Dover Composite Top Floor(ONLY) Leveling Issue.

Hello All,
I have a bank of 3 Dover Composite Elevators. All are 6 stops . One of the elevators comes normally to the 6th floor. The doors open and the elevator slowly rises anywhere from 1-5 inches and then slowly levels back down to floor level. This happens intermittently, every 3 weeks or so and only at the top floor. The car has no issues at any other floors only the top floor. The brake pads needed replacement, spring tension is good, but the problem still exists. Could it be a 6th floor bar/contacts issue? I see no indication that the car is pulling thru the brake. Why is this leveling issue only happening at the 6th(Top) floor? I know there's the counterweight to consider. What am I missing? Thanks for the help.

Check and make sure 14 and 15 contactors are working and the contacts are good.

Check counterweight runby

I am thinking that you have no comp chains and the weight of the ropes are having you come into the floor a little hot. This is not a fix, but it will let you know if that is the issue. See if it does the same thing with a few passengers in the car, or some added weight. I suspect that the Generator has brushes that are different than the ones the car was set up with. you may need to add a little series field. Or you may have a weak rectifier that feeds the motor field.

Does this only happen empty car? If so, It’s probably happening on the other floors also. I’ve had this before. Check CFC field circuit.

Spring tension isn't the only thing worth looking at. With the car only doing this at the top floor, I would think the weight of the ropes might be giving it a little extra. I know you said no indication that it's pulling through the brake, but intermittently is hard to tell. The gap between the brake coil plunger and the stop should be about a 1/4" or so. I always use a 7/16" -9/16" wrench (flat open end) to set the air gap. What can happen is the plunger isn't hitting the "sweet spot" of the coil and not getting enough pick. A lot of folks will solve this by moving the tap on the resistor, but those are solid brakes if mechanically set up right. How's the brass sleeve and whatnot? clean and free?

Also, sounds dumb, but check your spring tension under the car for the selector. Should be about 18-21" if you didnt know that already. This can cause a ton of weird issues that normally get adjusted around instead of fixed.

And.....It's always a good idea to clean and make sure contacts are hitting your floor bars like you were thinking too.

Make sure CFC relay drops out as it should. I once had some gunk on the back of the armature of the relay cause CFC to occasionally stick, causing residual to build and pull through the brake. MG sets are strange animals.