Have Previa - Will Lift

or
How to Lift a Previa and Fit Taller Tires
Using All Off-The Shelf Parts

“Great car; needs more clearance” is the muttered refrain from legions of Previa owners.

I’m on my second Previa – a ’96 SC AT. Several years ago, around the turn of the century, I used to drive past a house that had maybe 20 Toyota breadbox vans and Previas strategically parked around the place. Obvious nutcase. One day I noticed that that one of the Previas had a somewhat more erect stance than the one parked next to it. Next thing I know I’m knocking on the door and out comes a handsome fellow who is pleased that I noticed the difference (in the Previa, that is) and goes on to explain how he did it, and gives me the web address to the forum where he had documented the process. Whoa! Great job! (Does anybody have that link?)

In a subsequent visit he mentioned that the front CV joints would complain at full lock, so I suggested lowering the front diff a little. I figured it would be pretty easy, as I had recently removed one at U-Pull-It. Couple weeks later his thread is updated to include the details on lowering the front diff. After that he also detailed the fabrication of the adjustable upper link rods for the rear axle. Nutcase maybe, but a man of action fer sure.

Some time during these 3 or 4 front porch conversations we commiserated on the front tire size problem: raising the suspension is one thing; fitting larger tires is quite another because the top of the tire is pretty much up against the spring seats. He gave me a pair of struts from his scrap pile so I could experiment with lowering the mounting tabs to gain tire clearance under the spring seat. I worked up some drawings and took the dummy struts to a race car fab shop, but after long delays and numerous phone calls the place burned down! Back to square 1.

Then one day I drive past the Previa guy’s place and it’s all gone! All of it. And his postings on the forum abruptly stop too. WTF?

A few years go by while I ponder the Previa lift challenge. I study Zenseeker’s website; I locate a Previa guru in Eugene, Oregon, who supplies me with parts and technical advice. A plan is hatched and I start collecting parts.

Fast forward 4 or 5 years. A few months ago my pal in Colorado, who introduced me to Previas while they were still making them, sends me a link to a different forum with a thread on lifting a Previa by fabricating a coil-over conversion for stock struts and a simple lift block. That’s when I discover the forum (this forum) is moderated by none other than my former Previa guy, Tim. Most of you saw that coming. He can jump in here and dispute (er, correct) any details.

OK, it’s time for action. I have the parts, the tools, and the time. I even have a lift! So here’s the story on how I lifted my ’96 SC AT a total of 4 inches by using stock Toyota struts and taller tires.

First, an acknowledgement to Tim for daring to be the first. His excellent documentation inspired a lot of others. Second, a nod to mountainhick for finding a way to fit larger tires. I wanted to take it one step farther by using off-the-shelf struts, thereby making future replacements cheap and easy.

Mountainhick posted a laundry list of struts he measured and rejected, ultimately modifying the stock units with coil-over inserts. I took the suggestion from Zenseeker and checked out the early Sienna struts. What I found: the mounting hole diameter and spacing, the shaft diameter and thread, and the spring seat are identical to the Previa struts, and they have about 2 inches extra length below the spring seat, just where it needs to be to fit larger tires. Perfect fit? Not quite: the bottom "saddle" that surrounds and bolts to the steering knuckle is narrower than the Previa strut. You could cut it off and weld on a new saddle, but you could do that with any strut - if you could find somebody willing to weld a gas-charged strut. Besides, I want to use a stock, unmodified, off-the-shelf strut. I had a couple of bare steering knuckles (thanks to Gary Fisher, the Previa guru of Eugene, OR) and they had a lot of meat on the strut mount boss, so off to the machine shop they went. Two hundred dollars later I had a pair of Previa steering knuckles that accept stock Sienna struts. Yee haw!! The rest is really just bolting it all together.

A few details:

I assembled the Sienna struts with all new Previa parts: springs, spring rubber cushions, upper spring caps, and strut mounts. Apparently Toyota equipped Previas with several different front springs, depending on the car’s weight – the dual sunroof models with center captain’s chairs being heaviest had the stiffest springs. Nowadays they list only one part number for the spring so I bit the bullet and ordered a pair. They turned out to have the same nominal 15mm wire diameter as my originals but are about an inch longer. That length difference could be attributed to 20 year old sacked out springs. Next time I’ll get Sienna springs to match the struts because I assume the front engine Sienna has stiffer springs than a mid-engine Previa. That said, the new springs are excellent.

