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<useful info about e36 ball joints>

re: a week ago i said i was getting balljoints replaced under warranty

I learned something, the independant bmw garage (where i bought new tires)
looked at the balljoints and thought they were bad, 1/8" vertical play and said
"get them replaced under warranty".  Later...The authorized bmw dealer said
"the joint is ok, because no side play" and showed me another '92 model which
had similar vertical play.
I wasn't convinced until we looked at a brand new balljoint.

Turns out the balljoints were ok, it took some convincing, but in the process
I educated myself and a couple other mechanics. 

The e36 balljoints are unusual in that the lower part (socket part) is not
connected directly to the lower control arm, rather it is suspended in
rubber surrounded by a metal cup. The metal cup is the part which connects
to the lower control arm (i think its pressed into the arm).

Only after examining a brand new balljoint (by using large channel-lock pliers
to squeeze the ball part into the socket) we discovered that it doesn't take
much force to compress the rubber, and what looks like "balljoint looseness"
on the car is really due to the rubber being compressed.

I guess its nice having an extra 'shock absorber' in the system, but the
rubber mounts support the full front weight of the car, so keep an eye out
for cracks in the rubber! ,a mechanic told me that they do crack. 

All this relates to an earlier problem of the car tramlining, which appears
to have been cured by new tires (yoko a509). I was told by an autocrosser
that the original goodyears i had, when worn down, exposes a harder rubber
which no longer 'conforms' to irregularities in the road, thus tramlining.

- -Frank Schulz

'92 318is 44Kkm   'tomorrow, out of warranty.. sob'