Vacuum windshield wipers

[Dani]

My wipers work fine (50 buick series 40), but it seems that when the motor is under load such as driving up a hill-that the wipers will slow down severly and sometimes even stop until there is less load. Is this a sign of a vacuum leak? I thought about my vacuum pump being bad but then the wipers wouldn't work at all right? I can sit and rev the engine the wipers will work faster with higher rpms, its just when it is under load it does slows down/stops. Thanks guys

[imported_NikeAjax]

There's nothing you can do about it! I got an electric motor for mine, and now I don't have to change my pants when it rains: "OH s**t, I can't see!" I got mine from Buick World.
Jaybird

The situation you describe, and the function of the wipers, is known as:

"Absolutely Normal!"

[imported_NikeAjax]

One thing you can do to help is get yourself a reservoir and a check-valve so you don't lose anymore vacuum. Some of the mid-60?s cars have them; the one I have on my Rambler is from a 1965 Chrysler Imperial. Or you can use a juice-can with a tube sticking out either end, but make sure you have the tubes sealed up VERY well; make sure it?s steel. The twelve inches of vacuum developed from your pump, will not collapse one of these, I?ve seen them hold at 21-inches, and still very sound.
Jaybird

[imported_MrEarl]

Normal yes, very. safe?...not very I don't guess. If it's a daily driver, Jaybird's dead on.Personally with my Saturday night and Sunday cruisers, I'll stay with the old slow vacuum wipers that MADE one slow down when it rains like they should in the first place, and the dimming lights at stop lights caused by the old Delco generator, the swaying ride from the Firestone bias tires, the press accelerator to start and the baseball games and gospel music that is always there on that old Sonomatic and ...............


(anybody else care to add anything)

Actually, you'd be surprised how well they can work after a wiper motor rebuild WiperMan.com and making sure the vacuum pump is operating at full capacity and that all the lines leading to the motor are tight and there is no air loss to the washer unit.

[Dave@Moon]

Two words: Rain-Ex! The stuff is great, especially at drive-in movies.

My Falcon had some of the weakest wipers ever. They'd come to a dead stop at times even when the whole system was in perfect order. However, if I just lifted my foot briefly (a good head of steam was needed out of the 144 cu. in six when going up hill to do this) the wipers would literally fly. On deceleration they'd be doing 2 or 3 cycles/sec. at top speed, so it wouldn't take long to clear the windshield. I'd think most good working systems (especially with a vacuum booster) should be able to repeat that rate.

A vacuum reservoir will help with brief accelerations (on-ramps, etc.), but sustained up-hill rides will still be a problem.

[Gene Brink]

Amen to Dave's post about Rain-X. Use it, keep a good coating of it on your windshield, and you will be amazed that you can drive without the wipers on at all because the water sheds so well. Don't know how it does what it does but it does it really well! (Bought some Rain-X wax a few weeks ago in the hope it would do something similar to paint. Does not but a decent wax.)

One other point I would raise is to be certain your motor is not part of the problem. They need to be properly greased to function smoothly and with minimal drag. Easy to open, clean and lubricate if needed (but be careful you don't want to break anything).

[imported_buick5563]

I just spent a whopping two hours yesterday rebuilding my wiper motor. It didn't have the power to even remotely move. I pulled it, cleaned it, lubed it (plumbers silicone grease), made a gasket(from a manilla envelope), siliconed the snot out of the gasket surfaces (including the brass bearings top and bottom which is where I think my leak was), installed it and it moved across a dry windshield for the first time in the 20 years that I have owned the car. The only difficulty was after a few Shiner Bock beers I put the two halves of the gasket that I had facing different directions (one up one down) My bad. If your car isn't a daily driver, you might try to miss the rain, keep rain-x handy per the upper posts. If it is your daily driver, you should know the car well enough to slow down when the rain starts.KEEP YOUR DISTANCE! Even though it doesn't rain that often here in Austin, when it rains it pours. My bias ply tires cause me much more grief in the rain than my wipers. Try rebuilding it, it's just not that hard.

[Mrbuick714]

Installing a new fuel pump fixed my slow wipers

[Dani]

My vacuum/fuel pump is in good shape so I will just open up the wiper unit and lube things up, as well as install a vac can (luckly I have a spare from one of my 1966 Thunderbirds). Aside from these things, I will just have to get used to these wipers, doesn't look like I can completly stop them from slowing down. Thanks for all the ideas guys.

[dunbar53]

Mr. Earl is correct. When these cars were new, the wipers operated satisfactorily. If the system is in good repair, there is no reason you should have to endure slow wipers under load. The most common causes (all stated in the thread) are the vacuum chamber of the fuel pump, a leaky vacuum line, or a bad diaphragm in the wiper motor. I always go for the fuel pump first. People love to customize nice original cars, simply as an expedient solution. Installing electric wipers circumvents the problem. Wish you luck.

Bernie