Since I was starting with bare steering knuckles, they got new bearings and hubs. I also pressed in longer wheel studs in case I wanted to add spacers behind the wheels. Turns out I didn't use any spacers but those long studs look cool!. And new dust shields because removing them from the old knuckles requires pressing out the hubs, which destroys the $100 bearing. The ball joints and brakes were fine so they went back on.

The welded-on brackets for the brake lines and ABS wires are all wrong, so I cut them off. I had longer 1-piece braided brake lines made. My car doesn't have ABS.

The sway bar links line up with the Sienna struts perfectly.


I slotted the holes in the struts to accept eccentric camber adjuster bolts, but that was overkill. Since doing the lift I have learned that Toyota can supply special bolts with necked-down shanks for more adjustment, or I understand replacing one bolt in each strut with a 1/2-inch grade 8 bolt will also work. Either way, no need to modify the struts.

I fabricated and installed 1/2-inch spacers above the strut mounts to allow strut replacement without ripping the interior of the car apart. They attach with bolts from above that pass through the regular strut mounting holes in the body, then thread through holes in the spacer far enough to pass through the strut mount (knock out the studs first) and fit nylock nuts from below. Pretty tedious getting those nuts installed but it beats tearing the dash apart, IMHO. In the future I can remove/install the struts entirely from below. I did all this to make strut changes easier, and obviously it gained a little more lift, but it’s not at all necessary. These spacers can be any thickness you like, but a total of 3 inches lift (2” with the longer strut and 1” spacer) is pretty much the limit without getting into CV joint issues and tie rod angularity problems that create a lot of toe change, and maybe bump steer, as the suspension works.

I followed Tim’s lead and lowered the front differential assembly one inch (1/2-inch at the rear mount), thus eliminating any CV joint angularity issues. Rather than spacers, though, I modified the diff mounts by machining out the annular web inside each hanger and welding extensions on top of each. A pretty simple mill, lathe, and weld job. Mountainhick doesn’t mention lowering the diff; I'd like to hear if he has any CV joint clatter at full lock and/or full strut extension, as Tim said he did before lowering the diff. In case you’re wondering, the change in the front drive shaft u-joint angle is imperceptible.

In the rear, Tim nailed it with the Mustang rear springs. They install easily and perfectly (disconnect the shocks parking brake cables to allow the axle to swing low enough), yielding about 3 inches of lift. Again, following Tim’s lead but in a different manner, I modified the upper control arms so I could adjust the rear pinion angle and gain some shock clearance, but I ended up with them adjusted back to near-stock length. Probably another bit of overkill. That rear drive shaft is so short that the angles of the two u-joints need be as close to identical as you can get them. That is, the pinion shaft must be parallel to the Transfer case output shaft - especially with the longer springs. Otherwise you get a horrible rumbling back there. Ask me how I know.

Tim fabricated extensions for his rear shocks; Did mountainhick? I don't like the bottom mounting stud; it's too vulnerable. I doubt I'm the only one to break one off. The solution is dead simple: a shock mount stud in the existing hole in the rear axle bracket above the lower shock mount and a pair of conventional double-eye shocks. I need to space the bump stops down, as Tim did. There’s a lot of travel back there (good), but the rear suspension jounce is limited by the shocks bottoming out (not good). I also had a longer rear brake hose made, but haven’t installed it yet. I lucked out and got the brake proportioning valve adjusted right on the first try; pretty much at the end of the available adjustment though.

So there it sits on my drive-on lift – 2 ½ inches higher in the front and 3 inches higher in the rear, more or less, with about 2 more inches of clearance under the spring seats for taller tires. Looks good!

Off to Les Schwab, the pre-eminent tire store in the Northwest.
I’ve bought a lot of tires from them over the decades. I wanted the biggest LT (6 ply) tires that would fit, and they were willing, even eager, to try a bunch of tires ‘til we found the right one. First on was an LT 235/75R15 (29” tall), but it tore up the plastic fender liner lip behind the LF tire when I turned the steering just sitting there at static ride height. It was sure to interfere badly with the upper fender lip under steer/bump conditions. Bummer; that’s the tire I was really hoping for. There are no LT 225 15 inch tires, so next we tried a LT215/75R15 (about 28” tall); it fit nearly perfectly. These are about the largest tires that will fit without trimming plastic and/or tin in the front wheel wells - the left one rubs very slightly at full right lock. To my eye, they look great. P225-70R15 would probably also work if you don't need 6-ply tires. Lastly, LT225-75R16 might work, but they are 10 ply and require new wheels. The important point here is all these tires fit below the spring seat – that is, with the Sienna struts the tire size is limited by wheel well clearance, not by the spring seat. Plenty of room in the rear wheel wells, BTW.

