DIY: Cutting OEM struts (front) for Koni Yellow inserts
 

After reading the various suspension threads on these forums about springs/shocks vs coilovers, I decided I wanted to go for a modest drop (~1”) and do things right by replacing the OEM shocks with some aftermarket dampers designed to take the load of a lower ride height. My car is a DD so I wanted to retain as much of the stock handling characteristics as I can (while improving performance wouldn't hurt either). I didn't see myself adjusting the ride height very often and even if I went with coilovers down the road, I didn’t want to go cheap with them right now.

For the reasons above I decided to go with Eibach Pro-Kits and Koni Yellow Inserts. It wasn't actually until after I bought the dampers did I learn that I needed to cut into the OEM struts to make everything work (I know, rookie mistake). I was a bit apprehensive about doing the work myself, but with a little help from a friend I decided to take on the challenge and after doing much of the work over the last few days it really wasn't bad at all. I offer up this DIY for those of you who are looking to go with insert shocks (such as those provided by Koni) instead of other options on the market (like sticking with OEM shocks or going with coilovers).

First, directions I tried to follow can be found here: http://www.koni-na.com/pdf/boltstrut.pdf

Highly recommended (this will make your installation much easier):

1.) Get/buy/steal a set of OEM struts (front) from someone else so you don’t have to cut into your own and risk not being able to drive if you screw up. I purchased a pair from another forum member; they included springs & top hats for $90 shipped. Keep in mind that blown shocks are okay since you're just interested in the OEM housing where the inserts will go.
2.) A secure vice if you don’t have one already. I bought one from Harbor Freight for $27.
3.) #3 Pipe Cutter to cut the OEM shock (probably a one-time use tool for me). Also bought this at Harbor Freight (for $20).
4.) Dremel tool with cone-style sander.


Detailed instructions:

[1] Start with a pair of OEM struts (hopefully not the same as the ones on your car).
http://i685.photobucket.com/albums/v...ows/01_OEM.jpg

[2] Secure one OEM strut on a stable vice. Mark the center of the bottom of the OEM strut in preparation for drilling.
http://i685.photobucket.com/albums/v...llows/03_X.jpg

[3] Drill a small 1/8” hole at this location. Wear eye protection since a tiny bit of oil may squirt back at you initially since the chamber is lightly pressurized. The Koni instructions say to tape this hole then move onto cutting, but I just pumped all the oil out at this point since my taped hole was leaking oil and things were getting messy.
http://i685.photobucket.com/albums/v...s/04_drain.jpg

[4] Measure the length of the Koni Yellow insert from the end to the bump (1.75”) and subtract 0.25”. Measure this distance down from the OEM strut (1.5”) and mark around the circumference.
http://i685.photobucket.com/albums/v...s/05_mark2.jpg

[5] Secure a marked & drained OEM strut on the vice. Using the #3 pipe cutter, PATIENTLY cut the OEM pipe at the marked circumference. A ¼ to ½ turn per cut is reasonable. If you try to cut too much you will essentially make a thread on the OEM strut like a screw (you don’t want this).
http://i685.photobucket.com/albums/v...ws/06_cut1.jpg

[6] Once cut, pull out the OEM internals and drain any additional oil that may be in the OEM housing.
http://i685.photobucket.com/albums/v...separates2.jpg

[7] Enlarge the earlier 1/8” hole at the bottom of the housing to a size of ½” (Koni directions say drill a ~9/16” hole, but if you’re centered enough, a ½” hole is big enough for the supplied 12mm bolt to go through)
http://i685.photobucket.com/albums/v...ws/08_hole.jpg

[8] On the cut end, use the conic sander bit on the Dremel tool to sand down the cut edge enough (again use eye protection here since sparks will be flying) so that your Koni insert will fit most of the way down until it hits the bump on the insert. It should be a fairly tight fit. Instructions say you may need to use a mallet to tap it along some but I didn't need to do that. The sanding part took a little longer than expected for me since I think the pipe cutter indented the inside walls of the OEM housing a bit.
http://i685.photobucket.com/albums/v...ws/08_cone.jpg

[9] Using the supplied bolt and washers you should be able to pull the Koni Yellow insert all the way to the end at this point. I used some threadlocker (Loctite Red - about 1 drop per bolt) as recommended by the Koni directions.
http://i685.photobucket.com/albums/v...09_loctite.jpg

[10] Using a torque wrench, torque the bolt to 55 ft lbs per the Koni instructions.
http://i685.photobucket.com/albums/v.../10_torque.jpg

