Page 1 of 2 12 LastLast
Results 1 to 20 of 27

Thread: Lifted All Trac Previa

  1. #1
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Lifted All Trac Previa

    I did some searching for a pre-fabbed lift kit, but could find nothing for the Previa. Since I have some experience as a tool maker and fabricator, I decided to build my own. Since the tire size is limited by the front struts, I decided that 2" would be about right for this project. Here are some pictures and details:

    I decided it would be easier to modify existing strut mounts than to build something from scratch, so I went to http://www.rockauto.com and found one their famous "close-out" sales on Previa strut mounts. I ordered 4 of these for only about $20 each. Here's what I got.




    The idea is to stack the strut mounts and weld them together. If this is going to work, then this bearing must be removed from the top mount (I'll need enough room to get a socket and extension down in there to install the strut mounting nut). This bearing is pressed in and also has a metal lip crimped in over the edge of it.


    Here is my answer to getting rid of that crimped metal that's holding the bearing in place.


    Here's what's left after 5 minutes with a die grinder.


    Now bearing can be driven out of mount.


    Okay, bearing's gone. That's it for the top mount.


    Lower mount doesn't need these 3 studs, so using a socket and a vise I press them out.




    Okay, that's it for the lower mount.


    Now it's time to do some shopping at the steel yard. I take the mounts with me and snoop around in the scrap pile. I find the perfect diameter and wall thickness, and have the metal guy cut me 2 pieces, each one 1 7/8" long.


    Burs are removed from the tubing and I use a wire wheel to remove paint from the places I want to weld on the strut mounts. Mounts are stacked together with metal tubing then clamped for welding. I use a hammer to gently tap parts into perfect alignment. Here we are ready to weld.




    Here's where the Tim's RV welding van comes in handy!


    To avoid overheating and damaging bearing, I decided to stitch weld and to cool after every 2 or 3 segments. This should be plenty strong.


    And here's the finished strut mounts after painting. These will lift the front exactly 2" higher than stock.






    Next I put the Previa on jack stands and remove the struts. Here is one ready to have the new mount installed.


    Spring compressor tools are a MUST. People have been seriously injured by removing mount nuts without 1st compressing and securing the spring.


    Once spring tension has been removed from the mount, the nut can be removed. Note: Strut should be laying on the ground aiming away from you and others (just in case the spring compressors slip). It's better to have parts flying sideways at ground level then to have things flying up toward your face .


    Here's the strut sporting it's new extended mount.


    Here's the top of the strut with the nut securing it to the new mount. That old bearing hole gave plenty of access for a socket and extension!


    Putting the extended strut and mount back on was a little more difficult. Things didn't want to line up due to the increased articulation of the A-arm. I was able to get the bottom bolt in by hand, then using a big C-clamp I forced things into position and installed the top bolt. Due to my concern of adversely affecting camber, after top bolt is pushed through, I tightened clamp more until bolts are pinched, then tightened nuts. This is not enough to compensate, but I'll take what I can get.


    Here's what you can see of my mounts after installed.




    Look at this unloaded lift!!!!




    Okay, so there's a problem. This extra lift has made my inner flexible brake lines too short. I have my buddy at Napa look these up, take note of the specs, then find a new line that's 2" longer. No dice on the 2" longer, but he finds ones that are 1 3/4" longer!!! This is so cool! I'll take 2 please!





    Note the wire tie holding my ABS sensor wire to the old screw mount. The nut plate and the screw part of the clamp are still attached to the wire harness, but I am not using these now. Length is okay with wire like this. Wheels can now be turned from stop to stop without interference on brake lines or ABS sensor wires.


    Okay, brakes are bled, front tires put back on, front is done!


    Time to do the back. I figured the best way to raise the back is to find longer springs, so I ordered a Moog catalog and started searching based on inside diameter, length, and gauge of spring. There is some guess work involved, and of course, a perfect match is illusive. A couple of springs come close to what I want. One is 3/4" shorter than what I want, but the gauge of the spring is about 10% bigger. The other is about 2" too long and also about 10% bigger gauge. I could get the longer ones and cut them down, or get the shorter ones and hope for the best. Well, I opt for the shorter ones and cross my fingers. The shorter ones are stock replacement coil springs for the front of a 65 Ford Mustang with a 6 cylinder engine. This is good news because this is a popular classic car and springs should be readily available. I go to http://www.rockauto.com and sure enough, I find my springs. I go with the Husky brand part # RC8088. These only cost $56 for the pair.

