I was thinking that the ball joint was part of the control arm but evidently is not in this case, it bolts on instead of being pressed in or non-replaceable. I would probably go a head and have your mechanic replace that if you have never replaced it, it probably has to be removed in order to get the control arm out to replace the bushings. In this case, it probably won't be any more cost effective to go for the whole control arm vs just the bushings. I would only have the control arms replaced if there is bad rust of signs of stress.

How many miles are on the car? If you are having a mechanic do the work, you may want to look into replacing a few more things while he's in there, such as the upper control arm & ball joint (I think this is one assembly), tie rods, shocks, and spring pads. Basically anything that is a wear item. If he's an honest guy your labor rate wouldn't be too much higher because a lot of these parts must be removed or partially removed in order to get the lower control arm out. If this is a car you have any intention of keeping for a while, it might make sense to go ahead and do the work now as every time you have a mechanic work on the front end they would have to remove some of that stuff.


EDIT: I see your signature says the car has 87K miles so none of that should really be needed unless it looks like it. Why are the bushings being replaced?

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.