Lotus Elan

Brake switch thread size

PostPost by: William2 » Wed Apr 02, 2014 11:59 am

Can anyone tell me the thread size of the electrical brake light switch off an Elan S4. The new switch I have doesn't come with any nuts?
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PostPost by: lotusgagne » Wed Apr 02, 2014 8:44 pm

There should be no need for a nut, the switch simply screws into the tab welded to the pedal box. At least that is the way mine is, I know, I just broke the plastic switch while fiddling with the pedals and got a new one from RD, it fits perfectly...

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PostPost by: CBUEB1771 » Thu Apr 03, 2014 12:55 am

The brake lamp switch for the later Elan +2 is threaded 1/2"-20 UNF. The part number for this switch is A036 J 6154, indicating first use on the Elan so I assume that the late +2 and the S4 use the same switch. Unfortunately my workshop manual and service parts list for the Elan do not cover the later switch at all so I am left to educated speculation. On the +2 the switch threads into a nut welded to the pedal box and no lock nut was used by the factory. This always bothered me because that left the electrical wiring to the switch as the only "locking" device that would prevent the switch from rotating out of adjustment with respect to the brake pedal. I made a very thin lock nut to keep the switch in place after adjustment. The lock nut had to be thin ( about 1/8") to avoid using up too much of the threaded length of the switch which is needed for adjustment. Obviously the lock nut can't be tightened much as the plastic, fine threads of the switch body are easy to damage. I hope this helps.
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