Another Old Guy

Hello.

I am the new owner of a 1992 300E sedan as of last week. The vehicle is in great shape, with only a few minor issues. I am hoping someone on the forum can help me understand one of these issues.

The previous owner sold me the car with the antenna severed at the juncture of the mast collar threads and body (see figure 2). The unit is a Hirschman (see figure 1). I procured a replacement mast and began the install procedure. However, all my attempts failed as the nylon stop at the bottom of the mast would not pass through the vertical tube exiting the motor assembly.

Pulling the motor unit apart for inspection revealed no internal anomalies, but it was apparent that



· The threads at the top of the vertical tube are badly damaged and appear to be 1.25 mm (unable to get a thread gauge in for a definitive measurement – will get some metric bolts tomorrow)

· The mast threaded collar threads appear to be M10 x 0.5, which obviously can’t mate with the top of the vertical tube

· The nylon stop diameter at the bottom of the mast is larger than the minor diameter of the vertical tube’s threads

· A borescope of the vertical tube from bottom up shows a strange protrusion running up one side of the tube. It looks suspicious to me

So, it’s not possible to get the nylon stop past the gummed up threads in the tube, and these threads can’t mate with the mast locking collar even if the nylon stop could seat at the bottom of the motor.





Suggestions?

Plutoe

sounds like you are not using the correct install procedure-------check MB EPC for the correct part number and MB WIS for the correct install all else is HS

Another Old Guy

Install procedure is correct (and I’ve done this numerous times on other vehicles). It’s a physical interference problem.

checking the sources you reference is an excellent idea. Can you point me to their location?

wease206

Get some 400 grid sand paper and sand down the plastic not ti much do little at little a time. When I did mines I count 10 full circle and it will slide right in the hole and you can insert the in to the housing

Another Old Guy

Sounds like a plan