The Spoon Sports strut bars come with M10 bolts and are threaded for M10 bolts. The thing is that the brackets that attach to the chassis have M12 sized holes in them! Why is this stupid? Well… Once you put on the strut bar and don’t torque it down, there’s 4mm of play from side to side. The chassis has to flex extraordinarily before you’ll feel the strut bar kick in to prevent further flexing.
The solution is not to torque down the bolts as hard as you can. Believe me, I tried. I stripped one of the holes. The damn thing still moved though because I saw little markings on the brackets where te aluminum slid back and forth.
The correct way to deal with this problem is to buy an M12 bolt and re-thread the hole for an M12 bolt. However, I live in the good ‘ole US of A. Therefore metric bolts aren’t easy to come by. A wonderful thing is that a half inch diameter bolt fits perfectly with less than a 20th of a mm of play on either side! Now that’s tight!
Allright, on to the DIY…
This procedure takes a total time of two hours to complete for the meticulous DIYer. The fast working DIYer that can tolerate a scratch or two and a possible screw-up should be able to finish in an hour.
To complete this procuedure one has to have a certain degree of proficiency with hand tools. No other skills are required, although an understanding of how maliable aluminum is is useful in not messing up.
- electric drill
- 1/2″ drill bit
- 27/64″ drill bit (about $7.00)
- 1/2″ – 13 (threads per inch) tap (about $3.50)
- monkey wrench
- four 1/2″ stainless lock washers
- four 2″ long (I think?) 1/2″ – 13 grade 8 bolts
1. First take the strut bars off of the car. Take the base brackets off as well.
- The base brackets should come off because the strut bars will need to be put on by piecing them together before putting the whole thing on the car. Then torquing to press the base brackets into place. The rear strut bar seems to be an especially tight fit after this modification.
2. Drill out the one unthreaded hole on each side of each strut bar to 1/2″.
- If you’re not comfortable enough with a drill to control your drilling so that you don’t drill into the threaded hole, then do not proceed! Find a thin piece of steel to put behind the small hole so that the drill will contact the scrap piece of metal before it reaches the threaded hole.
3. Drill out the threaded holes on each side of each strut bar to 27/64″.
- You should start by putting the drill bit through the 1/2″ hole that you just drilled and center it based on that hole. That way the bolt will fit through that hole and thread straight in. If you don’t align the two holes the bolt might not find the thread and you won’t be able to screw it in.
4. Tap the 27/64″ hole with the 1/2″ – 13 tap using the monkey wrench to hold the tap.
- I used a monkey wrench because I didn’t feel like spending more money to buy something to hold the tap. The holder I had wasn’t large enough to hold that size tap. Remember to thread the hole so that you can screw in the bolt straight in through the 1/2″ opening. You’ll have to look at it as you thread it to align the two holes.
5. Now put the three pieces of each strut bar together and mount each strut bar to the strut towers.
- Fit the strut bar base brackets on top of the strut tower bolts and tighten them down all the way with the stock nuts. If you have a torque wrench, then torque them to 33 foot pounds.
6. Tighten down the new hardware to 33 foot pounds, or until the lock washer is seated.
- You don’t have to tighten the hardware down too much. I tightened it down to 33 foot pounds and I didn’t strip the threads. If you tighten it down until the lock washer is seated, then it should be enough as well. The bolt contacts the base brackets, so now the stiffness of the strut bar no longer depends upon the torque of those bolts.
Grey from civicforums