Brake light sender

[Steve Little]

Interesting thing happened on my way home from a party a while back. I was riding my 51 Pan home and had to travel through Melbourne to get there. Everything was fine while I was belting along the freeway but as I started to get into the built up areas I would roll off the throttle to decelerate with the traffic and eventually stop at the traffic lights. As soon as I got to a stop the bike would let out a whopping backfire that sounded like a shotgun. I would have to slide out the side stand and kick it into life, which it did on the first kick
This became standard routine for about about 6 sets of traffic lights. After the first couple of shots, I pulled off and had a quick look for loose wires or obvious problems but could see nothing. I got to one intersection where I was part of 4 lanes of traffic. I was keeping near the footpath in case the bike would not start. As I rolled to a stop I heard the engine do that sound of dead engine brake, so I rolled up on the footpath.
I kicked it. Nothing. I kicked it again and it let out a real cracking BOOM and started. I slung my leg over the bike and looked at the traffic to see if it was moving yet. I saw the head of a young teenage girl slowly come up from a crouched position in the car closest to me. She was peeping over the window for the source of the sound and I'm guessing she thought it was a gun shot. Sad sign of the times.
I got home, threw the bike in the shed and thudded the roller door down. I'd had enough of motorcycles for a bit. I got to the search, and destroy, mission a few days later. It turned out to be the brake light sender,shorting from within. I went to my box and got a good one and got rid of the problem.



Been collecting these for a while and need one for the bike I am building so I tested the shooter to see what was happening. I decided on open heart surgery and pried back the tangs holding the bakerlite plate in place.



There was nothing obvious but a little more investigation saw the hole in the bakerlite plate was flogged out. This was allowing the rod to skew sideways and dead short the spring to the back of the electrical connection. Time for some corrective measures.

[Steve Little]

The shaft is 3/16” diam. The hole was flogged to an elliptical shape. Even though the worst of the shape was 3/8”. I determined that I could not drill a corrective hole bigger than 5/16” because the brass terminals have an inside distance of 11/32”

Put the bakerlite disc in the 3 jaw chuck and drilled the hole to 5/16”. Then put a piece of Delrin round bar in lathe and turned up a 5/16” bush with a 11/32” shoulder to sit against the bakerlite.







Then drilled a 3/16” hole through the center for the shaft.




Cleaned the body and internal parts within an inch of their lives and got ready to put it all back together, but had one last look at the body. I could see that the mounting bracket has taken a hit at some time in it's history. The distortion of the mounting bracket forced the brake sender to point toward the oil pump, instead of pointing at the brake lever.




This was the cause of the flogged out hole. The direction of pull on the shaft was causing heavy rubbing of the shaft on the softer bakerlite. Causing the elongated hole.

[Steve Little]

Time for a bit of pressing in my little garage press. There was a dent in the side of the body (most likely the point of impact for the distortion) so I used a socket of appropriate size and gently pushed it into the drum of the sender body. This took most of the dent out. Time to correct the distortion of the backing plate. I refitted the socket in the drum as support and then got my mini max socket set and picked another socket and short extension bar and gently corrected the bend until it was nice and flat. By this stage I was running on maximum focus and forgot about pictures



All flat now. Assembled and ready for fitment to the bike.

[cdndewey]

Interesting fix...well done.

[Shaky Jake]

Yes, well done.


Kevin.

[Rooster]

Extremely nice work. It always gives me great pleasure to see damaged parts and pieces given new life. I have one that also has a bent bracket. Have been looking at it for months considering different methods of repair.
I've never pried one open, so I appreciate the photos, Steve- and the considerable effort it takes to post them.

[Steve Little]

Thanks. My first time in there as well.
Thought I should amend my ways, so I got out the rest of the brake light senders and did a picture run for visual reference.







After massaging the bracket to sit flat on the drum, I left the press on it and used the top socket as a visual to square up the vertical bracket with a little hammer.

This is a better direction for the brake light sender to point.





I was able to complete and assemble another one but need to find some new springs for the others. Two of them had springs that had lost their “set” and I am guessing they sustained considerable heat through a short.
The brake sender in the middle only had one tang remaining, and it broke off at the slightest touch of my screw driver.
I bought all of these on eBay. The guy who originally owned this, had an inquisitive mind, but obviously lacked touch. The bakerlite disc is almost gouged beyond use. I bet his bike would have been interesting to look over.
I modified an old ¼” wide screw driver and sharpened it on one side so that it would wedge under the tang. Once it lifted high enough I used some low profile pliers. I don't know the correct term for them, but the Snap-On guy bedazled me with them and my wallet always felt violated when he left his truck. But I always grabbed a hand full of lollies as I went down the steps.
When I think about it, those little lollies were worth about 10 bucks each.

[Rooster]

Thanks for the pictorial, Steve. I may have to give it a go. I have some interesting pliers that should work well, but lack the Snap On brand...