C2 1965 Headlight Motor Rebuild

[George C.]

Re: C2 1965 Headlight Motor Rebuild

Duke,

I finally got the two outboard pivot balls off the shafts tonight, lots of liquid wrench, a little heat, and a pair of water pump pliers. The buckets, and brakets are now cleaned and reday for reassembly. Tomorrow I can tackle the motors, I ecxpect the gear boxes are cruddy and dry, and probably nead new drive gears as you suggest. I found a couple pretty good drawings in the catalogs so I am about to tackle that job. Is white lithium grease the right way to go for both the bucket pivots and the gear case, or do you use something else?

Thanks,

George

[George C.]

Re: C2 1965 Headlight Motor Rebuild

Bill,

Yes, from all the answers I have received here, I am hopefull that the motors are good, and I just need to clean, relube and probably replace the drive gears.

Thanks again for your input,

George

[George C.]

Re: C2 1965 Headlight Motor Rebuild

Donald,

I am going to try it myself, and yes I am going to do them both. I have received alot of good information here, and from the way they worked in the past I am counting on cleaning, lubrication and probably replacing the drive gears.

Thanks again,

George

[Duke W.]

Re: C2 1965 Headlight Motor Rebuild

Yes, good ol' white lithium should be adequate for the job, but it dries out over time, so make a note to pull the assemblies out, clean and regrease them in 10 to 12 years.

Duke

[Craig S.]

Re: C2 1965 Headlight Motor Rebuild

George - just make sure you slip the armature out of the housing and polish the shaft with crocus cloth plus lube the spherical oilite bearing in the back by the handwheel. This is the area that seizes frequently, and may need attention as I described in ohter posts recently per the advanced class I took from Steve Hack in Bloomington...Craig

[George C.]

Re: C2 1965 Headlight Motor Rebuild

Duke,
Now the fun begins, I dissasembled both motors one at a time keeping things seperated, neat and tidy while everything got cleaned and relubricated. I decided to go with high temp wheel bearing grease for the motors as that is what appeared to be used before. The drive gears as you suggested are only worn on one side, and worn very little at that.
I have some new questions for your technical expertise. How do I install the gears to be sure they are timed to run on the shiny new surface? I expect it depends on where I start, buckets open or closed. Next what do the points in the motor do, do they control the direction of the motor? Last the speed adjuster seems to just apply pressure to the armature shaft, how does that control speed and what would be a good beginning point, I have not touched them as of yet.

Thanks as always,

George

[Duke W.]

Re: C2 1965 Headlight Motor Rebuild

I would not recommend wheel bearing grease. It's too gummy. Do this test. Place a small dab of white lithium grease between the thumb and forefinger of one hand and wheel bearing grease between the thumb and forefinger of your other hand. Then rub them. You will probably find that the wheel bearing grease quickly becomes gummy and will have more friction. Wheel bearing grease is for wheel bearings, which get hot and are highly loaded. White lithium is a good general purpose grease for lightly loaded geartrains such as the headlight motor and windshield wiper transmissions.

For reference the spiral gear that is part of the armature shaft is called a "worm" and the gear it meshes with is called a "worm gear".

It's been awhile since I did this job, but I recall noting the orientation of the slot in the worm gear and rotating it approximately 180 degrees. Since the headlights traverse an arc of less than 180 degrees, you can orient them so that only virgin teeth are active. It's a matter of being able to visualize the geometry as the gear rotates and understanding rotation direction vis-a-vis opening and closing of the headlight buckets. The worm gear is available from all the usual parts sources and are not outrageously priced, so the easiest path might be to just replace them, but keep your old ones.

As you can see, the worm gear is pot metal and the worm is steel, so when the headlight bucket hits the stop the worm will tend to bend the soft teeth of the worm gear. For this reason, it's best if the headlights rotate at the same speed and you want to release the switch as soon as the headlight hits the stop to avoid placing a high stress on the worm gear teeth.

I just reviewed the info in the '63 Shop Manual, and it's less comprehensive than I recall. I guess I figured out the headlight transmission by disassembly and inspection, which is fairly straight forward as you found. I'm mystified by this discussion of "motor speed control adjustment". If there is an adjustment at the end of the armature shaft, it's there to adjust the armature end play. If there is no end play, they could bind, and too much endplay could also cause problems. Since there is no spec, I don't know what it should be, but if they have a bit of end play, you should probably leave them alone. My best guess is that end play should be in the range of .010"-.020.". You definitely don't want the endplay to go to zero as this will cause the armature to bind, and it will draw excess current. The worm shaft,takes a lot of end thrust, especially when the headlight bucket reaches the stop and the motor stalls, so the adjustment is there to keep initial end play at a reasonable spec and adjust for wear in service.

