Toyota Tundra Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
29 Posts
Discussion Starter #1
1 1/4" Suspension Raise on 04 Highlander (Kluger)

As a few of you will know, the Toyota Highlander (Kluger) – mine is a 2004 V6 AWD – is surprisingly capable off-road. It can tackle tracks much worse than logging roads, but certainly not as extreme as the Rubicon Trail! The main limitation and concern is the limited ground clearance, particularly at the plastic fuel tank, where it is about 7”, and where the standard plastic/metal shield under the tank is intended only for protection from small flying pebbles. The clearances further forward are actually not that bad, and in general the Macpherson strut suspension front and rear provides better real ground clearance than most other suspension types. The exhaust pipe towards the rear could do with more clearance but the risk of bashing the exhaust is much less of a worry than putting a hole in the fuel tank, whilst likely many miles from help.
I like the Highlander, it does almost everything very well, gets good fuel mileage, is very comfortable for long distance driving, handles well, it’s easy to park, and, not least, my wife is comfortable driving it. Therefore, I was more inclined to tackle the poor ground clearance, than I was to trade to a more truck like vehicle with more clearance, even if money was not a factor. Also, as the vehicle is now about 6.5 years old, out of warranty, yet still in excellent shape with hundreds of thousands of miles of life left in it, I felt that this was a good time to tackle some moderate modifications to address the limited ground clearance.

I soon discovered that Macpherson strut suspensions do not lend themselves to modifications. I could not find any serious lift kits on the market in north america, or internationally in places like Australia. This was not surprising really, as most buyers with known interest in off-road travel would likely have bought a 4Runner or equivalent in the first place. In my case, back in 2003, my wife was transferring from a small car and was very concerned about handling a bigger vehicle, and she was concerned about fuel consumption. Therefore, although I would have preferred to have got a 4Runner, I knew that the Highlander was the better choice for the family, more comfortable, equally spacious, got better mileage, and it was still well up to our frequent yet moderate towing needs (max 3500lbs).
In the absence of market kits or help, I set about developing various lift designs that would work without significant disadvantageous trade-offs and which would be economically installable. My final chosen scheme provides 0.50” suspension lift + 0.45” tire radius lift + approx. 0.30” tire wall extra stiffness lift, for total of 1.25” – not a great deal, but worthwhile, and I anticipated (correctly) minimal re-alignment difficulties or handling problems. The extra clearance would allow me room to install later a robust ¼” plate fuel tank guard in phase 2. The extra lift would make the Highlander ground clearances quite similar to or better than a number of other more off-road geared vehicles, for example the 4Runner, according to my underbody measurements of a 2004 4runner.

Tools: If you do not have access to a metal cutting swing down arm bandsaw ($250 for a portable) and to a drill press, read no further, both receive extensive use or are indispensable to the manufacture of the parts required.

The major advantage of limiting the suspension lift to 1/2” is that it allows use of the existing 1” projecting top of strut anchoring studs to retain the new ½” shims. I decided to make all the shims out of stainless 304 bar 1.5” x ½”. I already owned a 4” portable bandsaw, and I purchased some high quality Sandvik Cobra 10-14tpi blades to make the many cuts in the hard stainless steel required to shape the shims. My design was based on inserting the shims through the holes in the top of the strut turrets after lowering the struts by about one inch. On the attached rough sketches, you can see the shape and arrangement of the ½” thick shims which I designed.
Installation went well. At the rear, after disconnecting the sway bar (use an Allen key to hold the bolt), I found that the strut still would not lower enough. I had to re-compress the 15mm coil spring then install 2 massive “Rapide” mountaineering shackles (105mm long X 12mm thick) between successive turns of the spring, one on each side, to hold it more closed. After lowering again, I got the drop I needed at the top to install the shims, using 45 degree needle nose pliers. After jacking up the strut tight on the carefully positioned shims, securing the studs with new 10x1.25 grade 8.8 nuts and washers, at 35ft.lbs torque (no higher as the studs are only press fitted), I inserted 16ga stainless wire through all the shim eyes and twisted it off. This eliminated any possibility of the secondary (those not having a bolt through them) shims falling out.
At the front, after disconnecting the sway bar, I found that the strut lowered enough to allow insertion of all the shims, and I next secured the studs with new 10x1.25 grade 8.8 nuts and washers, at 40ft.lbs torque (maximum for these nuts). I cleaned off the top inside face of the secondary shims and adjacent turret with alcohol, then epoxied the inside tops of the secondary shims to the turret edge for added security against shifting.
The 4 wheel alignment check showed that only the front toe-in was out of spec, and was easily adjusted. For tires, the maximum increased size which fits in the wheel well and struts without rubbing is P225/75-R16. This tire is about 0.45” greater radius than the standard size, hence 0.45” radius lift is provided. After research, I chose Hankook Dynapro ATM tires, and I found that the stiffer sidewall of this all terrain P tire provided approx. 0.30” further lift.

