1971 R/75 starter button | BMW MOA


I occurred to come across this thread by bigvic54 !

I recalled the a number of events whereas I used to be restoring a pair Slash 5s and did the “deep dive” into them, their perches and levers. The 1970, 1971 thumb buttons had screw & eye connections on the again of the swap; perhaps when the Brief Wheel Base Slash 5s received stretched to Lengthy Wheel Base, the screw & eye connections had been change to pin & socket.

Regardless, the electrical contacts are actually uncovered to the climate, notably because the “guts” of the swap face ahead and seize all the things !

Right here’s a typical preliminary disassembly image…

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As alluded to in prior posts, corrosion has severely affected the contacts ! The spring is what offers the purposeful “really feel” or “click on” to the flip alerts/high-low-flash headlight in addition to, retains the brass washer separated from the 2(2) prongs within the base. These prongs, contacting the washer, actuates the Starter Relay or Horn.

To disassemble the swap, that spring should be totally depressed, to increase the shaft out of the pocket within the bottom of the bottom, to free the E-clip… you Star Trek followers would possibly know this as, “the Vulcan Nerve Pinch”, by Mr. Spock, which causes intense ache and numbness of the thumb !

Whereas tears of ache are working down your face, thumb and fingers crippled, the E-clip rockets to the Black Gap within the store house ! Paul Glaves has it proper: finest to work in a dry cleaner’s clear garment bag !

DANGER: THERE IS THREAT OF PERSONAL INJURY OR DEATH ! DO NOT PUT THE PLASTIC DRY CLEANER’S TRANSPARENT GARMENT BAG OVER YOUR HEAD, ARMS AND TORSO ! THE SUDDEN RELEASE OF THE E-CLIP MAY INJURE YOUR EYES; PROLONGED EFFORTS TO SERVICE THE SWITCH(S) MAY CAUSE SUFFOCATION ! ONLY WORK WITH YOUR HANDS, FORE ARMS, ELBOWS IN THE GARMENT BAG; VIEWING THE SERVICING FROM OUTSIDE THE GARMENT BAG !

I consider the triangular male contact piece was silver plated brass initially ? The corrosive “bloom” I’ve seen, has the green-blue look of silver oxide.

I clear all of the elements with Security Solvent; use ultra-fine glass bead media at low stress, to blast the bottom and button; flippantly apply dielectric grease and, having “steeled” myself for Mr. Spock… reassemble. Carry out a purposeful circuit take a look at on the bench. Unintentionally, I discovered {that a} gentle coating of silicon dielectric paste, utilized to the Bakelite button, restores the great, subdued “charcoal’ colour with out shine…

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I observed a design change throughout the swap once they transitioned to the “pin & socket” electrical connections: the brass washer now had three(3) tangs within the interior diameter to grip the pivot shaft. Earlier, the 1972 R 60/5 proven in my banner, would routinely interact the starter even with the engine idling ! Hours of troubleshooting later, I discovered the early brass washer was free from the rubber cushion under it and… was welding itself to the 2(2) raised tags. When system voltage dropped and the alternator gentle illuminated, the Starter Relay sensed a “begin” situation ! I glued the washer to the ‘rubber child buggy bumper’ and made a notice to try this to all early switches going ahead.

Right here’s an image of all of the elements; serviced, painted, polished, re-plated with Cadmium/clear-Chromate; prepared for bars…

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Something Price Doing, Is Price Doing To Extra 🤪

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