E36 m3 3.0 and 3.2 front arm balljoint replacement guide

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harry_p
Posts: 1480
Joined: Thu Jul 31, 2008 9:09 pm
Drives: e36 m3, e30 m3, mk2
Location: Norfolk

E36 m3 3.0 and 3.2 front arm balljoint replacement guide

Post by harry_p » Fri Nov 08, 2013 7:35 pm

This is a brief guide for a method which I have found works well for changing the solid balljoints as fitted to e36 m3, and bmw e30 lower front arms. As far as I know, the outer joints in normal e36 arms are not replaceable.

Tools required,

17mm socket
19mm socket / spanner
21 / 22mm socket / spanners
Ball joint splitter
Electric saw with metal blade or decent hacksaw
Angle grinder with grinding disk
Lump hammer
Small bolster or large cold chisel
Large socket to sit flat on the rim on the back of the new joints, approx 36mm

And of course, the new joints. You'll need two inner, and two outer joints for a bmw e30. Make sure ou use good quality joints from febi, lemforder, meyle or similar. Its not a job you'll want to repeat for a good few years.

First step, remove the arm from the car, this should be fairly straight forward. On my car there was a 19mm nut on the outer joint, two 17mm holding the rear bush bracket to the shell, and a 22mm nut on the top of the inner joint. Please note, the inner nut is a right pain to get to and will almost certainly need an open ended spanner and a lot of swearing.

Once all fixings are undone I use a simple fork type separator to free the arm from the hub, and then from the subframe. A few good blows and out they pop.

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Turn it over and you should see this,
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Mark the position of the dimples in the base of the joints on the arm, I used a 4mm drill just to mark the surface, but paint or a scratch mark will work fine.
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Next, grind the protruding rim off the back of the balljoint,
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Turn the arm over, use a small flat blade screwdriver or pick to remove the small spring from the base of the rubber boot
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And remove the boot
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Give the stalk of the joint a whack and due to the previous grinding, the bottom of the joint, and the main guts should pop out.
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Leaving just the outer shell in the arm, and you can see the reason for marking the orientation of the joints, they have a lot more movement in one direction than the other.
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Use a saw with a metal cutting blade to cut two slots into the shell, as deep as possible without touching the actual arm. I have found two slots works best to weaken the shell and give you something to hit against.
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I hit the piece between the slots both inwards and downwards to both break the shell free of the arm, and down and out too.
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A few well measured blows with a lump hammer and suitable drift, and the shell should come out. It will be in pretty tight!
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Line up the new joint with the marks you made earlier,
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And find something suitable to knock the new ones in, I used a 36mm 12point socket, but its a fraction tight and can mark the raised rim if you're not carefull. A slightly larger or a modified socket may work a little better. Like a bearing, well measured taps to knock it in nice and square at the start is better than just bashing the hell out of it.
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Knock in until the base is flat against the arm.

I've only shown the outer, but the inner is exactly the same, you just have to be carefull to make sure the much longer stalk doesn't hit the vice or bench you're using as you knock the joint through or you'll damage the joint.

Job done, arm ready to go back on,
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One thing to note, the original inner joints on my arms had 22mm nuts, the replacements had 21mm ones which caused some confusion at first.

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