Conclusion: Tires look exactly right in the fenders and in proportion to the whole slightly raised vehicle, ride well and are quiet. Reviewers say they perform very well off-road, which I will soon find out for myself. The Highlander still handles in a manner essentially indistinguishable from before the 1.25” lift, which is to say, well. The increased tire radius will only slow the speedometer & odometer by 3% - but they are usually built 3% fast anyway! There will also be a 3% theoretical drop in maximum thrust at the wheels, which will slightly reduce acceleration and hill climbing ability – very minor in my opinion. I am well satisfied with the final result, for which in my opinion the advantages far outweigh the disadvantages.

P.S. I also developed a design which would have provided a total of 2” lift, solving the problem of the short strut top studs. However, an off road shop advised that they thought that the extra 1.25” drop of the hubs and resultant extra angular movement on the drive shafts, would be too much strain on the CV joints. I took their advice.
 

Attachments

·
Registered
Joined
·
19 Posts
Looks like you put a lot of thought and engineering time into this. My hat's off to you, a lot of guys just slap on parts without really thinking about what they're doing, or pay someone else because they don't care to learn.
 

·
Registered
Joined
·
29 Posts
Discussion Starter #3
Thanks CompBCurrie. Yes, I did put a lot of thought into it, particularly on the shape of shims which could fit through the strut holes, be stable in place, and yet together provide a large contact area between the top mount of the suspension and the underside of the turret. I had an aversion to dropping the entire strut out of the vehicle. It seemed to me that although this would have made it easy to fit fewer spacers over the studs, even a single spacer, it would be much more difficult and expensive to shape 1/2" stainless steel in larger pieces with curved or multi-faceted sides, particularly on the inside face. I designed shapes to the cutting limitations of the bandsaw and the drill press. In fact for the bandsaw I made a secondary clamp out of two 4"x10"x1/2" steel plates arranged as a pair horizontally with two 1/2" studs between them, with one end of each stud into a threaded hole in the bottom plate, in order to be able to clamp firmly these small awkward shaped shims, at all angles, inside the regular vertical jaws of the bandsaw clamp whilst being cut. It made it much easier to cut the chamfered corners etc. as the shims could be held in a horizontal plane at any angle whilst being cut. Nearly all my time was spent on design and fabrication of the shims, the actual installation went relatively quickly. The Sandvik Cobra saw blades, 1/2" deep and 10-14tpi, running at about 150sfpm under medium pressure, were simply amazing. At the beginning, I used another supposedly high quality blade, and it was dead blunt by the second cut. With the Cobra blade, by the end of the job I had cut a whole cup full of stainless steel filings, but the blade still felt razor sharp.
 

·
Registered
Joined
·
1 Posts
I echo CompBCurrie's comments -- well done, and thanks for documenting your efforts so that it can be shared with others. Can you post some pics to your gallery so we can see the final results?
 

·
Registered
Joined
·
29 Posts
Discussion Starter #5
I will see what I can do about posting some pictures. The modified vehicle continues to perform very well, and I like the Hankook tires a lot.
 

·
Registered
Joined
·
2 Posts
i have been looking for a kit for a while and now that ive come across this i cant wait to make it! thank you for doing all the hard work!
just wondering if you could send me a couple of pics of the outcome?
thanks
jacob
 

·
Registered
Joined
·
29 Posts
Discussion Starter #9
In my main post you can see a photo of edges of top shims to front strut. The rear strut top shims are tucked in under a rather small access hole, not conducive to a photo, probably only the s/s retaining wire and the eyes would show well, but my pdf sketches show the design. I have a side elevation of the raised vehicle in my photo gallery. I haven't posted a photo of the strut elevation with the wheel off as the modifications are out of sight at the top, and the rest of the strut elevation is unaltered except everything is lowered by 1/2". I would be glad to help further if you could let me know what kind of photo would help you.
 

·
Registered
Joined
·
2 Posts
sorry it took so long ive been having major computer issues but for some reason i cant view the pics you took, i was just wanting to see a view from the side showing the whole vehicle just to see what it looks like afterward if you could pm them to me that would be greatly appreciated
Thanks
Jacob
 
1 - 10 of 10 Posts
Top