[CaptainLeo]

Hey all, I could use some help.

Recently installed a 3" spring lift. Now my rear diff is pointing up towards the T-case, and the t-case is still horizontal like normal. This is resulting in some bad vibrations and shitty uni-joint angles. Does anyone know how to adjust the angle of the rear diff so that it points horizontal also? As far as I understand from all the reading I've done, the t-case and diff need to both be horizontal within a few degrees of each other in order for the uni joints to work at their best.

Any help would be greatly appreciated.

[shandy92]

What lift kit did u get? Come with a rear a-frame spacer? If not, it would help.

[CaptainLeo]

Not a complete kit, I bought parts individually. Coils second hand off gumtree, shocks gumtree (unused), struts ebay. Had a mate fab up driveshaft and a-frame spacers, which are all in. Diff still wants to point upwards.

[Gwagensteve]

I reckon there's two problems here.

One is the A arm spacer. It needs to be offset to keep the pinion angle correct. (I also think you'll find the design of that spacer will result in broken bolts- this has been proven before)

The second is the driveshaft spacer(s) do they have the spigot machined into them to accurately locate the driveshaft? The driveshaft isn't intended to be accurately located by the bolts, it centres on the spigot machined into the pinion flange. If your spacers don't have the spigot, you'll have driveshaft vibrations for sure.

Steve.

[Gwagensteve]

Here's a photo of an A arm spacer I made up some time ago for a vitara.

Obviously the top plate isn't fitted in this photo, but you can see the amount of offset required to maintain pinion angle .

[CaptainLeo]

So the A-arm needs to be offset (have a certain degree of angle to it) in order to align the diff properly? I'll see if the guy who machined them can add some angle to align the diff properly.

These are the single tail shaft spacers that I got machined:



Is the centre whole the spigot you mentioned? They were all machined at the same time with the same dimensions.

[Gwagensteve]

Thats what I feared.

Have a look at this.



See how there is a raised ring on the inside edge? This is what locates the driveshaft, not the bolts. There's a corresponding rebate in the other side of the spacer to lock that into the driveshaft. The bolt holes are, in fact, slightly oversized to speed assembly, they only provide clamping force to hold everything together. Your spacers don't have this boss so the driveshaft can't align properly.

Here's another view. (this is the reverse of a sierra, but the theory is the same)



I know not having the locating spigot causes vibrations because it happened to be when I tried adapting 1.0 yokes to 1.3 flanges without a spigot spacer.

[CaptainLeo]

So that raised ring on the inside edge, does that have to be on all of the 10mm spacers I've used? Or just on the one directly contacting the driveshaft? The holes for the bolts in my spacers aren't oversized like you mentioned, the spacers were machined for the specific size bolts I had. Not sure if that'd make a difference?

[Gwagensteve]

No, the holes in the flanges are oversized because the bolts don't locate the driveshaft. the bolt holes in the flange and driveshaft are 10.7mm, to fit 10mm bolts.
Yes, the raised ring must be on all the spacers, although in truth stacking spacers isn't a very good idea at all and should be avoided.

[CaptainLeo]

I agree that stacking spacers isn't a good idea, however I had no idea how much spacing id need, and it was cheap enough to make these even as a temporary measure.

So in regards to the rear A-arm spacer: could I theoretically cut a small angle out of the bottom half of the spacer to adjust the pitch of the diff?

[Gwagensteve]

No, because the bolts will still be parallel to the mounting surface.

The amount of spacing you require will change again once you get the pinion angle right, and you'll need to fully cycle the suspension without the springs in to confirm you aren't able to bottom out the slip yoke on full compression.

[CaptainLeo]

OK, well looks like I'm gonna have to go back to my machining friend and see if he can make me up some new stuff given this new information, cheers dude

[Gwagensteve]

In all honesty, all this stuff is really just a sign you have too much lift. You're impeding the ability of your suspension to work properly, and you've dramatically shortened driveline life.

[CaptainLeo]

With all due respect, I fail to see how the amount of lift I have is going to dramatically shorten driveline life. So long as the supporting mods to the suspension (spacers etc) ensure that the driveline is operating and functioning as designed, I don't see an issue. Sure, there will be some aspects of the vehicle that will be weakened or at higher risk of damage because that comes with the territory of lifting a vehicle. However 3" is still quite common and very manageable given my research. There are people running 3" coils in addition to spring spacers, which is downright ridiculous. So long as the effort is made to ensure all the aspects of the vehicles suspension are operating close to their intended design there isn't much of an issue.

I am thankful for your advice and respect your opinion.

[Gwagensteve]

The front CV angles are excessive dramatically reducing CV life. The 3" springs will be topping out the struts, shortening their life. The steep tie rod angles place excessive load on the drag link and especially the idler arm, which results in a very short life and/or bending. Rear uni angles are excessive on a SWB vitara with 3" of lift, and yours will only get worse once you correct the pinion angle. the rear slip yoke needs to be excessively extended to accommodate the full range of suspension motion, which worsens the uni angles. The rear A arm spacer raises the rear roll centre, negatively affecting roll axis and handling. The RHF axle tends to pull out of the diff centre with 3" springs necessitating the "tripod" CV mod to ensure durability.

Despite not owning a Vitara myself, I have PLENTY of experience working on 3" lifted Vitaras. I think I've worked on four or five. They aren't very reliable at that height without significant investment and problem solving. Many people give up without ever really getting the bugs out. With any IFS design, the flatter the CV angles at rest the more reliable the car. In fact, I would run diff drop brackets on a standard to 2" lift height vitara for that reason.

Been involved in a bit of custom Vitara work over the years. I don't think I'd be chasing "big lift"

[got_bar_work]

After owing a 3in lift vitara i would be moving the chassis end of both down. Would suck for ground clearence but it would dive way better. I havent ran the numbers on a link calculator but i recon they would be bad. I would also be trying like a 18in 2.5" coil with around 100lbs. 20"-24" coil if i could find one soft enough . After doing a lot of reading on pirate i now realize how bad all the off the shelf spring manufacturers are in australia. All the rates are crazy high and the free lengths are way to short.

[Gwagensteve]

Yeah, I've seen a few of these Z notched builds, and I guess it does raise the chassis in the ramp over area, but otherwise it offers little advantage and will never, ever be legal (or reversible) here.