PD 4106

[Busidiot!]

hi, This is my first time posting on this forum and we are new bus owners that have no clue where to begin. My husband has literally torn our 4106 apart and was trying to replace parts and found more problems. The problem at hand at this moment is the windshield wiper control valves. He bought a new control valve for the right side, but it doesn't work. The left side is now leaking air. Any suggestions  or help would be greatly appreciated. We are very frustrated at this point. We see beautiful buses everywhere and are wondering who does this work. we have spent countless hours researching the internet with little to no results. My husband has done much work on it already but we have yet to use it, Please help.

[eagle19952]

air wipers that are 40-50 years old are not often revived.

even if they are, you'll still wish for electric.

No time like now.

[Busidiot!]

Thanks, where do we start?

[richard5933]

Where to start for wipers on a 4106? My suggestion would be to call Luke at US Coach tomorrow and see what he has available. Could be that he has direct replacement parts to convert to electric, or could be that he has the parts you need to make the air wipers wipe again.

I had air wipers on my 4106 and found that they did an okay job. Drove our 4108 home to Wisconsin from NJ through lots of rain. Air wipers did their job. That said, I can definitely see the advantage to upgrading to electric. It all depends on how much convenience you are willing to sacrifice in exchange for period accuracy and whatever 'cool factor' comes from keeping the air wipers.

What ever you decide to do, I have always found advantage to having an idea of parts availability BEFORE tearing things apart too far. This helps to guide me and certainly lets me know what parts I have to guard against further damage.

There are also a few YouTube videos about air wipers on the GM buses.

[TomC]

There are many companies that make direct replacement electric for the troublesome air wipers. I replaced mine in my AMGeneral transit. Has a separate electric motor on each side, but with the electronic controller, they stay in synch. Now I have variable adjusted interval, low and high speed. Plus they have the windshield washer built into the wiper arm. A bit of a challenge to make them work, but oh is it worth it.
As far as finding someone to do the work-most of us do all the work ourselves-that's how you save money. The only jobs I did not do on my bus conversion was the engine and transmission overhaul, air bag replacement, upgrading the air steering to Sheppard hydraulic, had the insulation blown in (very messy job) and painting the outside. Otherwise I did the tear down, screwing 1x2 into the walls for anchoring the plywood walls, building all the cabinets, doing all electrical and plumbing, installing the generator, installing the deep cycle batteries, etc. This is why most of us buy buses-to build them our way and to our way of thinking. Good Luck, TomC

[Busidiot!]

Where did you get yours from?

[Geoff]

I was able to get an left air wiper motor rebuilt for my 1982 GMC RTS bus through the local truck parts dealer.  The right side was okay.   Try to find a FleetPride store near you.

[Templar52]

dismantle your wiper motor. Don't be afraid. There is not many parts on thoses motor. You will be able to see your problem easely. Sometime,there is to mutch oil in the cylinder and that oil goes on the tiny air passages controlling the wiper.

[Melbo]

Also your location in your signature line is helpful in case someone is near and can offer help

Melbo

[Iceni John]

If you have Sprague air wiper motors and valves (a common brand), parts are available from Rome Truck Parts in GA.   I rebuilt my driver-side Sprague HP-200 motor a year or so ago because it was leaking internally  -  just remember to mark the position of the sliding cam relative to the gear that rotates the shaft, otherwise it won't work right when you reassemble it!   It just needed a few dollars'-worth of O-rings, plus an hour or two of cleaning, and it now works perfectly.   One thing I did that will help for the future was to put an inline mister lubricator in each motor's air supply:  they're always lubricated now while they work.

The only thing I gave up on and replaced entirely was the air-operated washer pump that dribbled fluid back onto my foot every time I used it.   I now instead have a pair of electric washer pumps from Pep Boys, cheap and effective.   I can't imagine the Sprague wiper control valves are too complicated  -  maybe a few O-rings will also fix them?

If the wipers are working hard to push heavy wet snow off the windshield, air motors won't overheat under a heavy load unlike electric motors that may overheat and burn out.   There's still something to be said for the relative simplicity and repairability of air wipers.

John  

[buswarrior]

As air wipers get worn and tired, they won't start by themselves, often depending on where they are stopped on their sweep.

For some sense that the world has not ended, turn on the air control, and go outside and give the wiper arm a push, see if it will start operating with some help.

See if they will start from a slightly different resting place?

You need some sort of win here, get that bus out on the road and drive it, somewhere, anywhere.

The busnut hobby destroys finances, people and relationships...

happy coaching!
buswarrior

[eagle19952]

8 people have posted that their wipers were ...in need of attention...
that ought to be reason enough to change them.

[dtcerrato]

We're still running air wipers on our 53 4104, & they work well. Some have cintered brass filters that clog up tight & restrict air - worth while checking as it may not be a faulty wiper. Nothing wrong with air unless they're at the end of their service. Dive in & find out.

[RJ]

Welcome Aboard!

Sorry you're having problems with the wipers on your 4106, they're actually incredibly reliable when serviced and/or repaired properly.

As mentioned above, Luke at US Coach in NJ is your BEST source of parts and info on this "Sports Car of Buses" that you now own.  He can be reached Mon > Thurs at 1-888-262-2434.  Luke's probably forgotten more about GM buses than all the combined knowledge on these boards.  Strong supporter of this crazy hobby - support those who support us!

What is the VIN on your coach? PD4106-XXXX?  There's a fellow in CA, Jon Ulse, who's been tracking all surviving GM coaches for historical purposes.  Post yours here, and I'll forward the info to him.

FYI, there's a Facebook page dedicated to 4106 owners, if you're interested. Simply search for GM PD-4106 Bus using FB's search box.

Also, there are three books that you should have in your "bus library" - The Operator's Handbook, the Maintenance Manual, the Maintenance Manual Supplement, and, of course, the Parts book.  Optional would be the shop manual for the engine and the transmission, too.  If you don't have them, they are available, both in print (harder to find) and electronically (ask on the FB page.)

Finally, please take a couple of minutes to edit your Forum Profile to something similar to mine (and others) below.  At least first name(s), home base city/state, and make/model coach plus it's powertrain.  This will help us help you even better, plus you might just find out there's another busnut living nearby!  Simply click on the "Profile" tab above, and when the next page pops up, scroll down to the "Forum Profile" option, click on that and follow the instructions.  Thanks in advance, and again, welcome aboard!

FWIW & HTH. . .

[chessie4905]

Electric wiper conversion kits are listed forMCI and Eagles. They are pretty expensive. Unfortunately, none are available for GMC's. Since thousands have been used and no transit companies have been known to convert to electric on their coaches of past years, they couldn't  be that bad. Just like many old systems, they need cleaned, rebuilt or replaced. Clean air supply filter, rebuild or replace controls and take care of motors. They will work like new again. Electric wipers are definitely nice to have, but until someone offers a quality plug and play setup for GM's, I'm not interested in chasing down suitable electric motor candidates and spending the time to adapt them to work on my coach, which will require a significant trial and error time to get them to mount are provide the range as current ones. The addition of lubricators will help a lot, make sure exhaust line from motor goes outside of body to avoid breathing mist.
  If someone is intent to do a GMC, I recall the flat nose Blue Bird busses had electric pantograph wipers and would go for them first as candidates. Blue Bird tended to use better quality components than other competing body companies back then.