A word of caution if you’re thinking “I don’t care about cutting up the fenders, as long as I can mount them 44” Monster Mudders”: my tire barely rubs at full right lock on the plastic panel in front of the LF tire. That panel protects the intercooler on SC (supercharged, aka blower) models, like mine. So if you cut it away you’ll expose the intercooler to water spray, salt, mud, rocks, road kill, etc. from the LF tire. Maybe the non-SC (normally aspirated or NA, aka sucker) cars don’t even have that panel since there’s no intercooler, so you have a bit more Sawzall latitude. But that brings up another consideration: All blower Previas have 3:73 diff gears; you could fit 4:30 gears from a sucker car to make up for taller tires, as mountainhick plans to do. But if you’re starting with a sucker car you have nowhere to go for deeper gears, which you will surely need with any tire taller than 29”. One exception: if you have a manual transmission Previa you can swap in a 2-speed transfer case from an early Toyota breadbox van and have low range 4WD. Won’t help on the highway in hi range though. BTW, that transfer case won’t mate to the Previa automatic transmission; I tried. Besides all that, remember we’re dealing with a light van here, with pretty light duty underpinnings. Tall tires and low gears is a recipe for twisting off u-joints and axles.

My car has stock 3.73 gears. I was prepared to swap in 4.30 gears, depending on what tires I ended up with, but that turned out to be not necessary. As a bonus, the speedo is now dead accurate according to my GPS app.

After completing all the work the shakedown cruise was a 3200 mile trip to Baja and back. And I mean that literally. We mounted the tires on a Tuesday afternoon, but they didn't have time to do the alignment. So we packed the van the next morning, got the alignment, and left for Mexico. 4 days driving each way, and half of that in winter white-knuckle conditions. I am pleased to report the Previa performed beyond my highest expectations. It goes straight down the road, handles better than ever, has ample clearance in snow and on primitive Baja roads, and still gets the usual 20 mpg.

3 years of research, planning, preparation, and parts collecting; 12 days on the lift. It's no rock crawler, but now it's a light truck not a soccer mom van. So far I don't see the down side. I am more than pleased. As Gary Fisher said when he saw it: "This is what it should have been!"

That’s enough yakking for now. I’ll post pictures, links, part #s, etc. later.

Your comments and questions are welcome.

Hi tbuyan! Thanks for the detailed write-up & I'm looking forward to pics. I remember you as I think you were possibly the only person that has noticed my Previa was higher than stock (most folks don't notice such things). Yes, we cleared out from our place in Battle Ground. We downsized, sold that house & moved as that area was terrible in regards to tweakers/metal thieves. I got tired of being targeted by them and figured it was time to leave before I ended up killing somebody (I had developed enough malice to kill if I ever got my hands on one). Much happier here in our new location as nobody messes with my stuff. Also happier here at this website (TVT) as Gwen (llamavan) & I have complete control and are able to prevent site from crashing due to silly things (other site owners/admin often neglected to pay bills and things kept getting turned off).

Sadly, due to life and vehicle needs, my lifted Previa has just sat in the same spot for the last 3 - 4 years. A few times I went to move it and the battery was dead. Each time I charged it and took it for a short drive, but alas, it sits again (for months) and same thing happens. I guess I should probably pass the torch to somebody else and sell it.........anybody want it? I got tons of extra parts. I'm starting to wrap my mind around letting it go. $3k and it's all yours :yes:.

FYI, I'm pretty sure you can make the 2 speed transfer case fit an automatic Previa, but 1st you'll need to find an 87 - 89 van single speed transfer case (for parts), split the cases, and swap the input shafts. Once you have a 2 speed transfer case with a single speed (automatic) input shaft, the splines should match. I haven't done this yet, but according to my research it looks like this should bolt-up and work. All other dimensions, bolt patterns, and even original drive shafts should match-up. Buy my Previa and I'll throw in all the parts you need to make that happen :thmbup:. Tim

Thanks +1 for the write up.

Cool that you had the resources to machine the steering knuckle. That's what stopped me trying to find other taller struts to fit.

Yes, I lowered the front diff.

Yes, I added extensions on rear shocks, but at the top. It's still on the to do list to attach lower mounts to the axle bracket like you did. I have had the double ring mount shocks ready to install for the last 2 years. Can you post pics of your lower shock mount? just curious if it's similar to what I have in mind.

Here's how it started - November 2010. 205/60-R16 tires on Nissan wheels, I think.
Love those running boards.

