I installed this driver side mirror on my '47 3104 several years ago using the factory holes in the cowl. If I'm not mistaken, it came from JC. It seems to vibrate quite a bit at roads speeds to the point where it isn't very useful. Is there a way to 'settle it down'?
Balance your tires. Vibration in the drive train, tires, wheels, driveshaft, rear differential, etc, is usually the cause of mirror distortion.
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
How might one isolate the cause of the vibration? The tires are 16" radials with less than 5k miles. They were balanced when new. At that time, a bent rim was discovered and replaced. I'm running a SM420 four-speed with an open drive shaft (custom built and balanced). The rear differential is a 1956 3100 with a 3.90 set of gears. IIRC, the original three-speed on the floor, enclosed drive shaft and 4.11 rear end also caused the mirror to vibrate. The cab mounts were also rebuilt/replaced.
I was wondering if that's just the way it is, or if there is in fact a problem with a potential solution.
Old school rule of thumb. If you feel vibrations in the steering wheel it’s in the front end and if you feel the vibrations in the seat of your pants it’s in the rear end. If you are feeling no vibrations but the mirror shakes it very well could be in how it’s mounted.
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
There's usually some space between the outer cowl sheet metal and the reinforcement behind it. Maybe get some heavy putty and stuff it up in there. That would help stiffen up the cowl itself. That assumes you don't find anything else that might be causing it.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Does it increase with rise in engine RPM? Said another way, does it decrease right after you let off of the gas? Metal to metal contact in the overly complicated front engine mount will cause a lot of vibration. So will loose engine mount bolts.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
Thanks fellas, those are some great suggestions to follow-up on. The '47 has been tucked away for the Winter for the last month or so. Ah yes, Winter in Iowa, six inches of snow and -25 degree wind chill. I can't wait for Spring!
KEVINSKI-The mirror itself seems secure and without any loose parts to include the glass. No passenger side mirror and the rear view mirror on the windshield doesn't seem to vibrate.
Martin-No detectable vibrations. Surprisingly, a very smooth riding and nice handling truck at all speeds. It even goes down the road straight!! I'll have to re-check the mounting.
Kevin-I'll give that some thought when re-checking the mounting.
bartamos-I believe it did. Since purchasing the truck in 2013, I've been chasing down rattles, squeaks and clunks. I'm down to the mirror vibration, I think........
Carl-Yes, it does seem increase with engine RPM and decreases when off the gas. The engine mounts (front & rear) are new and in good shape. I attempted to install the front engine mount as per the shop manual. Maybe that's the culprit? I'll retrace my tracks on the front engine mount.