[11] Place the supplied rubber dust boot over the cut edge on your OEM housing to prevent rusting and make things look better.
http://i685.photobucket.com/albums/v.../12_finish.jpg

[12] You’re done and ready to put on your lowering springs & top hat etc. In the photo below you will see the Eibach Pro-Kit spring, the Eibach bump stop, OEM dust boot, white Koni bump-plate (seated right next to the Yellow insert), Koni spacer, OEM spring top/rubber bumper, OEM top hat, and Koni top nut. Make sure the Eibach spring is oriented correctly with Eibach printing right-side-up when installed. Place the Eibach bump stop with the wider opening down, then place the OEM dust boot over it. The Koni spacer can go on top before you put on the top hat pieces (or according to Koni you can put to the spacer in afterwards too).
http://i685.photobucket.com/albums/v...ws/photo13.jpg

[13] I did not have to use a spring compressor to put on the top nut. Instead, I just used my body weight to push the spring down while having my girlfriend hand-tighten the nut ... she's good at that :). Torquing it to spec was tricky partly because I was given two torque numbers, 37 ft lbs from Koni and 41 ft lbs from Toyota/Subaru. Since I didn't have the right adapters anyway to make use of my 1/2" driver torque wrench, I just tightened it slightly more than hand-tightening using a 9mm socket wrench and 18mm offset wrench.
http://i685.photobucket.com/albums/v.../photo12-1.jpg

[14] Now you're done with the final front strut assembly with aftermarket Eibach Pro-Kit springs and Koni Yellow inserts. Picture below shows the nut a little below the adjustment valve... hopefully it was torque'd somewhere between 37 and 41 ft lbs.
http://i685.photobucket.com/albums/v.../photo13-1.jpg

[15] They are now ready for quick remove & replacement with the ones currently on your car. :happy0180:
http://i685.photobucket.com/albums/v...ws/photo14.jpg

I will be using the following two DIYs for the install onto the car:
1.) http://www.ft86club.com/forums/showthread.php?t=10842 "Replacing Struts and Installing Coil Springs" by @DarrenDriven
2.) http://www.ft86club.com/forums/showthread.php?t=32414 "A simpler spring/strut install DIY -- no compressor needed" by @jeebus

Freakin awesome!!!! I was wondering about this! How is the ride?

Just doing the pre-work right now for the actual installation. Hopefully I will be getting everything (Pro-Kits & Koni Yellows) installed correctly on Saturday.

Nice! Can't wait to hear what you think! :happy0180:

Thank you!

Great DIY article.

Nicely done. Been wondering how the cut was to be made.

Thanks! Updated with some additional steps for a final front strut assembly (including springs, bump stops, top hat, etc.)

Your DIY was excellent, start to finish was 3 hours.
Koni Inserts, Swift BRZ Springs, HVT Camber Plates
http://i212.photobucket.com/albums/c...psb2d3e19b.jpg
1/2" drill bit was perfect!
http://i212.photobucket.com/albums/c...ps30b419f4.jpg
Dremel after the cut, with a stone cone deburrer was great advice.
1.5" measurement was perfect.
Initial Pilot hole drill was 3/32" for me, zero spray, lots of gas.

Re-installing tomorrow.

I used a 1/2" drill to enlarge the rear stock hats to accept the rear koni shocks.

Yeah, I used a 1/2" drill bit as well for the rear which worked perfectly. I actually just got everything installed last night (front & rear) and was initially disappointed with the amount of drop I got. It seemed to be somewhere between 0.5" and 0.8" all around right now, but I realized my ground isn't so flat on my after-measurements so that may invalidate my before-measurements anyway. :) At least after a few blocks around the corner and one night of settling, the drop on all four corners seem to be about the same (within 1/16"). Hopefully I get another few 16ths" after more settling in the week.

Initial driving impressions: On full firm, WAY too firm and not very comfortable for my DD. On full soft, it feels pretty much like stock. I may just keep it here or go 1/2 turn from full soft.

How do you like your Camber Plates and where did you pick them up from?

I may be looking into some Camber Plates plates in the future plus I might have placed my Koni spacer in on the wrong order... I have it below the spring top, but according to the Koni instructions, appears they should go between the spring top and the OEM top hat. Not sure if this would affect the end ride height at all.

www.turninconcepts.com

If you're talking about the collar that goes over the shaft, it fits between the OEM upper spring perch anyway if you take a look at it closely. You just want to make sure it ends up properly located between the OEM bearing center and Koni shaft.

So far they are acceptable. Still not mounted on car.
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