Author Topic: Broken Heater Control Escutcheon Stud Fix  (Read 2800 times)

Tomnistuff

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Broken Heater Control Escutcheon Stud Fix
« on: June 30, 2015, 20:50:35 »
While reinstalling my center 230SL heater control escutcheon, it should have screamed at me, "If you tighten me more, I'll break", but it didn't, so I did.  Of course I contacted Tom Hanson who basically told me I was several decades late with my request for a new piece.

My wife has always told me, “If you have a problem and the answer doesn’t come, go do something else.  The answer will come in a couple of days.”  She was right.  Here is a permanent solution that will work for either or all of the three escutcheon studs.

The one I broke was the small center one. Here's how I fixed it:

1.   I Cut off the remaining stud with a hack saw and ground (with my Dremel) the rest of the stud base slightly deeper than flush with the back of the escutcheon.  Then I put a layer of double sided tape, except where I ground down the stud base, to provide a slight clearance for step 3 below.

2.   On the two unbroken pieces, I put one layer of masking tape to build up the back of the escutcheons very slightly, so the notches and tabs between the three escutcheon pieces would still fit flush with one another.  It also helps to protect the paint on the radio plate.

3.   To replace the destroyed function of the broken stud, which is to bolt the heater control lever module to the back of the instrument panel sheet metal, I made an “almost-flush mount” conical washer to go with a counter-sunk M6 x 1.0 Phillips head machine screw by reshaping a normal washer.  As a conical shaping tool, I ground a large bolt end to the approximate correct conical angle and “coned” the washer by hammering the ID of the washer with the bolt point while supporting the OD of the washer with the chamfered socket wrench end of an appropriate sized socket.  A little selective grinding of the washer was also helpful.  The finished conical washer is about 14.2 mm OD to sit almost flush in the 13.7 mm ID instrument panel hole previously used by the stud.  It’s really close to flush but the “relief” in the double sided tape of the escutcheon provides an additional recess to accommodate the non-flushness of the washer, once the escutcheon is taped in place with the double-sided tape.  I suppose I could have used double-sided tape on the other two escutcheons as well instead of masking tape, but it worked fine with the masking tape because their studs are not broken.  Here’s a before and after cross-section sketch of the center escutcheon installed to show what the above words tried to say, plus a photo of the Phillips head machine screw and conical washer in place.

Tom Kizer
« Last Edit: June 30, 2015, 20:54:50 by Tomnistuff »
Apparently late 1966 230SL 4-spd manual (Italian Version)
Owned since 1987 and wrapping up a full rotisserie restoration/modernization.
Was: Papyrus White 717G with Turquoise MBtex 112 and Kinderseat
Is: Dark Blue 332G with Dark Blue Leather (5300, I think)

Jonny B

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Re: Broken Heater Control Escutcheon Stud Fix
« Reply #1 on: July 01, 2015, 13:12:59 »
Elegant solution. Excellent diagram by the way, clear, clean and easy to understand.
Jonny B
1967 250 SL Auto, DB 568
1970 280 SL Auto, DB 904
1966 Morris Mini Minor