replace lower ball joint
 

can you replace lower ball joint without taking the wheel hub off? doing brakes and replacing rotor so replacing bearings. probably should do lower ball joints but would kinda like to get this project back together. hate to redo bearings and then have to do them again when / if i want to do lower ball joint.

On the 116/123/126 chassis the entire spindle needs to be removed from the LCA and UCA connections and then is usually worked on in a bench vice. I'm pretty sure that the hub rotor will be in the way doing that and definately will make things heavier and more awkward doing anything.

If you're either cleaning/re-packing or installing new bearings now you would only need to in the short term future reset the bearing end play after removing the hub/rotor to R&R lower ball joints, not re-clean and re-pack the bearings.

+1 on removing the steering knuckles. Much easier to R&R the lower ball joint with the knuckle off the car. Not much more work than trying to do the repair with the knuckle on the car.

other than the fact that the rotors are worn below specs i wouldn't even be doing the bearings but figure might as well replace 24 year old bearings since i'm taking it apart for the rotor. the grease wasn't a bit dirty, still bright red. races and bearings still look like as bright and new as the ones i'm putting in..

wonder why MB did the rotors like they did. what a pain that they're bolted to the hub from behind like they are. i was really afraid i'd have a hard time getting the allen bolts off after all these years, but not a bit of a problem and with a few gentle hammer taps the hub and rotor separated no problem.

there is a bunch of grease caked around the lower ball joint, so i'm pretty sure i need to change those out as i'm assuming that grease is from a hole in the ball joint boot, but haven't really checked yet

just trying to get the old gal freshened up after all these years. with only 93K it's really time that's the enemy not use.

For all practical purposes I'm of the mind that it would not be possible to remove the old ball joint from the spindle still attached to the vehicle. I've never seen a tool specifically designed to remove these ball joints from position, on the vehicle. Someone may be able to construct a hydraulic or screw powered tool but I've not seen one yet that is specifically designed for this 116/123/126 spindle.

That unfortunately leaves a hammer and punch of some sort, how anyone could position a punch and then swing a hammer with the accuracy and force I've observed is often needed is beyond my imagination! Not to mention you'd be hammering upwards against the spring and shock and suspension dynamics!

I remove the spindle, clamp that in a huge bench vise I have, the punch/drift I use is an extremely strong and well made German steel socket about 1 1/2" in diameter to which I've welded an 18" steel rod handle, holding the punch in position on the ball joint's bottom side (now face up in the vice), I can really swing a 6 lb machinist's sledge with a full arc. Usually two or three blows like that will pop the old ball joint out, but there have been a few that took ten blows also, and a couple that only surrendered after being partially dissected first.

I own two of the ball joint installation presses one a SIR Tools which has an update modification of a steel plate to reinforce its spine and an AST Tool model which is manufactured originally out of thicker steel plate than the SIR Tool. The amount of force the turning screw exerts is impressive and virtually every bit is needed to install these ball joints in the spindle. I fact I'll try to find it but, I have a picture of ball joint press that was mis-used where the ball joint itself was not started straight and square to the spindle, the person using the tool failed to observe that fact, cranked on the tool attempting to force the crooked balljoint anyway. The ball joint could not be forced into place and in attempting to do so actually bent the 1+" thick steel spine of the tool, and this was an official MB # stamped tool not an eBay special!

actually i was thinking one could remove the steering knuckle with the hub still in place so you wouldn't have to remove the hub and open the bearings again.

You can do that, but I'm pretty sure that the rotor will prevent access to the underside of the ball joint where it sits in the "cup" of the spindle. I'm almost certain that for the same reason there is not enough room to use a screw type ball joint installation press tool and I'm pretty sure it will be impossible to get the spindle with the hub and rotor still attached positioned in an H-frame type press to remove or install the ball joint. So you can take the spindle off with the hub and rotor attached but you wouldn't be able to accomplish much concerning the lower ball joint once you did.