The Stovebolt Site Forums The Shop Area General Truck Talk please help

I don't know where to post this question ( just joined today) but here goes anyway. Does anyone know about vacuum wiper motors? Mine works in one direction but not the other.What makes the thing operate in both directions? I don't want to tear the thing up just to fugure the thing out. Thanks...

I only know that the set I had got slower the faster I would go! I would slam on the drum brakes ( which barely worked when wet!) in order to raise the vacuum enough to sorta see all the immovable objects I almost hit! For my mony I'd convert to electric post haste ( and I live in sunny socal!)

Send it here. It will work better than new,
Scott

I don't know how slamming on the drum brakes raises the vacuum. Letting off the accelerator does allow the vacuum to build.

The vacuum motor has a set of valves that control the direction of the vacuum derived force. There is a problem with the wiper motor.

So why does his wiper work in just one direction?

come to think of it, I was probably more panicky from not seeing, but if it stayed in gear it would increase vacuum in concert with closing the throttle!

When the vacuum is applied, it is applied on one side of a moving paddle. The force from the pressure difference moves the paddle all the way to one side and that triggers a sequence of valves that causes the vacuum to be presented on the other side of the paddle. This causes the paddle to move in the opposite direction. If either of the valves fail to operate, the reciprocating action will stop.

Thanks for the input. Sounds like I've got a valve problem to fix. Does anyone know where to buy a rebuild kit for this thing?And where I can get one of those special oblong tools to open it up with?

See my first post,
Scott

There are no rebuild kits available. They were all bought up years ago by a few individuals who now rebuild them. Take yours off and look it over, they are pretty easy to work on. Sometimes just a good cleaning is all they take. If it needs more then that, send it off to the Wiper man, he does good work. Joe

Here's an oldtimer's trick. There is an open hose port on the wiper motor, where the air gets sucked in to operate the swinging paddle inside the motor. Attach a piece of vacuum hose to this port, and submerge it into a can of lightweight tuneup oil like Casite or Wynn's Friction Proofing, etc. Even Diesel fuel will work if that's all you have available. As the vacuum sucks the fluid through the wiper motor, it will clean up all the gunk inside and just burn it along with the fuel mixture from the intake manifold. The engine will smoke a little for a few minutes, but no harm done, as the additive will help dislodge any carbon on the intake valve stems on the way by. BTW, this also works on the vacuum-assisted shifters on late-40's Chevy cars.

Jerry

If you want to try lubricating the wiper motor, here is what Bob Adler suggested in an article a few years ago (in This Old Truck maybe).

I took mine apart and cleaned everything. I sealed it back up with silicone. It seems like I used teflon plumbers tape, the kind you use to seal the threads on pipes, to seal the area that the paddle pivots from. I lubed the sealing surface of the paddle with a little silicone grease. I am sure this shouldn't work but my wipers move just fine. They couldn't swing far enough to make the valve change direction because the crud in the paddle chamber was limiting the travel. If you kill it send it off for repair. I used a small wrench on the screws. I do plan to replace it at some time with an electric motor. Even new the vacuum wipers were crap.

Thanks for the information. I'm going to pull mine and lube it.