Safety check - slight compression of spring via LCA

JHZR2

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I’m replacing bad ball joints on my 1991 mb 350sd, and one thing that I’ve read is to support the spring by putting a little bit of upward force on the LCA. I have one of those light HF aluminum jacks, and I’m trying to use that versus my big hein Warner.

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But any time, any angle I use to press up and compress the spring, the car lifts, not the LCA, and the spring doesn’t compress.

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I don’t know the absolute necessity of doing this. I guess in case the shock absorber fails?

But all the same, what am I possibly doing wrong? I know it needs to go up in an arc, but I’m not trying to heavily compress the spring or anything. Just get the tiniest bit of load while Im working there and manipulating the knuckle every which way…

What am I doing wrong?

Thanks!
 
What happened to the lower shock bolt? :oops:

I'm not a fan of those Merc springs that don't have shocks running through them.

What you're doing is the best you can do, that is, if you put the shock bolt back. You already have the spindle loose except for the LBJ and some brake sensor wires.
 
I don't know but that block of wood looks like it has a crack down the middle.

You need to get a copy of Mercedes WIS

I have the full FSM.

The wood split when I was trying to lift it up.
 
What happened to the lower shock bolt? :oops:

I'm not a fan of those Merc springs that don't have shocks running through them.

What you're doing is the best you can do, that is, if you put the shock bolt back. You already have the spindle loose except for the LBJ and some brake sensor wires.
?? They’re 12 point bolts.

Not changing the shock. Removing the steering knuckle is the current job…
 
Have you though about removing the ball joint nut and beating it out with a BFH. The jack is just to stop it from falling, that is one spring you don't want flying. Am I missing what you are trying to do?
 
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Yes the bolt that goes through the eye in the bottom of the shock is out-- put it back because if the shock comes off the spring can fly down.

It looks like the other side is held up by the tire, so the suspension is in a bind and the sway bar is going to try to make both sides move together.
 
Have you though about removing the ball joint nut and beating it out with a BFH. The jack is just to stop it from falling, that is one spring you don't want flying. Am I missing what you are trying to do?
I beat it out with a mallet and punch after removing the knuckle.

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I’m just trying to force the spring to be a bit compressed. Just a tiny bit. So the force is on a jack not just being held by the shock.

But when I try to jack up the control arm, the car lifts, the spring doesn’t compress.
 
I doubt you can compress that spring at all without lifting the car, you could always put a spring compressor on it to compress it slightly. Personally I wouldn't worry about it just keep going. IIRC you have the Klann compressor correct?
 
If it’s lifting the car, there is enough pressure on the spring. JMO
Yet the spring isn’t compressing at all. Ideally the car would stay on the jackstand and the spring would compress maybe half an inch.
 
I doubt you can compress that spring at all without lifting the car, you could always put a spring compressor on it to compress it slightly. Personally I wouldn't worry about it just keep going. IIRC you have the Klann compressor correct?
Yes I do have the klann compressor. I’ll just keep the jack as is down there in the way without lifting up on the car.

I managed to beat that ball joint out!

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i think you might have to lift with the jack out on the knuckle to get the spring to compress the way you want. for what you're doing the jack is just supporting the lower control arm and spring to keep it from possibly falling apart and it doesn't matter if the spring compresses
 
i think you might have to lift with the jack out on the knuckle to get the spring to compress the way you want. for what you're doing the jack is just supporting the lower control arm and spring to keep it from possibly falling apart and it doesn't matter if the spring compresses
Ok that makes some sense. Needs to be further out to be in an arc like the spring and LCA would move.

Thanks!
 
You will also find if doing this on a ramp like we use from MAHA then you would use a ratchet strap to secure the car to the ramp so that when trying to jack up the lower arm the car does not lift up.

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Nice Wilton vise. Glad to see the actual ball joint press as well.

The LCA won’t compress much, you just need enough compression to keep it in place while you do the work, and to get it back together with new balljoints.
 
Nice Wilton vise. Glad to see the actual ball joint press as well.

The LCA won’t compress much, you just need enough compression to keep it in place while you do the work, and to get it back together with new balljoints.
No compression is needed to get it back actually. I was glad to see that. Enough upward force on the knuckle to engage the taper and get 80nm of torque is key. Then enough downward force to get the UCA ball joint to engage that taper to torque to 40nm…

The vice is on my to do list for refinishing… not enough hours in the day… there’s a Parker and a Colombian there too waiting…
 
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