As DC motors they probably have brushes, but since they spend so little time energized, I doubt if the brushes wear out. There are two hot leads into the motor - one from each position of the switch - plus a ground, so I assume the the motor direction is established by how the field coils are polarized based on which wire is energized. I'm not sure what purpose the points you found serve without looking at how they are wired and/or mechanically activated. They could have something to do with motor direction or they could be an internal circuit breaker. The headlight motor circuit does have an external breaker, Possibly the internal points act to cut motor current when the motor stalls and the external breaker protects against shorts. Do the points appear to be opened by armature end play? Could be the armature just bears against the adjustable thrust botton at one end gong one way and armature end play opens the points the other way to kill current to the motor when the headlight bucket stops force the armature to a position where it open the points. Again, without taking a motorr apart for inspection, I can only guess.

My suggestion is that you start a new thread and ask your questions about the motor internals. I expect there is someone out there like Bill Clupper or Jack Humphrey who has had the motors apart and can explain their internals. This thread is getting pretty far down the page and fewer are probably viewing new posts.

If you have the motor apart, check that the brushes still have some material left, but without a new one to compare it's tough to tell how much they are worn. The armature shaft should fit fairly snug in the bushings and rotate freely. Clean the bushings and put a VERY thin film of white lithium grease (NOT wheel bearing grease) on them prior to assembly.

Duke

[Craig S.]

Re: C2 1965 Headlight Motor Rebuild

Duke and George - you are right, this thread is getting long. I have taken the advanced 5 hour evening class from Steve Hack (Eastern Corvettes) on this topic, which also included the windshield wiper motor repair.

First, the points you reference are a thermal overload protector, with a bimetal strip that heats up and opens the points when the motors bind, draw too much current, and is designed to prevent thermal overload of the armature windings. This phenolic plate is held in place with two spring steel clips, and you can pull hit out over the armature end. It also contains the spring loaded carbon brushes and springs, so be careful when you remove it you don't loose parts. Its sort of like working on an alternator. These brushes NEVER wear out, and are not replaced. they see so little run time they virtually last forever. Once the brush assembley with integral points is out of the way, you can extract the armature. If it does NOT come out freely, don't pull! There is a spring loaded heim ball shaped bronze oilite bearing in the rear housing that is self aligning. It is VERY common for the armature shaft to freeze to the bearing, and then the total bearing spins in the spring clip alignment asm I mentioned. This happens frequently, and results in slow running motors with excess current draw. To get the bushing loose, and this is touchy (Steve does it all the time and has excellent luck) you need to carefully push the armature TOWARDS the thumbwheel end, and when holding it against the end bell, use a small torch to heat the housing NEAR the armature, keeping the bronze bearing in contact with the end bell with force from your other hand. Mount the hosing loosely in a vise. If you don't push the armature towards the end bell, you won't heat the bearing up, just the case, and accomplish nothing. The trick is heating enough to expand/loosen the bearing so you can carefully tap the armature loose with a small brass hammer, without overpowering and forcing the bearing through the spring steel cage. This cage, once it pops through (and it will) is a one way affair, and to repair AFTER you do that (and I know, I did) yo have to follow the three screw capture process I explained a couple weeks ago in a long post (you can search for it). Also, don't overheat the armature when you perform this operation, as the the end play is controlled by a PLASTIC section on the armature, and it WILL MELT if too hot. You can also burn up the plastic plug housing if you are not careful. So...my first crack at this did not succeed, and I ended up with the bronze ball coming out with the armature. It was very tight, and I carefully worked it loose, and used the 3 screw floatiing repair process.

As Duke says...NEVER use wheel bearing grease, only WHITE LITHIUM. This is the correct grease to use in these assemblies. In the gearcase, pay careful attention to the cupped sring washer placement etc. Steve DOES adjust the end play to control the motor timing, but you must maintain at least minimal play that you can feel when you grab the armature (as Duke mentions 10-20 thousandths is reasonable). IN spite of the thinking that you would have to bind the end play to slow, it does seem to be controllable even with some end travel. We timed a pair in the class at Bloomington, and Steve puts a small mark on the end of the pot metal gear on the end you see in the housing (end opposite engaged end) and times the rotation for say 20 seconds, counting the number of revolutions, and adjust one or the other motor so they are similar. Both still had end play when done.

Hope this helps!....Craig