Honeywell OEM Overhead Toggle Switch Caps - Replacement Instructions & Part Nos.

[swvhhh]

As part of overhauling my Forward Overhead Panel, I decided to break the bank and use OEM Honeywell TN series locking toggles and changed the metal toggle caps to the rubber ones (Honeywell P/N 15PA90-6W).

They were quite difficult to remove as it is glued tight with Loctite. After a hundred tries and burnt fingers, I stumbled upon an obscure post in Chinese mentioning about a real Boeing Service Letter referring to the replacement of the metal caps.
(Original Post: https://mp.weixin.qq.com/s/_oDAXq6we5z1bLQDII9HCQ)

737-SL-24-179
All 737-100 through –900 aircraft

SUMMARY:
This service letter provides part numbers for the rubber switch tips used on the P5 flight deck overhead panel.

BACKGROUND:
Several operators have requested part number information pertaining to replacement of switch tips on flight deck overhead panels to avoid replacement of the entire switch due to lack of detailed part number data.

BOEING ACTION: 
Boeing has compiled this list of switch tips for most configurations of overhead flight deck panels. Two different tables are attached; one for 737-100 through –500 aircraft, and one for 737-600 through –900 and BBJ aircraft. Two types of switch tips are typically used: a P/N 69-44578-2 which is a long and thin tip requiring no adhesive to install, and a P/N 15PA90-6W tip which requires removal of the old metal insert on the switch tip prior to replacement of the metal insert/rubber tip combination.

SUGGESTED OPERATOR ACTION:
Operators are encouraged to use this Service Letter as a reference when replacing switch tips. The P/N 69-44578-2, which is a long and thin tip, requires no adhesive to install. It is a press fit switch tip. When P/N 15PA90-6W tips are replaced, the following procedure is recommended: Remove of the old metal insert from the threaded toggle-lever by unscrewing the old metal insert. When twisting-off the existing insert from the toggle-level, the toggle-lever must be anchored securely to prohibit any rotation of the toggle-lever. Note that elevating the temperature (~ 400F) of the cured Loctite will soften the material and aid in removal of the metal insert. Install the new metal insert/rubber tip assembly using Loctite 222MS or equivalent.

Included in the Service Letter is a nice list of OEM toggle switch P/Ns and what kind of rubber cap should be used for both the Classic and 737NG series!

After reading this, I took out my cigar torch and voila! The metal caps can now be removed easily. Simply use a cigar torch (or any butane torch with a nice tipped and consistent flame) and **heat the metal cap only** for about 8-10 seconds. Do not heat the shaft of the toggle because it will burn the electronics inside the switch housing. Then use a pair of pliers, wrapped with electrical tape to prevent scratches, to gently unscrew the metal cap out. If it is still stuck, heat the metal cap a little bit more. You should be aware that the metal parts of the switch will be very hot (400 Degrees F) so don't use your bare hands. I did not reapply any Loctite glue as I don't want to repeat the same heating procedure later.

[jfuenmayor]

Hi,
My overhead is completely populated with Honeywell switches. The metal is sort of
lock tighted with a very strong resin. The only way I could loosen the metal caps was using
a butane torch, other forms of heating simply will not work. Place the switch on some sort of heavy clamp then apply the torch to the cap for a few seconds until it gets really hot. If you want to know how hot, it charred the towel!!. Unfortunately this has to be made by feel, but they do loosen up. Immediately use either a forceps or a thick towel to unscrew the metal cap, if you wait too long it will harden again. I ended up using a towel.
And yes, at first, I burnt a couple of fingers too, nothing too bad. After the first two, it was a piece of cake.
Initially, purchased a big torch at HD but ended up using a small aeromodeler's torch which is much easier to handle. These little torches are also used in the kitchen to burn Creme Brulee and other tasks. Maybe your wife has one .
I then replaced the caps with the white rubber ones. I obtained them online but unfortunately I do not recall who was the provider.

I hope this helps.

JF

[jfuenmayor]

And one more thing I forgot to mention, wear a mask and stay away from the fumes!!

JF

[mickc]

Nice list, quite hard to find the correct part numbers unless you have the full.parts manual.

Just be cautious about posting official Boeing documents on the forum, they are quite sensitive to that at the moment

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