I need to replace the lower control arms on an 850 volvo, are any special tools required, and how difficult is it to do. I know it will need to be aligned after the job is done.

Just did mine. A couple hints:

Remove the bolts from the subframe mount first so you can swing the control arm around to hit it downward with a heavy hammer to remove the spindle.
Pry open the spindle clamp a little with a cold chisel and hammer.
Use PB Blaster on the spindle/clamp when removing.
Be sure clamp bolt is completely out. Hit the arm downward HARD, near the spindle to remove it.

You may need to carefully tap the new spindle completely up into the clamp. Be sure the spindle is completely inserted so that the bolt shaft keeps it from falling out, before tightening it.

Before tightening the new arm at the subframe, jack up the suspension while the car is still on the jacks to bring the level to that of where it would be if the wheel was on the car and full weight applied. This may be an easier method for you than trying to torque the subframe bolts while the car is on the ground.

I read the other replies...nothing to take issue with. I got my two replacement arms with new bolts on ebay from fcpgroton.com
For whatever reason, the "buy it now" price on ebay was cheaper than their website price. They were about $130 total for both (yup, only $65 each), including the shipping. I've ordered from them before and last time paid about $75 each. These are aftermarket units that look just like the volvo units. The prior units were scantech made in China, but these latest ones were unnamed, made in Germany.

Following the lead of my dealer from years past...the only time I've had the dealer do one....I did not get my front end realigned and everthing seems perfect anyway. When I had the tie rod ends and struts done last year I had a thorough 4 wheel alignment.
I did my right arm the other day...took one hour and 10 minutes. The car I was working on was a 1999, but came from Seatle...only has seen one year of salt...no problem get the balljoint end off the spindle. You do need to remove the bolt entirely before trying to losen the ball joint end, because as you'll see, the presense of the bolt locks it on...it's not just the "tightening" of the bolt that locks it on.
I'm a bad boy...didn't torque it. If someone tells me what the settings should be I'll do that during my next wheel removal.
I've also replaced these on cars that have been hanging around in salt country for several years...unbelievable how the ball joint end can be relentlously "stuck". Use penetrating oil and stay focused.

I recently replaced the lower passenger left contol arm on my 1994 850 wagon. I'd say it was relatively easy, a couple of hours or so. I used a Haynes manual as my guide, along with some common sense.Double check things to be sure nothing changed bwtween 94 and 96. Besides typical soctket and combination wrenches, You will need a set of metric hex wrenches that will fit on a socket wrench and also a torque wrench to set the bolts to the correct torque spec. the haynes manual lists all those #. The dealer wanted way too many $$$$ for the part so I purchased from autohuasz.com in arizona, very inexpensive and it was identical. remember not to use the old bolts over again, new ones come with the new control arm and don't skip the final torque with a torque wrench. good luck

Jackb's info is right on the money. Without a ball joint splitter and sledge hammer, getting the old one apart can sometimes be nearly impossible... even with them, it can often be a nuisance.

You need to get a bit more info about how to torque the new control arm... the final torqueing of the pivot points should be done with the suspension loaded, not with the wheels hanging, and it should be done to the proper torque spec... not a "guesstimate".

Good luck

Marty
'96 855T

Having a large air impact wrench is a tremendous help on any front end work as you're dealing with large fastners that are very tight. Lacking one, you need a minimum 1/2" drive socket set plus a long breaker bar for leverage and having a heavy pry bar handy doesn't hurt. Work on jack stands. You also may need a ball joint separator to get the old unit off although most control arms come with the new ball joint installed. A seized on old ball joint is a real challange. Check FCPGroton.com site (steering and front suspension) and have your VIN handy

jB