    So, with the Previa on jack stands (weight supported by rear axle) I remove the wheels and shocks and take a measurement.




    Next I disconnected the LSP & BV (Load Sensing Proportioning & By-pass Valve) linkage, support the rear of the van using the jack points and drop the rear end. There is enough articulation for me to remove the old springs by hand (no spring compressor needed). Here is an old spring next to a new one.




    Spring compressor is needed to install new springs.


    Springs are installed and jack is put back under the rear differential. I jack van up until weight is again supported by differential. Measurements are taken again. YES! the gamble paid off. New height is exactly 2" higher than before!!!




    Okay, so I go shopping for longer shocks. Bad news, nobody makes this type of shock that's 2" longer. Well fine, I'll modify some Monroe Gas Matics.

    Shock extenders would make the shocks too long, so I made my own extenders. The threads don't go far enough to do what I want, so I use a 3/8-16 die to cut some more threads. I purchased some 3/8-16 coupling nuts from the hardware store. I measured the nuts, then cut threads deep enough to position the bottom of the nut exactly 2" down from the shoulder on the shock.










    Now that the threads are cut, I measure and cut off the excess shock bolt. The objective is to have the threaded portion of the shock fill 1/2 of the coupling nut.






    Here is some 3/8-16 threaded rod I picked up from the hardware store. I cut off a piece and thread it into the other end of the coupling nut.


    I use double nuts to get a firm grip for tightening. This is nice because it won't damage the threads like a vice or vice grip would.


    I measure and cut to the same length of the old threaded area.




    Here's the extended shock next to the stock shock.




    And here's my new extended pair of Previa shocks.


    Okay, so the Previa has a LSP & BV (Load Sensing Proportioning & By-pass Valve). The LSP & BV's job is to increase braking power to the rear wheels when there are heavy loads in the van. As the weight increases, the suspension becomes more loaded and the rear end moves closer to the body. As this happens, the LSP & BV linkage pushes the arm of the valve up, and the LSP & BV allows more brake fluid to flow to the rear brakes. Due to the position of the valve linkage on the suspension arm, using math (and a little guess work), I determined that a 2" lift requires the LSP & BV linkage to be adjusted .78" higher to compensate.

    1st thing is to unclip the top of the spring retainer.


    Next thing is to loosen the jam nut at the bottom of the lower spring retainer. I was careful not to move the lower nut so I have a point of reference.


    After adjusting (extending) the linkage .78", top spring retainer is reclipped, and jam nut is threaded back up the rod and tightened against the adjustment nut.




    Okay, so there's one last thing. I was going to ignore this, but the thought of bottoming out and shoving a shock through the floor made me reconsider. Considering the increased stiffness of the rear springs, I doubt this would happen, but decided to drop the rubber snubbers just in case. This is a simple task, and all I did was cut some pieces of 2" steel tubing and drill some holes in it. I used these pieces as spacers for the snubbers. The hardware store had some metric bolts the right length, so installation was easy. Here's some pictures of this mod.











    So I finished it all and took it off of jack stands tonight. Here is the height from the concrete to the bottom of the passenger door area.



    Here is the height of the front bumper.


    New clearance of left front tire.


    New clearance of left rear tire.


    I drove it around the yard and it rides nice. 2" isn't very much, but it's very noticeable. I am still a little concerned about the camber issue as I don't see an adjustment for that on the van. I'll be taking it in for an alignment next, and I'll consult with the alignment guy. I may end up doing a few more mods to get that within specs and I will post this information here as it becomes available. Tim

  2. #2
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Lifted All Trac Previa

