m35a3 air assist steering.

fireman5

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I have a question about the a3 air assist steering. In the tech manual it says there is a shutoff valve to turn it off. Is that just for emergencies or could it be shut off permently? I'm not a fan of the air assist steering. But I don't want to make any modifications to disable it.m
 

AceHigh

Well-known member
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Princeton WV Lake City FL
I always considered that valve usable for "limp home mode" or diagnostics. I doubt it would hurt anything to leave it closed, but I love my air assist and won't leave home without it!
 

187

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Youngstown, OH
I suppose you can shut it off. I believe there is a valve on the firewall and there is a regulator mounted on the inside of the left frame rail, close to the front of the truck. It may not be an issue for you, but the A3 wheel is smaller than an A2 wheel. Might be more difficult to turn than an A2 because of that.
 

dogfishtroop

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Pataskala, OH
I just bought 1993 m35a3. Owner drove 126 miles to me and reported no problem with steering. I drove 1/4 mile and could not turn the wheel, was able to get home and inside but can't seem to find any air leaks after opening the shutoff valve on the firewall full open. Now cannot turn wheel at all, locked up. Any suggestions where to start?

Follow-up; I found air is feeding both sides of the air assist cylinder regardless of the wheel position. Tried the mystery oil trick but did not change torque valve operation. If I understand the Air-O-Matic Bulletin operation description the end towards the front of the truck should move in and out to compress or release the valve position to direct the air to eithe rside of the air cylinder. Has anyone experienced this problem and attempted a fix?
 
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gimpyrobb

dumpsterlandingfromorbit!
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Cincy Ohio
First thing I would check is, if its getting air at all. There is a pressure protection valve that will not pass air to the system, until you have 60psi(minimum) in your tanks. Next step, take the lines off the air cyl and see if they get air from the steering link.

As always, BE EXTREMELY CAREFUL WITH COMPRESSED AIR SYSTEMS!!!!!!!!!!!!!!!!!!!!!!!!!
I would make sure there is no compressed air at all before opening any of the lines!!!!!!!!!!!!!!!!
 

URSATDX

Member
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So Jersey, NJ
The air assist system is just that. It assists.
You should still be able to drive it even if the system is not functioning properly or at all.
Turning the wheels while at a stop will be very difficult, for some impossible.
Even when the system is working fine it is just an assist. It will never be
a full power steering system as you might find in a modern road vehicle.
Search the forum and you'll find a bunch of info on repair and maintenance on the
"Air O Matic" system.
 

dogfishtroop

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Pataskala, OH
The air assist system is just that. It assists.
You should still be able to drive it even if the system is not functioning properly or at all.
Turning the wheels while at a stop will be very difficult, for some impossible.
Even when the system is working fine it is just an assist. It will never be
a full power steering system as you might find in a modern road vehicle.
Search the forum and you'll find a bunch of info on repair and maintenance on the
"Air O Matic" system.
Thanks. Discovered the torque valve was feeding air to both sides of the air cylinder essentially locking the steering effort. None of the tricks with Mystery oil helped so now need to find a torque valve. So far no luck following the threads referencing sources for a rebuilt or nos valve. According to the air-o-matic bulletin 82809 pg. 6 rebuilt torque valves are available and includes a chart with valve number and truck or bus application but air-o-matic is no longer around. Maradyne was no help nor was Power Steering Specialist both referred in threads.
 

URSATDX

Member
138
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Location
So Jersey, NJ
The torque valves are scarce and reflected in the price if you can find one.
I introduced a significant amount of air tool oil into the air side with
front of the truck on jack stands. Turning the wheels back and forth.
I started with nothing but now have something. I also oil, regularly, through
the air intake side of the valve. I have read, here, that a member was successful at
disassembling and rebuilding the valve. It appears, to me, that they are designed to
be difficult to repair. Be sure to buypass the inline regulator on the air side supply line.
I'd be tempted to remove and completely immerse the valve in air tool oil and supply air
while on the bench to see if you can restore the valve. Mine was slow to respond but
over time it got better.
Be well
 

