DIY: Rear strut replacement write-up and photo dump

While my 2007 Prius Touring is down for a hybrid battery issue (see 2007 RTOD), I took advantage of having the rear interior gutted to drop in a new set of rear struts. I chose a set of KYB Excel-G 341322 purchased from RockAuto. These are stamped Made in Japan on the strut assembly. I installed a set of KYB struts in my Honda Fit based on their price and availability. The Prius is nearing 200K and is new to me. Ride has been soft and spongy feeling, no excessive bounce but not as tight-handling feeling as I am accustomed to in Hondas.

My guess was these were still the original factory Touring edition struts with the 2 color band markings on them. Both originals were marked TOYOTA ZB14 48530-47041 KYB on the tubes. I watched this video as a guide and followed the factory service and Bentley manuals as reference and torque specs. The Prius was placed on jack stands with the rear tires barely off the ground. I used a floor jack and a block of wood to support the center point of the beam axle. There were two 14mm nuts retaining the strut mount to the interior and a 14mm bolt holding the mount from underneath that threaded into the welded nut on the inside. These were removed and then I used an air impact to remove the 19mm nut holding the strut to the axle. Both original struts compressed smoothly with firm constant pressure but neither rod returned after release. While no visible signs of leaking was present, the fact that the rods don't rebound indicate the old struts were long expired.

Comparing the original strut to the new KYB 341322, the tube is a few mm thicker than the new replacement. KYB did not list a different part for the base and touring models. For the spring compressor, I used a set of Performance Tools W80559 that are heavy duty and manufactured in Taiwan. I chose these over the other common sets which utilize weak looking pins to retain the springs. These spring hooks are low profile and hooks onto the coils easily. The rear springs are not under heavy tension and easily compressed using both working in tandem, just enough compression to allow the coil to rotate from the spring perch. Then carefully loosen the 17mm nut from the rod.

I was able to reuse all the original pieces which consist of the 17mm nut, a flared washer, the mount, a dust cover with a bump stop, the rubber pad, and coil spring. The rubber pieces were still intact and appeared serviceable. I cleaned and removed any excess debris and applied a light coating of silicone grease before reassembly. The only challenging part was torquing the top 17mm nut to 41 foot pounds while using a 6mm hex to keep the rod from spinning. I used a 17mm flare nut crowfoot attached to a 3/8" extension to a torque wrench. It was somewhat difficult without the aid of a bench vise to hold up the strut.

Reassembly was pretty straight forward. The 14mm nuts and the 14mm bolt are torqued to 59 foot pounds. These were done while the axle was supported. Both manuals called to lower the car to the ground and bounce the car a few times then torque the 19mm nut to 59 foot pounds while the TRQ video did not. I elected to follow the manuals and torqued the nut with the car lowered to the ground.

Overall, I think this was a straight forward intermediate DIY project and can be done with common tools and it can be completed in half a day's time by a single person. Aside from the common set of metric sockets and wrenches, you will need a decent 1/2" or 3/8" torque wrench capable of 41ft/lb and 59ft/lb. Its also good to have a nice 1/2" breaker bar and will be helpful if you have a strong impact to remove a tight or rusty 19mm nut. You will need a spring compressor unless you install the complete strut-in-a-box set.

 

Thank you.

While there are several yt videos on the topic and good reference manuals out there, I guess I'm more old school and thought a write-up to summarize my experience and capturing detailed pictures could be helpful to other fellow DIY owners. It also helps that this 18 year old Prius isn't heavily rusted out to be able to easily do this at home. This would be my third car that I've touched struts in 12 months without any prior experience working on suspension work. I worked on a 1996 Corolla using a full set of FCS complete strut/coil set last year and played with this spring compression tool on the old scrap to figure out how it worked. Read up on how dangerous coil springs are to work with but with lighter vehicles, the work IMO isn't all too bad. Perhaps I should have installed new coils as suggested but I didn't see any on RockAuto and mine weren't too rusted out or appeared broken visually. Once I get the Prius back on the road after I deal with the traction battery saga, I can tell how the new struts feel. My future plan is to eventually replace the front struts on the Prius.