    Good news! Alignment is done and van is within specs! I took the van into Les Schwab for an alignment today & was lucky enough to get a seasoned tech. He tried several things to get the alignment to fall within specs (camber being the problem). Finally after all else failed, he put 1/2-13 grade 8 bolts into the upper position on the lower strut mount (original bolt was almost double that diameter). Then with both nuts loose, and full weight of van resting on tires (tires being on the sliding pads), he tightened these mount bolts back up. When checking the camber after that, he found the passenger side was dead on, and the driver's side was at .7 off. Out of curiosity I jumped in the driver's seat and had him check it again. With my weight on the driver's side, this brought both sides to .2 off (well within specs)! I needed to run some errands afterward and drove the van about 50 miles. I am very happy with the ride and it goes down the road nice and straight. After going through this, I can say with confidence that 2" lift is the maximum a Previa can be raised in this manner (without other complications). I am definitely glad I did this and I'm enjoying this van much more than before. Here are a couple of pics of the PS side lower strut mount with the smaller bolts in the upper position. Tim


  3. #3
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Lifted All Trac Previa

    I played around with loading and comparing the Previas today. I put 1,000 lbs (half ton) of pellets in each one and compared performance of each. All things are not exactly equal because the one I raised is a 91 All-Track, and the one I'm comparing to is a 93 2wd. They are both LE models however and both have the 15" rims and same size tires. The pictures below pretty much tell the story, but I wanted to add the 91 with the 65 mustang springs on the back carried the load much more comfortably and stable. The 91 still had some suspension left and the ride was nice. The 93 however was bottomed out on the rubber bumpers and every bump was harsh. Enjoy the pictures......(I hope you don't have dial-up.......sorry if you do). Tim































  4. #4
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Lifted All Trac Previa

    Well I've been concerned about the drive angles of my front axles and stress on my CV joints, so today I decided to take a look to see what I could do about that. I thought this would be a fairly big project so the plan for today was only to get underneath to survey and take a few measurements. I figured the best solution was to lower the front differential but I'd probably need to design and make some special parts. As it turned out the job was super simple and I was able to complete the whole job right away with just basic hardware available at my local hardware store!

    Here is one of the front differential mounts........there are 3 of these.


    Here's the hardware required to do the job: 3 bolts 10mm diameter X 1.25 pitch X 110mm long & a box of 3/8 X 2" fender washers.


    All I had to do was replace the factory mount bolts with the longer bolts and stack the washers on top of the mounts :P .


    I also got some longer bolts to remount the mount protectors (mini skid plates). The little bolt on top is an old bolt, the other 8 are new 8mm diameter X 1.25 pitch X 50mm long.


    I used some 1/2" nuts as spacers and reinstalled the little skid plate protectors.


    The limiting factor in lowering the differential was the proximity of the CV joint to the support brace. I was able to drop the whole differential down about 1 & 1/16". This left about 1/4" clearance between the CV joint and the brace.


    I only shimmed the rear mount about 7/8" This is so the u-joint would have a straighter shot at the differential. Here's a front view of the finished project.


    As I hoped, lowering the front differential drastically reduced the drive angle for the front axles. It made very little difference to the angle of the front drive shaft. The severe angle of the axles had me a little nervous before, but now I feel much better. Tim


  5. #5
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Lifted All Trac Previa

    Okay, so I have one more project to do to make this job complete. After getting the front drive-line and front axle geometry squared away I started thinking about my rear drive-line. A 2" lift probably isn't enough to warrant great concern, but I'm a stickler for details and I don't like the universal joints working any harder than they need to. I took a look under the van and decided that drive-line geometry could be improved by rotating the pinion upward. Since raising the van brought the rear axle slightly forward, I decided lengthening the upper control arms would be the best and easiest way to compensate and would raise the pinion at the same time. I'm all for killing 2 birds with one stone, so lengthening these arms is now the task.



    Here's an arm after removal. The math is a little bit tricky on just how much to add, plus I'm not 100% sure how far I can go before the shocks hit. I'd really hate to go through this more than once, so I decide adjustable is the best way to go.


    I found these adjustable links at a our local farm store. They are used to adjust 3 point hitches on tractors. These are actually pretty close to what I want and could almost be used as-is. The holes on the ends are the right diameter even, but the overall maxed-out length is too short. It's probably for the best as there would most likely be some noise transmission without the rubber insulators like the stock arms have. If I could have found them in the correct length, I might have just put them on and used some washers on each side of the eyes, but that is not to be. Okay, here's a link to these links (get it?....link to links?): http://www.doitbest.com/Tractor+Part...sku-759588.dib


    Some more pics:




    Before I move on I need to establish a way to hold things still and in the correct position. I make a crude jig out of some scrap aluminum and a piece of 2 X 4.