Right here I've been trying to post a photo of the van with P205/75-R15 Blizzaks just before the surgery, but the site refuses to upload the file. So instead here's a photo of the new Sienna strut and the take-out Previa strut. As you can see, a gain of 2 inches. BTW you need to add an inch and a half to those numbers to get the actual measurements because of the drywall t-square cross bar that you can't see in this photo.

Strutectomy in progress. Or is it a strut transplant? The new rear springs are already in. Now you can see the entire t-square and why you have to do some mental arithmetic to read the numbers.

I'm trying to load these pictures in a logical sequence, but the site refuses to upload some of them. So the sequence is all screwed up. Sorry to jump around so much. The half-inch threaded steel spacer secured in place with bolts down through from the top. No need to tear the dashboard and airbag apart next time I replace a strut.

In order to thread nuts onto those bolts sticking down through the spacer, I needed to drill out a couple of the holes in the upper spring cup so that I could get a 3/8 drive 14mm socket up through. Still was a bit of a wrestling match, rotating the strut on the mount to line up with the 3 nuts. Next time I'll drill out 4 of them for better access.

Adjustable upper control rod in place. 5/8" billet ends and chromoly tubing from Jeg's or Summit. I don't think this step is necessary. Yes, I put a nut on the bolt after taking the photo.

The rear shock bottom mount stud. The hole is already there! Sorry, but the photo of the studs on the bench showing the other end won't upload. Neither will the photo with shock installed. But a screen shot of the error message will. Ha!

I guess I never took any before/after photos of the machine work on the knuckles, but this one pretty clearly shows how much metal is removed. About 5mm on each side of the knuckle. That spot-welded pad at the bottom of the strut tube, just above the mounting bracket is what's left of the brake line/ABS wire support tab after a little hacksaw work. Zip tie now secures the new brake hose to the strut. No ABS on this van.

Another view of the same strut. Note the sway bar link bolts up perfectly. Also note the eccentric camber adjuster. Don't bother.

2 1/2 inches clearance above the P215/70-R15 Blizzak.

I love this one. Lifted Previa on brand new rubber. 2 days before Christmas in the sunny Pacific Northwest.

First day out.

Awesome pics! Thanks for sharing :thmbup:. Those guys at the Battle Ground Les Schwab are awesome! There's another Les Schwab right next to where we live now, but I still drive the extra 18 miles for service at the BG store........well worth the extra drive. Tim

About a month later I snuggled up to this anonymous Previa for the before/after shot. Still sunny. Should have parked a lot closer though; the mirrors tell the story!

Thanks for the write up. I am going to attempt this later this year. When I do, I will try to post pictures too.

Quote:

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Originally Posted by tbuyan

The rear shock bottom mount stud. The hole is already there! Sorry, but the photo of the studs on the bench showing the other end won't upload. Neither will the photo with shock installed. But a screen shot of the error message will. Ha!

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http://www.toyotavantech.com/forum/a...1&d=1454655230





Can you tell me/us a source and or part number for this stud?

my plan was different, this is simpler/more elegant.

Thanks

Sorry for the delay. Who would have thought that the rear shocks and mounts are the most challenging part of the entire project? But they are.
The shock mount studs were something I already had in my junk collection - er inventory. I probably found them at a swap meet or yard sale.
I just Googled "shock mount stud" and found dozens of results including this:
http://www.ebay.com/itm/UNIVERSAL-SH...-/221463424618

However, as elegant as this solution seems to be, I have since changed it because my shocks were bottoming out too easily. It looked like the studs had bent, but in fact the mounting plates on the axle were deforming. I had to compress the shocks several inches to slip them onto the studs and there was not enough travel left. Shorter shocks would help but that would reduce overall travel, negating one of the advantages of the longer springs.

I tried drilling new mounting holes in the plate, which moved the studs down about an inch and a half, but that was not enough. So I mounted new shock brackets on the trailing arm using the original shock mounting holes. I inserted bolts up from the bottom so they do not protrude downward, as the original Previa shocks did. That cured the bottoming out problem, but now they top out too soon. That is, I have very little axle droop before the shocks reach full extension. Better than bottoming out, but it can't be good for the shocks. I could attach limiting straps like the rock crawlers and desert racers do, but I'd rather just get the shocks right.

By the way, I got those lower brackets at a 4WD shop, but here's a source:
http://www.qa1.net/suspension/street...onversion-kits

So I'm still working on it and will keep you posted. I'll post a picture of the current setup next.