72 wipers get out of sync

I have a 72 that the wipers work fine with one exception, after turning them on and they run for a few minutes, they get out of sync and start hitting each other on the down stroke. When I first turn them on they work fine and don't hit each other on the down stroke. The problem seems to get worse if I put them on fast speed. Does anyone know what might be the problem with them. I replaced the motor and gear about a year ago. I don't normally drive in the rain, but it makes me feel better just knowing they are there if I need them. Thanks, Jimmie

I had a similar problem with mine on my 75. I think it has to do with the wipers not sliding freely on the windshield. Someone suggested to me that I get some rain-x and it did help some, but not all.

I try to use the car on non-rainy days, and when needed I will turn them on and off every so often. It's a pain but it keeps them from jamming together when they get out of sync.
Glenn

I have the same problem on my 76. The wipers "chatter" across the window and they sometimes hit on the way down and get stuck. I've already ruined a number of blades getting bent from this. I had the linkage adjusted and I've used Rain-X. For some reason, the blades run very smoothly on a dry window - but when it's wet, it's a mess. I'm still battling with mine so not much help here, but there's "comfort in numbers"?

I'm eager to hear if someone has the solution to this problem. I too try to avoid driving in the rain, but sometimes you get caught in an unexpected rain-shower and having wipers really helps!

Note: The Rain-X works really well provided you're doing highway driving. Not so much in the city stop/go. Seems like you need to be moving pretty quickly to have the water sheet off.