    Now for some cutting


    More cutting


    Parts secure and ready to weld!




    After welding


    Cleaned up and ready for paint


    Painted and assembled to stock length with anti-seize compound on the threads


    In playing around with these I found that 10 rotations of the body = 1" of travel. After installation I found 4 complete turns was the magic number, so that means .4" longer control arms puts my pinion & drive-line at the optimum angle. It's a good thing too because even one more turn would cause my shocks to hit! Here they are installed, adjusted, and locked into place.


    And here's the end result:




  6. #6
    Van Enthusiast gushaman's Avatar
    My Van(s):
    1987 LE 2wd capn chairs auto 1987 LE 4wd capn chairs 5speed Have owned:.......ive owned 8 other vans, i cant remember all of them sorry
    Join Date
    Dec 2010
    Location
    Nashville,tn
    Posts
    119
    Rep Power
    1

    Re: Lifted All Trac Previa

    WOW TIM! I am impressed, once again. Toyota couldnt (didnt) do it better themselves.

  7. #7
    Van Fan
    My Van(s):
    94 Previa AWD
    Join Date
    Jan 2013
    Location
    Coolorado
    Posts
    75
    Rep Power
    1

    Re: Lifted All Trac Previa

    What a great mod! I want to do this. I had a 91' 5 speed years ago, but stupidly let it go. Just picked up a 94 AWD day before yesterday. Do you know whether the suspension is the same and parts for modification the same for a 94?

    Thanks

  8. #8
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Re: Lifted All Trac Previa

    I have no experience with anything newer than 93, but I suspect all the suspension parts are the same. Good luck & have fun

  9. #9
    Van Fan
    My Van(s):
    94 Previa AWD
    Join Date
    Jan 2013
    Location
    Coolorado
    Posts
    75
    Rep Power
    1

    Re: Lifted All Trac Previa

    Quote Originally Posted by timsrv View Post
    I have no experience with anything newer than 93, but I suspect all the suspension parts are the same. Good luck & have fun

    Thanks Tim,

    I am looking at parts listed for the two and finding the same part numbers, so looks like a go. Any reason in particular you chose the Husky coils? They are not available at Rockauto, they are elsewhere, but but Moog 8088 are available at Rock. If I can order from one place, so much the better.

  10. #10
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Re: Lifted All Trac Previa

    I wasn't completely sure these would work when I ordered so I got the cheapest ones I could find ($56 for the pair). I got them at www.rockauto.com. They must have sold out. Moogs are probably better. If I were doing it again I'd probably get the Moogs too. Tim

  11. #11
    Forum Newbie
    My Van(s):
    92 Previa LE AWD
    Join Date
    Aug 2013
    Location
    BC
    Posts
    17
    Rep Power
    1

    Re: Lifted All Trac Previa

    Hello, I am new to this forum and have learned a lot in my short time here. Thank you Tim. I am researching SADS replacement options. Afterwards I could not stop myself from reading more and more into the wee hours of the night. I am very impressed with the 2" lift and the mods you fabbed to make your drive line straight and tight. Well done!!! Would you consider pre fabbing some lift kits for the prevs?

  12. #12
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Re: Lifted All Trac Previa

    Thanks for the kudos . I actually had thought about building kits and selling them, but unless I sold a lot, the price would be steep...........and then there's the liability issues. BTW, for any of you thinking about doing this, the purpose of this thread is only to show off my rig. I am not suggesting anybody else try it. Anybody using this information for anything other than entertainment does so at their own risk. How's that for a disclaimer? Tim

  13. #13
    Van Fan
    My Van(s):
    94 Previa AWD
    Join Date
    Jan 2013
    Location
    Coolorado
    Posts
    75
    Rep Power
    1

    Re: Lifted All Trac Previa

    Hey Tim,

    For rear control arms, what do you think about just cutting the shaft, jigging for 0.4" longer and welding some angle to splint the shaft rather than making them adjustable?

