sj spring conversion need help

[slimady121]

hi im trying to do a spring onversion on my truck but dont know the best way of fitting the rear axles

[Anton]

Looks to me like you're copying a Jimny setup on the front. You could copy the Jimny on the rear too, or there's always the option of using Vitara trailing arms and upper wishbone.

There was a guy once who rolled a complete Vitara rear axle under an SJ, and the trailing arms bolted right up to the spring hangers in place of the leaf springs, located the axle exactly right too! He just welded in a crossmember for the upper wishbone and he was done.

You could probably make the same thing work for you. It's what I'd do if I were to coil my SJ (which I've dreamed about many a time).

[slimady121]

cheers for you help iv seen this done for the rear

[d_r_1989]

as anton says the vitara trailing arms almost line up to the original leaf spring mounts, then you just need a bar welded in to bolt the vitaras rear "a frame" to. I reckon it's not too bad a job.

Saying that! I can't see any mounting points on the axle for the vitara trailing arms. If I were you I'd buy or make some mounts to weld on to the axle and utilise either jimny or rangerover arms, make some mounting points on chassis and get more flex from them. The longer the arms the more flex.

[ScottieJ]

Don't do a 1 link like in that 2nd picture, to get them to work well it's not easy and to be honest it's the most redneck link set up there is.

Also the Panhard rod on your front axle is the wrong way around, it needs to mount to the axle on the passenger side and the chassis on the driver side, it needs to be as close to the same angle and length as possible to the drag link from the steering box or you will get bad bump steer.

Is this SJ for off-road use only? If you want to use it on road it will need to have an IVA test when converted to coils.

[Anton]

Is this SJ for off-road use only? If you want to use it on road it will need to have an IVA test when converted to coils.

If it does, then you'll probably find that technically so does SPOA. I can't find a definitive answer on this from the DVLA website though, I've never seen anything that says converting from SPUA to SPOA or converting from leaves to coils requires IVA. Not saying you're wrong, just that I have a sneaking suspicion that you could get it inspected under the 8 point system.

I've heard a lot of people say it needs IVA, but I can't find an official yay or nay anywhere.

[ScottieJ]

For SPOA you are not changing anything on the chassis.

For coils you have to modify the chassis a lot, and you are also making a major change that could effect the handling of the vehicle, I've seen some death trap coil conversions. Give VOSA a call, I'm pretty sure they will tell you that it would, the 8 point system does not always apply when it comes to an IVA. Look at rangerover bobtails, you aren't really changing anything that could alter how the vehicle drives yet it needs an IVA just because you have chopped a bit of chassis off. Converting from leafs to could is a major change compared to that.

At the end of the day though there are 1000s of cars on the road that probably should have had an IVA, if you ever get caught out I doubt you would loose he vehicle completely, it would probably just be taken off the road. Is it much of a risk, probably not but its worth thinking about.

[Anton]

Yeah, I've been thinking about a coil conversion for a long time, but I decided a while ago that it'd be better to just get a Jimny.

I do think that if you can make a bolt-on rear setup like the Vitara rear, you wouldn't need to IVA it. Adding a crossmember is ok, adding or shortening the chassis is where you lose the 5 points. I take your point about it being dangerous, but there's also plenty of SPOA deathtraps out there.

Technically *any* modification to the suspension, steering or drivetrain does require a V627/1 form (built up vehicle report) and an 8 point inspection. "Radically altered vehicles are vehicles that have been altered from their original specification, but aren’t kit conversions." (VOSA's definition, not mine). Every lifted or slammed vehicle in the country legally should have one, but VOSA doesn't seem to make a fuss if you're not stupid about it. I think essentially they trust the MOT centres to report anything that looks like it would end in death.

Where they get funny about it (according to their website) is if you don't comply with the vehicle regulations found here:

http://www.legislation.gov.uk/uksi/1986 ... tents/made

At least, this is what their website seems to say:

https://www.gov.uk/vehicle-registration ... d-vehicles

The idea of coiling an SJ still tickles my brain though. I'd love to do mine, the challenge of making it work right whist still complying with the letter of the law (and making it safely) just appeals to my inner nerd *so* much!

[slimady121]

as the rear axle has the diff in the centre and an sj diff is off set will it still fit and woul i need a different prop ? thanks

[Anton]

That looks like a Vitara rear to me. You might want a longer prop or spacers, it's difficult to say without knowing how high the vehicle is going to end up.

Pretty sure that the Vit axle swap I was talking about used the standard prop, but since its not on Google, it's hard to remember.