MC9 Wiper Motors, trying to fix or replace, I have questions

[neoneddy]

So I bought some new wipers motors from an MC9 that was getting parted out.  Turns out they are not the same as the ones I purchased. Photos Attached is what I have  and the 3 air lines on the passenger side.

In the photo  of my lines, the white one was connected to the PARK port on the original motor.

One issue with my original  wiper was the gasket was blown on  one side.  I  made my own from RTV, that is holding fine.  I bench tested the wiper and it moved fine if I put air in each port alternating.  It didn't seem to want to move with air supplied only to the IN port.

So I tried the new motor with only 2 ports, it worked great if I connected the white line (old PARK line) but it didn't seem to  want to stop.  If I connected one of the red lines to the other port it stopped. 

I'm starting to think it might be my control knob that is messed up as no matter the position it's always blowing air out to the PARK line.

So, what do you guys know about these two motors? which one is best to keep using?   Think my control knob is hosed?

Also good news, I think this was a major source of my slow air leak after shutting down Bad news, I don't think my check valves are working right, because with the wiper motor disconnected the air pressure drops all the way to 0 pretty quick after shutting down.

[buswarrior]

You are working in an unknown condition, you don't know whether anything is working correctly.

Pull the controls out of the coach, make all of it work on the bench.

If you are in this far, you'll want to freshen up ALL the lines between controls and motors anyway.

Control should have to twist against a spring for "park" and then spring back to "off"

There are delay controls available for the air wipers on the D models, really a nice upgrade, if you want to spend ca$h on wiper controls, spend a bit more for better functionality.

The rest of the coach has to be evaluated before deciding the protection valve is shot, don't make trouble before its time.

Happy coaching!
Buswarrior

[neoneddy]

Leaving for a trip out west here Thursday, I guess I'll have to roll with my Driver's side wiper f we hit wet weather or wait it out.

When we get back I'll pull it all apart.

[neoneddy]

Update: I took the unit on the bench, lubed up the internals real good and when I reset it to the start position and get it air in the IN port it worked normally , so at worst it's the control knob.   It works far better than the driver's side now, I should do that one now.

[chessie4905]

Went through these issues when I rebuilt mine. One had a larger bore than other one. O rings weren't sealing in bore. I thought the thing was leaking around valve body. Finally discovered oversize bore that piston rides in. Took one out of parts bus and swapped parts to fix it. Only didn't have enough grease in unit now. Tried to get just grease from Luke without rebuild kit. He didn't have it. Got the part number off the grease packet and ordered from Mohawk. A few days later, got a phone message from them. They need to order the grease from Sprague and minimum order is 10 packs. I need to call back and see how much 10 pckets of grease will cost. I only need one and a spare or two.

[lostagain]

I don't think the special grease from Sprague is necessary. If I remember, when I rebuilt mine a few years ago, I used grease made for boats, or just white grease, whatever I had on hand. Works fine still.

JC

[chessie4905]

Thats my thinking. White Lubriplate or a mix of synthetic trans fluid with synthetic grease should work as well. The main idea is it be something like sour creme in consistancy, but not change in stiffness over wide temperature range and stay in place. There was talk over on trucker forums about different combinations with satisfactory results.

[GnarlyBus]

Wow, a wiper thread without anybody chiming in about how much they love their ELECTRIC wipers?! 

Thanks for the pics. It looks like you replaced your original wiper motors with the HP 200 model which is a little different but much more common and available. Good to know those can be made to work. I was wondering about that...

[neoneddy]

Actually I'm trying to get my original one to work again.  It was one of those things where, my original one was less hosed up than I thought.

Eventually I think I'll switch, just not now.  I'm sure electric ones are great, but that very not right now.

[chessie4905]

Ordered the ten containers of grease from Mohawk.A little less than 6 bucks each. Enough for one motor or you might squeeze it out for two. If anyone needs some, email me.