How to know if control arm needs replacement?

I have a 2004 Prius with 200k miles. I've been told many times that the suspension needs work - specifically the shocks, need to be replaced. I believe that....so I finally invested in new strut assemblies. However, I was also told in regards to creaking and groaning noises - which I attribute to the brakes (sounds like rear brake groaning whenever brake pedal is touched) - that I should replace the lower front control arms. This makes no sense to me. I started replacing the front strut assemblies, and in the process was looking at one of the control arms. I don't see any problem. Boots seem to be intact, no looseness that I can feel in the ball joint. I don't hear any clunking sounds of loose suspension parts when driving. How would I know if I'm wasting my time and $ on something that doesn't need to be replaced? 200k miles seems to justify replacing the control arms, but how would I know that the mechanic isn't just finding unnecessary repairs?

 

I have already bought the control arms - MOOG parts - and ball joints from Olathe Toyota. But since I got in there and couldn't see any visible or audible problem, I'm thinking of returning them. Thanks for the replies and info guys!

 

Not yet, but intentionally have not driven it much since replacing the struts, while debating the control arms. There was some play in the strut fit. I knew an alignment afterward would be needed. The MOOG control arms and Toyota ball joints cost about $200 total. I will go ahead and put on the new control arms and then have the alignment done. It's good to have a lifetime alignment policy(!). I use it at least as often as every oil change.

 

Started on the drivers side, and already in trouble. The old control arm BTW was just fine, but the ball joint boot had a break in it. I'm following a how to video on YouTube, which makes this look EASY, but none of it has been easy, past removing the wheel. Is this video for real?! I have spent hours getting the old control arm and ball joint off, and the new ones can't get installed because the brake knuckle -ball joint - control arm parts are at least an inch apart. I have no idea how to close the space to get them together without disassembling the whole axle (which is what the manual would suggest doing in the first place!). I don't even understand what has pushed the wheel axel out an inch from the control arm in the first place. What is the disconnect with this Autodoc video that makes this look like a 15 minute job?

 

From what I am hearing, I'm not up for the passenger side unless I can see some actual damage to the old control arm! The drivers side arm was just fine. 15 years old, and looks great. I may not even do the passenger side ball joint if it has no visible damage to the rubber boot. So in reference to the Autodoc video, my mechanic said the axle can actually move out away from the engine during this work, and may need to be forced back inward to close the gap I have now between the brake assembly and the ball joint/control arm. The old ball joint took so many whacks to get loose, I can believe this is the problem. Good suggestion on the ratcheting tie-down. I have one and will try it out. I will try to take and post some pics.

 

Getting the axle back in place is not working out so far....may have to remove the brake rotor and get the axle completely loose from the knuckle assembly. The ratchet tie down doesn't seem to have enough force to compress the axle back inward.

 

Thanks again for the pointers! Ready to laugh or cry at this point. Yes, you were both right - spin the axle. This was easier to do than I thought once the lug nuts were loosely set on the rotor. It didn't even need any inward force. Lying on the floor and rotating the wheel assembly with right hand, I could visibly see the ball joint close the gap to the control arm, and used a Harbor Freight crowbar to hold the control arm down so the ball joint threads could get into the holes in the arm. Never felt anything loose or misaligned. I was trying to force the axle back inward when all it needed was spinning to the correct position. BTW, the mechanic thought this would never go together while I had installed the ball joint to the knuckle. He was 100% certain the parts would not fit back again unless I attached the ball joint to the control arm first.