The Stovebolt Site Forums The Shop Area General Truck Talk vacuum wiper motors HELP!!

Ok guys and gals......
Two trucks and four wiper motors... and it seems that none of the wiper motors seem to want to work correctly....... When I started none of them would work at all.... So after opening them up..and cleaning out all the hard caked grease grunge..and re-lubing the paddle leather... so it's now all soft and supple.... and re-assembling the motors.... I hook them up to the vacuum line off the manifold.... and turn them on, ther work very well.... cycling back and forth....... BUT after re-installing thhem into the truck..and hooking up the wipers....... I again turn the motor on...and the wipers swipe one direction and stop.... I can get them to cycle back only with help.........

It's almost like they want to go a little bit further before cycling back ... What gives?
I've worked on lots of vacuum wiper systems over the years...and never had this problem before..... so I come to the polulace of the bolt..... for their collective wisdom.....

Michael

I've just finished rebuilding a couple of the motors
and since changing to Lubriplate Assembly grease, I've
eliminated all the slow problems...Remember when u lube the paddle you also need to lube the tub in rides in..

Also with the Lubriplate it only takes a little over an inch of vacuum to run the wipers, which translates to always working when needed...

Geoff
49 Chev 4400
52 GMC 350
55 Chev 3800
52? JD420C w/JD90 Loader
37 D4 Cat

There is a lot of friction between dry wiper blades and dry glass. Try squirting the windshield with a garden hose when you test run the wipers.

Michael,

I go with cletis on this one.

It sounds like you have correctly serviced the units, and if the vacuum lines are in good shape and are not cracked and leaking, and you have checked the wipers for good operation by manually moving them throughout their range, then its time to wet the windshield.

Let us know what happens,

As I understand it, you say the motor runs fine out of the truck, but when installed it slows to a stop.

I agree with Cletis's recommendation to reduce the friction between the blades and the glass. Don't forget to reduce the friction within the linkage, too. As I recall, mine is a rather low tech assembly having only bushings, no bearings, at the joints. Make sure you've reduced friction between the motor and the blades by lubricating those joints.

The only thing left is the vacuum level and your motor. Is it possible to have vacuum restricted through the knob? You have good vacuum on the engine side but maybe crud can build up in that little valve and starve the motor.

Just a thought.

Bill

I kinda had the same problem. I got some WD40 and spray cleaned all the linkages under the dash.Then I used a lubricating spray. This solved the one way and stop problem for mine.Oh ya I removed the radio and the speaker grill to make the job easier.It was worth doing.

Well I ran the wipers last night in the rain....and the problem still exists.. so wet windshield didn't fix the prob...and other thoughts?
Michael

Just a thought. could it be the springs are to tight and holding the wipers down on the windshield(if it is the same set up as my 42)

I had a similar problem with my 48 (I switched to electric ) they were hesitant to return ..examining the linkage and the bushing/gromet ,a pressed fiber sort of thing,it was wore out ..only way I could think to fix it without duct tape ...took an old credit card and made 2 little pieces, kinda like a bread tie , sprayed them with silicone ,put them on
in opposite directions and solved my problem ...thats been 8 years ago ...take out the radio and grille ...good luck

Graflexmaster, you also mentioned that the wipers seem to want to go a little farther but couldn't. Take the windshield wipers OFF and see if things work alright without them on. I'm not sure about your particular linkage but could one of the arms be turned upside down causing a difference in length? Just trying to help.

How good are the vacuum levels of the engine? A worn engine creates less vacuum.

Achipmunk has a good point too.

Hey builder....
Well I was also wondering about the vacuum level, and hung a guage on the line last night... The vacuum reading off the wiper port on the manifold is 16in and rock steady at idle..... Which also tells me the engine is in excellent shape..smile
Not bad for an old babbit-pounder 235......

michael

Another thing you might want to look at is whether you have the right arms and blades on the truck. A lot of times the arms and blades where switched to a more modern setup. The original vacuum arms and blades are very light and not a lot of spring pressure. The blades are connected to a single kinda swivel joint in the middle and flop back and forth. Look in a vender catalog for the correct year and you may find a different type of arm and blade then you have on your truck.