My bus air wipers work pretty well, but they are exhibiting a strange behavior, and I'm wondering if it is indicative of bigger problems in the future. When I turn the offending wiper off, it moves to the center of the twin windshields, as I assume it should, then slowly decides it wants to be on the outside of the windshield.  It starts moving to the outside very slowly and then slams to the outside, staying there.  I think it may be a leaky valve or something similar.  Any ideas? Post by: Sebulba 

Post by: dtcerrato 

We also have air wipers. When you say one of your wipers is moving towards the outside, is it caused by the wind while you're running?  We use the "Park" feature on the control knob to position the air wiper in the down (parked) position otherwise what you described would happen with our wipers too. 

Post by: Sebulba 

The wind has nothing to do with it.  When parked, it behaves in the same manner.  The driver's side wiper always rests on the left side of the windshield and after some time; it returns to the middle.  The passenger-side wiper always stops and stays in the center position as it should.

I suppose I didn't think I needed to do anything but turn it off to allow them to park in the center where the two windshields meet.  I just looked at the control and see only 'On', 'Off', and 'Push to Wash'.

Post by: Iceni John 

Have you recently overhauled or disassembled the control valves or wiper motors themselves, or have you reconnected any airlines to them? If the Park function seems to be reversed (you said "it slams to the outside and stays there"), that would suggest that the airline is perhaps not where it should be. There are three airlines to each motor: Run, Park, and Exhaust. Is the control valve hissing or leaking?

When I overhauled my Sprague HP-200 wiper motor, I inadvertently reconnected its internal timing rack incorrectly, and it operated strangely until I resolved the issue.

Post by: Van 

Depending on the type of lubricant that was used, the wiper motor can be affected by any moisture in your air system. Carefully disassemble and clean the wiper motor valve.   Don’t lose the O-rings. They may need to be replaced.  My Eagle wipers had dried lithium grease in them and did exactly what is being described. 

My wiper motors were too far gone to operate correctly, so to save my sanity, we went with new electric motors and never looked back. Clean your windshields thoroughly and apply Rain-X in the meantime until you can repair or replace the wipers.  P.S. Mark your air lines and their orientation on the motors before disassembly. 

Post by: Iceni John 

One straightforward and cost-effective fix for air wipers is to add an inline oil mister lubricator to each motor's main air feed. This ensures that whenever the wipers are in use, the inside of each motor receives sufficient lubrication, keeping everything running smoothly and quietly for many years. Easy!

Additionally, it's easy to test-run the wipers every month or so to refresh the lubricant inside them.  This is part of my bus's monthly maintenance checks, which I perform when I'm not driving it for an extended period. My wipers always work well, even after many months of non-use.

I also insert a small stainless cotter pin into the hole at the base of each arm to hold the wiper blades away from the glass while the vehicle is parked. This way, the rubber blades don't get permanently bent, which causes them to chatter and smear.

Post by: lvmci 

Rome Trucks in Georgia sells new and rebuilt Sprague windshield wiper motors and kits.

Post by: plyons 

Quote from: Iceni John 

 
Hi John, your idea re: the inline oil mister is intriguing.  Could you please share how you constructed it, or where you purchased the oil mister (including the model number, etc.)?

Post by: Iceni John 

I bought two 1/4" inline lubricators from Harbor Freight some years ago, but they discontinued them a few years later.  eBay has what appears to be the same units as those I bought: https://www.ebay.com/sch/i.html?_from=R40&_nkw=air+inline+lubricator&_sacat=0   

Scroll down to the listings "1/4" Mini LUBRICATOR air in-line OILER compressed air compressor" for $18.76 or $14.99.   

They work OK, but the adjusting needle is finicky; if you unscrew it too much, it pops out of the top of the lubricator, accompanied by a mini-geyser of oil (don't ask how I know 😊).   After you've set the adjuster, it shouldn't require any further adjustment.   

I used Triflow oil, thinking that the PTFE (polytetrafluoroethylene) in it would be beneficial inside the motors. However, the PTFE quickly settled out into a white silt at the bottom of the reservoir, so the motors are now only receiving plain oil.   I installed each one inline, just a few inches from the motor, using some reinforced braided vinyl tubing, so I can see how much oil is being pumped into the motor.   Just make sure the exhaust tube won't drip oil onto anything important under the bus!   So far, so good.

Norgren and others make similar lubricators, but they cost much more than $15!   Maybe they work better, maybe not, but for our modest needs and sporadic use, I think the cheap units are just fine for a converted bus.

Post by: plyonsMC9 

Quote from: Iceni John 

Great information - my project begins, thanks very much, John!

Post by: Coach_and_Crown_Guy 

Inline air supply oil misters are a common type of industrial supply item. Used in almost every shop air system everywhere for maintaining lubrication for machines and equipment. I'm sure you can find an appropriately sized one at any local industrial supply outlet or Grainger, although you may have to pay a premium. 

Post by: epretot 

You may have read in the "maiden voyage" thread, mine over-traveled and nearly flew into the lane on my left.  I'm thinking about electric, but perhaps tuning them up is a better idea.  One of the arms broke, though.

Post by: Sebulba 

Quote from: Iceni John 

I have done nothing, and it has always behaved this way for me.  It parks the arm where it should, and then it creeps, then slams to the wrong side.  I wonder if the Park feature has a leak in it or something. Don't know enough about how it functions to diagnose.

Post by: Van

Thanks for the suggestion.  Yes, I use Rain-X.  I rarely use the wipers, but the driver’s side wiper is always on the outside and looks a little derelict. The wipers work fine, except for this idiosyncrasy.

Post by: Sebulba 

Hi Van, that makes sense; for some reason, the valves just aren't functioning properly. Not at the top of the list of things to do at this point, but maybe get an electric unit for the driver’s side when I can't stand it any longer.

Where did you get yours?  Were they an easy install?  Did it use the stock switch location?

Post by: Van

Give this a try. https://getautotex.com/