Mr Fufu

Hi Folks!

The turn signals on my '67 are acting up.

It started with the blinker not working on left turns. I discovered that the left front turn bulb wasn't lighting up.

So I replaced the bulb. But, that wasn't easy. I found that the socket was corroded due to moisture getting in. To remove the bulb I had to smash the glass globe and pry the base of the bulb out with needle-nose pliers. I cleaned out the corrosion as best I could (it's hard to get in there) and installed a new 1157 bulb. I think the contact at the base of the socket isn't great because I had a hell of a time twisting the bulb around until it would make proper contact and light up.

So far so good. But now I notice something new. When I put the left turn signal "on" the flasher goes slower than when I put the right turn signal "on". However, when I push in the 4-way flasher button all lamps flash at the faster (normal) rate.

Is my "slow" left turn signal caused by a (still) poor contact in the bulb socket? Are these sockets known to give trouble? And, is there a fix for the poor contact issue, other than replacing the entire socket assembly?

Thanks for your tips/advice.

denson

most likely a poor ground to the brass or cadmium plated cylinder-shaped barrel that the bulb twists into...i have soldered an extra wire to the brass ones before (1957 Belair, 1960 Corvette, and 1962 Impala) and hooked the new wire to a good frame ground.

Mr Fufu

Thanks Denson.

I'm going to use some stainless steel wool to remove the corrosion from inside the lamp barrel. Hopefully that'll help. Otherwise, I'll have to solder an extra wire, as you suggest.

Cheers!

dkleather

Put some dialectic grease on the base of the bulb before inserting it into the socket. It will slide and turn easier and should make better contact. Dave

Mr Fufu

Good tip Dave!

Anything that would make the bulb turn easier is a good thing. Thanks again for your tip.

Cheers,

Alex

dplotkin

I think it more likely the bulb. The original type of flasher unit is thermal and its flash rate is a function of the bulb load (current draw). If you change the bulb on the other side to the exact same bulb you just installed you will likely have the same rate between them. You could also try another flasher, the electronic versions don't care about bulb load and would work fine but would be decidedly un-NCRS like.

Could be yesterday's 1157 is not exactly the same as today's in terms filament resistance. I've run into this.

Dan

Frankie the Fink

There is an old trick I have to perform time-to-time on later bulbs. Take a soldering iron and add solder at the base of the bulb at the two contact points. Make a healthy little bubble of solder....then file them down flat, do a test fit, file some more, repeat until you get a nice tight fit, with good electrical contact while still allowing the bulb to be pushed and rotated into position....

Mr Fufu

Hi Dan,

You were spot-on about the flash rate being different depending on the age/make of the bulbs!

I first changed the left bulb and noticed the difference in flash rate compared to the older right side bulb. So I took your suggestion and changed out the right bulb for a new one identical to the left one.

Now (voila!) the flash rate is the same! Your explanation made total sense, so thank you for teaching me something new.

Alex

dplotkin

The pleasure is mine.

Incidentally incandescent lamps get dimmer with age not because of degradation of the filament's ability to illuminate but rather the vaporization of the filament over time that deposits itself on the inside of the bulb and obstructing light (darkening).

The problem you had was manufacturing specification differences between lamps. It doesn't take much, the flasher is very sensitive to the current draw of the lamps.

Dan