bars and leaf springs (not cheap at all, so wouldn't want to change these and find no change...)?

I don't have the data for proper measurements, but looking at the van from the side, the ride height is symmetrical and equal all round, and (based on gut feeling only, wheel arch gaps etc) it doesn't look like it's obviously sagging to me.

I've never had a vehicle with either torsion bars or leaf springs before. Presumably, like any design of spring, the metal eventually loses it's memory and they need replacing. Obviously it will vary vastly on terrain and driving style, but my last question is -

3 - Has anyone got any advice on how many miles or years they're intended to last, on average?

Many thanks for you help
Niel

I'll be doing similar soon to me 2.4 Super Custom, plan is to replace anti roll bar rubbers and links, fit gas/uprated shocks all round then lower the rear with custom made lowered and stiffened coil springs and wind of the front torsion bar nut some more, already wound it off about 20mm on thread to drop the front a bit, downside to this is I'm taking tension out so it make it more wallowy so I'm looking at different manufactures shocks namely VW T4 gas shocks as they should fit given a little fettling

I suspect wallowing and bouncing can only be shocks TBH.
There was a manual download on this site that may have torque figures, else the Hilux one may have a similar under-pinning.

Thanks for the replies.
I agree - my money is on the shocks being the most likely culprit.
Does anyone have an opinion on when torsion bars and leaf springs should be replaced as a matter of routine? Or do people just run them until they break?!
Niel

If they get too rusty or break I guess, I'm not such an expert on spring life except to know that macpherson struts (on the front of lots of cars) break when the top bearing starts getting stiff, and I did have a coil break off on the back of an old car due to age so new springs certainly wouldn't hurt, assuming the job was easy and didn't disturb too much of the rest of the car.

I did discover you had to unload the front of the van to turn the torsion bar adjusters though - they are a bit stiff with the full weight on them.

Leaf springs can look brown and rusty while still operating fine. Normally they don't break, unless you drive over a big hole with a lot of speed. But then even new ones can break.
What I did is bring the leaf suspension to a company which "hammers" it back into shape, and I had a spring added. But this was all because I wanted to get it raised. I think it was a bit lower after 23 years.
Replacing them is too much I think.

With the torsion bars there can be a bit of wear as well, making the van sit lower then original.
You can wind them up if you want, to make it higher and stiffer (you can't choose)
They can break, but the chance is small. I've heard of these occasions with older 4x4 cars (not vans) used to the limit.
I have been thinking about it as well, and I don't think I will replace them. I have same mileage and age roughly.

About the lifespan: One guy said to me he drove one of these vans for his job, it had 800.000 kilometers on it.
Most of the old vans in the export market have around 400.000 kilometers on them.

The engines may sometimes need an "annoying" repair, like a radiator replacement (not so easy as with a normal car so more cost) or a leaking seal somewhere, but you can just fix that and they are very reliable.
I think rust is the only real enemy here.

Thanks for the thoughtful replies guys

The new anti-roll bar rubbers have definitely improved things a bit on the corners, but it still wallows on corners.

It sounds like replacing the shocks is probably a good idea (looks pretty straightforward too), but new leaf springs and torsion bars would be overkill.

Hiace4WD - could you tell me the name of the company that hammered your leaf springs back into shape?

Best wishes and thanks again

Niel

It is in the Netherlands, called Eeltink Veertechniek. I guess you chould ship the leafs there and all, but I would think that you would find one or more of such companies in the UK.
I went there because they can also make an extra leaf to the specification that is needed.

If you don't wish to make the van higher, I would leave it as it is.

It is safe to assume that the vans with the high mileage on them never had any leaf suspension or torsion bars replaced, that would already be too expensive I think. At least for the users who want to get the most (mileage) out of their old van for business use.