I finally decided to rectify the os front suspension knock my 123 series diesel has had since I bought it 6 months ago.
Three garages failed to find the source of the problem and as I cant detect any play anywhere with limited leverage of crowbar I began replacing parts!
Upper wishbone and bushes, lower wishbone bush (the one under spring plate). This made no difference whatsoever so I am now considering replacing the guide rod chasis mounting and wondered if anyone has had success with this and if it would produce a knock if worn?
Or.. could it be steering related, the arms seem ok?

Worn guide rod (some call them track rod) mounts can certainly cause something like a pop or knock.

It tends to start out with a pop when you apply the brakes or slowly roll over an expansion joint or pothole. But it rapidly gets worse from that point. On my 1982 300D, one side got so bad that you could see and feel the car flex to that side as you came to a stop. Release the pedal and the car would jump straight again.

A visual inspection of the mount can tell you a lot if you peel back the rubber boot a bit. Any indication of rust and its GONE.



Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

Cheers Ken, didnt know you could see behind the boot, will have a look right now.

It looks like new behind there?

thats a good spot for a clicker...track/guide rod mount.

might be a ball joint
Jake