how to rebuild m934a2 air windshield wiper - 939 series

Has anyone ever rebuilt the air windshield wipers on these 5 tons?

My passenger wiper is leaking air out of the exhaust port, continuously. It drains the primary tank in about 15 minutes once I turn the truck off. I opened up the wiper motor in question, (took the top piece off where the air hoses are connected), and didn't see anything wrong. It was lubricated fine. Nothing looks broken. I opened the drivers side just to see if there were any differences. Everything looks the same. I put both back together and the passenger wiper is still leaking out the exhaust port. The cover for the exhaust port is missing. That is the only thing I can see wrong. I think that is only a muffler of sorts. Anyway, anyone have experience with these wiper motors and could give me some advice?

I would buy some electric wipers, but I'm going on vacation in a week and need them to work now.

Oh, they both work, the passenger one just leaks if there is any air pressure in the primary air system.

Thanks.

The original are civy parts. Haldex formerly midland offers them rebuilt. Napa or truck pro should be able to order.

When I get back, NAPA will be able to get what I need. They can't get anything here by the time I leave for vacation.

Anyone at all ever pulled one of these apart and got it working again?

1: i've successfully done the old metal ones but only in the sense of a decent clean & lube was all they needed

2: i've have several plastic ones doing same as yours but sometimes a clean & lube doesn't do the job and that's as far as i go, don't have time to fuss with them more than that .. If a sticky one is on the driver side i just swap for a good one .. If a sticky one is on passenger side i just plug the hose and call it a day

msgjd said:

1: i've successfully done the old metal ones but only in the sense of a decent clean & lube was all they needed

2: i've have several plastic ones doing same as yours but sometimes a clean & lube doesn't do the job and that's as far as i go, don't have time to fuss with them more than that .. If a sticky one is on the driver side i just swap for a good one .. If a sticky one is on passenger side i just plug the hose and call it a day

Click to expand...

Yep, that is my solution for now. Leave the working one on the driver side and plug the other one. Sucks, I hate doing that for an extended drive but hopefully it wont rain and all will be good.

When I get back, I am going to swap to electric. That has always been the plan but those little things you forget, come back and bite you later. LOL.

Anyone have a direct replacement part number for an electric swap? I can look it up when I get back but having it already helps. Thanks for the help guys. I should have just fixed it when I thought about it rather than last minute.

Gunny65 said:

Yep, that is my solution for now. Leave the working one on the driver side and plug the other one. Sucks, I hate doing that for an extended drive but hopefully it wont rain and all will be good.

Click to expand...

hopefully ! ..

having a sticky wiper cylinder can create another issue i had once, and it may have happened to others

During a convoy move we ran into a sudden heavy thunderstorm.. I turned the wiper valve, the passenger side ran fine but the driver side limped slowly to one side, stopped, and hissed.. I turned it a little more, nothing but louder hiss.. I shut it off and worked it manually for a couple miles but difficult to do when uphill/downhill with lots of shifting to do.. Could barely see the 5T ahead of me and getting soaked from the water getting past the window seals and top of door window. To boot it wasn't even my truck , someone else "stole" mine

I had enough of that sh** show and got mad. Turned the wiper valve again and it did the same thing, went to one side and hissed.. So I turned it all the way open and left it hissing.. It stayed that way for a minute and then all of a sudden the stuck wiper took off like a metronome on speed and flung the blade right off the arm.. Gone!