How To: Install coilovers on a Prius Prime

Note: Please use this as a guide. It is still up to you to use discretion and perform your own research and validations. I'm not responsible for any damages or injuries.

I added some pictures I took during the install.

FRONT

To replace the front suspension was much easier than the rear. Total estimated time is 2-3 hours from start to finish.

1. Start by masking where the existing wiper blade positions are, since you will need to remove them along with plastic trim piece under it.

2. Remove wipers. Pop the caps hiding the 14mm nut using a trim removal tool (non marring plastic removal tool). Use a 14mm socket to the nuts holding the wipers.



3. Remove the plastic trim piece. There are two end pieces that need to be removed first. Use the plastic trim tool and start on the upper edge close to the windshield. Gently lift the plastic trim off the windshield and them use your fingers to pry the end pieces up. Starting on the driver side, slide the rubber gasket that runs along the trim. You don't need to completely remove it, just enough past the brake fluid reservoir cover. Remove the plastic trim/cover covering the brake fluid reservoir. Remove the remaining plastic trim by prying from the top and gently removing with your fingers. It takes a little force to completely remove.

4. You should now have access to the strut's top mount nuts, but leave those secured for now. There are three each side. Remove the wiper mechanism on far end on the driver side. It's a 10mm bolt. This is so you can access the driver side upper struts.



5. Jack up the car using the car's jacking points. Refer to the owner's manual. Make sure you are on level ground, and once the car is in the air, BEFORE you start servicing your car, rock your car to ensure it's not moving. Not once did I have to go UNDER the car for this install. Be safe.

6. Remove the brake line and ABS sensor bolt from the front strut using a 12mm socket. Place the lines on the side as much as possible so it doesn't get damaged.

7. Remove the sway bar end link nut from the front strut with a 14mm socket and breaker bar.

8. Remove the two lower strut bolts using 17mm socket while using a crescent wrench holding the nut. Breaker bar would help with this as well. I didn't need to use PB Breaker or WD40.

9. Remove the three 14mm nuts holding the strut top mounts while holding the strut so it doesn't fall. Remove the strut from the car.

10. Install your new suspension in the reverse order.



Front torque specs according to TEIN.

- Front strut top mount bolts 50.0N-m
- Front lower strut bolts 240.0N-m
- Front sway bar strut bolt 74.0N-m

REAR

The rear install was a pain in the arse. From start to finish, I'd say it took about 4 hours for both sides.

You will need a sturdy pry bar/screwdriver and crowbar, and a second jack would be helpful.

1. Remove the 23mm nut securing the lower rear strut. I used a long wrench versus a socket/breaker bar because of the lack of space. The picture shows the bolt that the rear strut sits on.



2. Loosen the two 17mm bolts on the top of the rear strut.



3. Use a second jack to lift up and compress the spring. I positioned the second jack under the spring control arm. Remove the 17mm bolt on the spring lower control arm using a 17mm socket and 14mm wrench/socket on the nut. When the bolt is out, lower the jack supporting the spring SLOWLY until the control arm is at the lowest position, and the spring could be removed.



4. Remove the 17mm bolt and 14mm nut securing the TOP rear control arm. This would aid in removing the strut/shock from the lower bolt. If you don't do this step, it's going to be an uphill battle trying to get the strut off.





5. Remove the strut by using a pry bar or crow bar in a secure area under the lower control arm. Use caution as you move the control arm up to allow the strut to shift off.

6. The reinstall of spring and strut are pretty much the reverse order. I would use the second jack again after installing the spring in order to align the lower control arm bolt back in. The upper control arm bolt needed the spring compressed up as well along with the help of a screwdriver and crowbar. Keep in mind the spring's position on the spring pads (upper and lower). It has to match the indentation.

Rear torque specs according to TEIN:

- Rear strut top mount bolts 55.0N-m
- Rear lower strut bolt 125.0N-m
- Rear spring lower control arm closest to strut 73.0N-m
- Rear upper control arm 73.0N-m

 

Either upgrade or OEM. Steps are the same.

 

yes you brought up a good point that I forgot to mention. In order to counter the front sway bar torsion, I used my second jack to lift the suspension high enough to attach the end links to the strut. I know some might say it's better to have the suspension on the floor then tightening the end links, but I don't think my method is causing my noises or problems.

I'm still adjusting my height settings on the Tein Flex Z coilovers. Right now, I'm just about 1.5 inches lowered (total eye ball estimate since I forgot to take measurements before and after). The top of the fender is right at the top of my stock 15" tires on both front and rear.

 

You're right there isn't a lot of run tucked above the front and rear struts for EDFC or other remote dampening device. In fact, I'd have to remove the top bolts/nuts in order to made dampening adjustments which is very tedious.

 

I started using 8 clicks from hard in the front and 4 clicks from hard in the rear. That gave it a stock like ride, but was still too floaty to me. I like the ride to be stiff but compliant. I changed the damper to 2 clicks from hard in the front and 1 click from hard in the rear. This absorbes the bumper well without bottoming out.

 

Cool. Frankly go with 2-3 clicks from hard. Anything else it’s too soft. The springs are on the soft side already. I’m lowered about 1.5-1.75 inches which is perfect.