After years of nursing my air suspension, it's time to do the rear coil spring conversion. Thanks to the resources on C.L., I have studied up on this proposition progressively, knowing the day will come. Due to a "sudden need," my ultimate plans (lift, tires and some other mods) are cast aside in order to attain immediate functionality. Therefore, trying to source some used OEM springs locally. For now, stock height and a decent ride are the goal.

Just want to make sure I am 100% solid on knowing what I need. This is a KDSS truck, so I need to be sure that what I have seen other owners do would work on my rig (never seen a KDSS version converted to coils). Please consider/comment on the following:

1) Springs from a non-TRD Gen. 4 Toyota 4Runner or a non-TRD FJ cruiser (uncertain of any years that should be targeted).

2) It's been noted that a Monroe kit and maybe others are simply springs, no insulators or retention at the axle perch. This seems sketchy, but does it work, especially with OEM springs? I gather shock travel would limit springs from "popping out" and that the spring ends will generally remain in place due to axle tension and weight. I'm still uncertain about ride height with and without perch/insulator kits, though I do note that Metal Tech indicates stock springs with their kit = stock ride height.

3) Am a a cheap-a$$ for seeking OEM take-out springs, when something like a Monroe kit is pretty inexpensive(<$200)? IDK how ride would compare between inexpensive aftermarket and reasonably used OEM.

4) additional concerns for KDSS?

All thoughts and ideas appreciated. Thanks!

 

If you drive around with the cargo area empty, 3rd row seats removed, 4th gen 4Runner rear springs should get you close to stock height, assuming your rear coil conversion does not add any lift height (Metal Tech's conversion kit does not add any height, SSO, Dobinsons, and others DO add some additional height). If you leave the 3rd row in and have some other static weight in the back, go with FJC springs. You can save some money using an aftermarket upper spring isolator, but I would want one so you don't get metal on metal noises from the rear springs.

Personally, I'd prefer used OEM springs over new Monroe springs. Especially if you're thinking you'll lift at some point in the future, save some $$ and go with used springs now.

KDSS doesn't change the rear coil conversion process, but you may end up with some "KDSS lean", Treaty Oak Offroad has made some spacers to correct for this, but not sure it's something they stock, or just do a run from time to time as demand dictates.

 

I don’t have an issue with used springs but just make sure they don’t have like 100k miles of wear on them already.

 

Thanks folks,

The local search for FJ or 4Runner springs came up empty; none in the parts yards or local classified including Offer Up and Craigslist, and none of the suspension specialty shops wanted to play, claiming liability concerns over removed OEM items (defective spring steel, really?) and/or were more focused on upselling to a full suspension, installed. Like I said, this is a temporary measure, so random Amazon suspension wins! My Suncore rear suspension air bag to coil spring conversion & gas shock kit for $115.04 should arrive next week. Even though they still work and show no signs of leakage, I decided to replace the original adjustable shocks.

I will report back on how how this el-cheapo solution works out.

 

Sorry I’m just trying to understand why go through the labor twice? Buy once, do once.

 

Simply because I want the final state to be "done right." While I have contemplated an overall vehicle transformation for some time, I have not selected all the parts and pieces, let alone allowed procurement time. I have not even found the tires I'd like utilize. Everything else is reverse-engineered off the tire selection. It will be a slow moving, methodical upgrade to achieve the lift and functionality I desire.

I'm okay with a re-do involving inexpensive parts, but I've seen too many folks jump into an elaborate suspension system that' ends up being modified or re-done when it's determined that shortcomings exist. The labor is pretty minor really. I also hope to demonstrate that a simple airbag delete can be serviceable on a budget. More than anything else, I need the rig back on the road soon.

 

Ahh…I see your thinking since there’s an urgent need. Not sure if supply chain is still an issue but last Fall when I started down my upgrade rabbit hole, it took nearly 3 months to source my suspension and misc parts from Dobinsons out of Australia.

 

I converted mine to rear coils for under $350CAN using used FJC springs, OEM upper insulators, and the Metal Tech conversion kit. I had originally used the SSO conversion kit, not realizing it added additional lift, and ended up being too tall in the rear, so switched to the MT kit.

Everything but the springs was re-used when I installed the lift at a later date, similar to how you're looking to proceed.