  14. #14
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Re: Lifted All Trac Previa

    Yeah, if I had known .4 was the magic number (and the maximum I could go), that's probably what I would have done. I only did it this way due to unkowns and variables. Tim

  15. #15
    Van Fan
    My Van(s):
    94 Previa AWD
    Join Date
    Jan 2013
    Location
    Coolorado
    Posts
    75
    Rep Power
    1

    Re: Lifted All Trac Previa

    Quote Originally Posted by timsrv View Post
    Yeah, if I had known .4 was the magic number (and the maximum I could go), that's probably what I would have done. I only did it this way due to unkowns and variables. Tim
    Cool. That'll be simpler to jig up and weld.

  16. #16
    Van Fan
    My Van(s):
    94 Previa AWD
    Join Date
    Jan 2013
    Location
    Coolorado
    Posts
    75
    Rep Power
    1

    Re: Lifted All Trac Previa

    My van is lifted! My buddy just happened to have one of these, which I borrowed:

    F492868.gif

    Made the strut work that much easier and gave me a head start compressing the rear springs before adding these:
    orly_7294.jpg

    To install the rear springs.

    Still have to take care of a bunch of the other details, especially front end camber looks BAD!!!

    But a good days work today!

    Front looks a good bit higher than yours Tim, which makes no sense to me. 2" lift in the strut mounts, just like you did them. Used the same srpings on new struts. I'll take a measurement tomorrow.

  17. #17
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Re: Lifted All Trac Previa

    I demand to see pics! The camber looked bad on mine too, but the 1/2" bolt in each of the lower strut mounts was enough to make it fall within specs. Here's the details on how that came about:

    Quote Originally Posted by timsrv View Post
    Good news! Alignment is done and van is within specs! I took the van into Les Schwab for an alignment today & was lucky enough to get a seasoned tech. He tried several things to get the alignment to fall within specs (camber being the problem). Finally after all else failed, he put 1/2-13 grade 8 bolts into the upper position on the lower strut mount (original bolt was almost double that diameter). Then with both nuts loose, and full weight of van resting on tires (tires being on the sliding pads), he tightened these mount bolts back up. When checking the camber after that, he found the passenger side was dead on, and the driver's side was at .7 off. Out of curiosity I jumped in the driver's seat and had him check it again. With my weight on the driver's side, this brought both sides to .2 off (well within specs)! I needed to run some errands afterward and drove the van about 50 miles. I am very happy with the ride and it goes down the road nice and straight. After going through this, I can say with confidence that 2" lift is the maximum a Previa can be raised in this manner (without other complications). I am definitely glad I did this and I'm enjoying this van much more than before. Here are a couple of pics of the PS side lower strut mount with the smaller bolts in the upper position. Tim


  18. #18
    Van Fan
    My Van(s):
    94 Previa AWD
    Join Date
    Jan 2013
    Location
    Coolorado
    Posts
    75
    Rep Power
    1

    Re: Lifted All Trac Previa

    I had a reply from chm1129 at the yahoo group that it will change when it rolls. That will be a while, I still have the tranny/transfer swap to do and some other stuff.

    I hesitate to do what you did with the 1/2 bolt. Very rough dirt roads here and I'd feel much better with the hole filled rather than any possibility of the alignment shifting due to some kind of road shock.

    Here are pics though:
    Attached Images Attached Images

  19. #19
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Re: Lifted All Trac Previa

    Wow, My camber never looked that bad.........but yes the height will drop a bit and the camber will also change some (for the better) when it rolls. About the bolt, I was a bit skeptical as well but considering the thickness/strength of the strut in that area, even just one strut bolt would carry more than the strut could handle.........so I'm good with it.

    I used my Previa for a back-up business rig for a year and put ~10k miles on it with a 1,500 lb load inside. We also drive on rough surfaces while towing a trailer and occasionally hit hard/bottom out. At some point I knocked the driver's front wheel out of whack & you could visibly see the camber was off (the opposite of your current problem). I took it in and they aligned it again. So far it's stayed good. I've put over 20k miles on mine since the lift. My struts were old at the time but I reused. Now they are starting to clunk, so I'll likely be replacing them soon. I don't think it's related to the lift, probably just time. Tim

  20. #20
    Administrator timsrv's Avatar
    My Van(s):
    Lots of them
    Join Date
    Jun 2010
    Location
    SW WA ST
    Posts
    3,205
    Blog Entries
    14
    Rep Power
    10

    Re: Lifted All Trac Previa

    You know, there's a guy over on the Yahoo Previa group doing this same mod. I think he goes by "previahawk" . Tim

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •