PowerFlex Rear Subframe overhaul 2001 XC70

[Chrisd]

So I decided to take a high mileage, 240,000 2001 XC70 with every bushing and moving part in the rear sub frame and rebuild it. It seems somebody had a right rear wheel balancing issue and they didn't notice, over time the vibrations, vibrated everything to pieces. I decided to give the PowerFlex Poly bushings for a S60 AWD a try. The S60 AWD shares all the same part numbers as the XC70, so off I went and purchased them through Viva. I know that the XC70 weighs about 500 Lbs more than an S60, and that was a concern, but it turns out not to be an issue.
Removing the sub frame is a lot of work, the drive shaft was a little loose at the middle bearing as well. And the exhaust fell apart which added to the cost. The final drive had its seals replaced, take note of the depth of insertion before you remove the old ones. All old bushings on the rear subframe were removed by drilling a small hole right next to the edge , providing some "relife" and then a nail or other object pushed the edges inward, after reliving the pressure most bushings just pushed out with a little persuasion. This way the aluminum subframe bushing holes didn't get damaged. Most bushing holes were corroded inside, I purchased a 15.00 dollar hand sand blaster that cleaned stuff off nicely.
All of the replacement bushings, except for the upper control arm, are 2 piece bushings and were not an issue to install. The upper control arm bushing which is also on the bearing support was pulled in by using extra washers and some threaded rod, it felt like a hand ball joint tool could have been used as well, getting the upper control arm bushings out wasn't really all that difficult either.
Remember to note the orientation of everything for reinstallation. Another added benefit of the Powerflex bushings was setting the ride height, you don't really have to worry as the PowerFlex bushings will rotate. But the upper control arm needs to be set and I found doing this before the subframe goes back in easier than playing with it after its reinstalled.
I set the ride height at about 5 and 1/2 inches from the bottom of the rear subframe frame mounts to the center of the sway bar hole on the upper control arm. Vida calls for something like 117 mm from the top of the subframe mounts, but I think vida is wrong on this one. Anyways perhaps checking some point while the XC70 was still together might have been a good idea.
We did have a few moments with the PowerFlex bushings with toe in issues initially, a few shims were pushed into the front stays, the front links to add some pressure to the bushings, this cleared that issue right up! The XC70 is very sensitive to the correct toe in the rear. But after finding a better alignment shop I am very pleased with the results.
I'm not sure I would spend the amount of time replacing the rear subframe on a vehicle in great shape, I would describe this job as a big plus, I'm concerned about the longevity of the poly bushings, but for a lot of work it was worth doing! It wasn't a dramatic improvement, and sometimes there is a slight kind of elastic feel, but the XC70 is now a pleasure to drive as compared with stock. Stability and cornering are considerably better! After the bushings were done I added the ipd front and rear HD sway bars, and that is also a great addition. The ipd bars bring a XC70 to the vehicle it should be. I can corner and change lanes with much more stability and control with only a slight harshness in overall ride comfort. I should have done this long ago. All in all the PowerFlex overhaul is a great improvement, a lot of work, and remember the rear alignment is very important. The rear wheels have a visible front toe in that you can see, takes a bit of getting used to IMO. If you set the rears to 0 toe in, to get your vehicle to an alignment shop, the car is downright unstable. Keep this in mind. The factory settings for the rear work just fine. Overall I'm very pleased with PowerFlex and the way things turned out!
Any questions and I'll try to help out!

[Astro14]

Great write up.

Thanks!

Replaced every bushing on my 1990 4Runner with power flex polyurethane. Old bushings on that truck were quite difficult to get out. No amount of drilling worked, I eventually burned them out.

The XC is at 209,000 now and running perfectly. I replaced the entire front end, and the rear shocks, at 160,000. Good to know that I can rebuild the rear as well.

Cheers,