 

I used oem LX470 rear spring with isolator installed with oem airbags inside coil springs and hacked the high control switch to maintain the ride high H/N/L as i wanted to be, it´s run perfectly fine.

 

Too complicated .
I am replacing my air bags with more air bags when it happens as I love the air ride .
Mine has 100K miles on the replacements , replaced at 83K miles

 

Time to share my experience with the coil spring conversion; finally got around to doing it this weekend. It took me five hours in my driveway, including a run for a new 1/2" air impact, because my tire retailer over-torqued the lug nuts and I had the feeling that I would break studs if I went with a long breaker bar. If it took me five hours, somebody with a well-organized shop and a lift could accomplish the job in two hours or less. I didn't take pics, but trust me, it looks like you think it does.

In review, I had one leaking air spring and the compressor gave out due to excessive duty, pumping air into the atmosphere. I purchased this from eBay: Rear Air Suspension Conversion to Coil Spring & Gas Shocks for 03-09 Lexus GX470 for $165 including delivery (Suncore brand). Clearly this is a Chinese product - the instructions are a joke, with plenty "lost in translation." It's too soon to give a definitive quality observation, but all indications are that it' is very decent. First drives provided an excellent ride quality. With 185,000 miles on the original electric adjustable shocks, I'm quite sure my ride was compromised by their worn-out state. So far my experience is unladen, and the rear height is similar to stock air springs set to high. The height implies there's room for a load to compress the suspension. It's very smooth over bumps - I went off road for some minor testing and was very pleased with how it handled a dry desert washboard challenge. I got enough articulation at one point to trigger release of the rear sway bar (KDSS) and it performed just fine. I would not know the difference between factory and this mod if I were placed in a blindfolded comparison test.

Observations;

1) The job is easy. If you have ever wrenched on projects more complex than a spark plug or oil change, you can do this. It's caveman-simple!

2) I used jack stands on the frame and two floor jacks to manipulate the axle. One was always supporting and/or serving as a fulcrum at the differential. The second jack was deployed to tilt the axle in order to achieve sufficient space for spring placement. I think KDSS limited my ability to influence the axle geometry more than would be the case on a conventional rear suspension. If any lift had been included, I would have had to drop the sway bar, panhard and KDSS hardware; I achieved just the right amount of room to insert the springs via jack manipulation.

3) My override bump stops were destroyed by perhaps 10 miles of driving on dead air springs - they were brittle.

4). My driver side air spring top retention clip was missing. I cannot say if this was a recent occurrence or if the shop that swapped bags for me about five years ago messed up or simply failed to install it (I can see that placing the clip would be possibly the most challenging step of an air spring).

5) I have yet to remove the ride control console assembly, but I did buy the "cubby hole" to plug the space. No dash lights displayed so far, but I will pull the appropriate fuses and relay in order to avoid future annoyance or a run-on compressor if mine decides to come alive again, or maybe I will remove the compressor, but not until I'm performing suspension mods later on.

6) My shock swap was almost super easy. I did it after the springs were in place. The only trick is that the fender well liner leaves virtually no room to access the top nut. I was tempted to attack it with a sawzall, but I struggled through the hassle of working in a tight space,

In summary, I'm glad I picked this path. Never again to suffer the frustration of air leaks or failed bags! As I demonstrated myself, an air spring swap is tougher than the coil spring conversion. In retrospect I could have accomplished either, but the air lines and the air spring top clip might push that job toward a shop, as it once did in my case.

I wholeheartedly recommend the coil spring swap, noting that you can start around $100 for spring-only kits, on up to four figures if you are staying at stock height. I would consider sourcing OEM parts from a wrecked 4Runner or FJ Cruiser, but a few clicks on eBay was the best use of my time.

 

Hello to all! First post here as I’m new and having this plan as well to convert air springs to coil springs on my 2004 GX470. I’m looking though for “buy once, do once” conversion kit. I want a kit that would maintain the normal height of the car but, a one inch elevation should be okey,
I would appreciate any suggestions/recommendations. Thanks

 

Thanks for OP's information!
I am about doing the the coil conversion on my 04. I am very much want to keep the stock height. I read the information about the less expensive eBay part, FJ/4Runner coils, Metal Tech kit.....
OP, I have some questions.
1. Does your conversion keep the stock height?
2. Had you considered the Toyota Spring seat 48302-35040? Or the kit has its isolator?
3. Is there any other mounting hardware needed?
Thanks