dogfishtroop

New member
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Location
Pataskala, OH
The torque valves are scarce and reflected in the price if you can find one.
I introduced a significant amount of air tool oil into the air side with
front of the truck on jack stands. Turning the wheels back and forth.
I started with nothing but now have something. I also oil, regularly, through
the air intake side of the valve. I have read, here, that a member was successful at
disassembling and rebuilding the valve. It appears, to me, that they are designed to
be difficult to repair. Be sure to buypass the inline regulator on the air side supply line.
I'd be tempted to remove and completely immerse the valve in air tool oil and supply air
while on the bench to see if you can restore the valve. Mine was slow to respond but
over time it got better.
Be well
Thanks for the response but I gave up and ordered a hydraulic power steering conversion. Will cost twice as much as a torque valve (which I never found)
but should solve my problem, bad shoulder. I'll share my experience here with the installation.
Staying well
 

URSATDX

Member
138
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Location
So Jersey, NJ
I really want a true hydraulic system.
There are some that might be affordable but don't offer
redundancy in the event of failure.
Where did you buy your conversion from?
 

dogfishtroop

New member
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2
3
Location
Pataskala, OH
I really want a true hydraulic system.
There are some that might be affordable but don't offer
redundancy in the event of failure.
Where did you buy your conversion from?
I found "Waterloo Specialties" phone number 410-549-6649 has kits for a2s and a3s . Costs will be $2,230 +/- depending on the application. A bit pricey but for me I don't have a choice. Installation will take some work but the tools described for installation seem pretty basic. Go to waterloospecilties.com and you'll see the a2 kit parts list and pricing. Only extra to the kits are the hydraulic lines. I did a bit of research but didn't find anything to compare to for price or availability.
Good luck and post your findings if you come across another supplier.
Stay well and carry on.
 

URSATDX

Member
138
18
18
Location
So Jersey, NJ
I found "Waterloo Specialties" phone number 410-549-6649 has kits for a2s and a3s . Costs will be $2,230 +/- depending on the application. A bit pricey but for me I don't have a choice. Installation will take some work but the tools described for installation seem pretty basic. Go to waterloospecilties.com and you'll see the a2 kit parts list and pricing. Only extra to the kits are the hydraulic lines. I did a bit of research but didn't find anything to compare to for price or availability.
Good luck and post your findings if you come across another supplier.
Stay well and carry on.
I've looked at the Waterloo P/S kit. Fair price.
True power steering. Good company.
 
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cattlerepairman

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URSATDX, can you elaborate? I have the Waterloo setup on my truck and the steering box (a metric GM Saginaw 710) is just like any other steering box in that it allows steering without hydraulic support. There is still a mechanical connection between the steering shaft and the steering linkage. A true bear at standstill or slow speed, but, when rolling, I can still steer. I agree with you, were it different, it would be problematic on a public road.
 

Jbulach

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Sunman Indiana
I apologize if I conveyed improper information.
When I looked at the Waterloo set up they stated "For off road use only"
I assumed there was a lack of redundancy.
Again, I am sorry if I was wrong in my assessment.
Looks like a typical factory, on road design. Where does it say "For off road use only"?

I would guess their risk, and liability disclaimer is just to protect them from us, due to they have no control over how we actually install, what we do, or build with their parts after they ship them.
 

URSATDX

Member
138
18
18
Location
So Jersey, NJ
Looks like a typical factory, on road design. Where does it say "For off road use only"?

I would guess their risk, and liability disclaimer is just to protect them from us, due to they have no control over how we actually install, what we do, or build with their parts after they ship them.
Looks like a typical factory, on road design. Where does it say "For off road use only"?

I would guess their risk, and liability disclaimer is just to protect them from us, due to they have no control over how we actually install, what we do, or build with their parts after they ship them.
I have retracted my previous post.
Apologize for any misinformation that I may have posted.
I confused the Waterloo system with another manufacturers system.
My mistake.
 
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