Truck won't turn left

[joed2323]

Kw t800

These newer trucks, 2 2015 trucks, have gona through pwr steering pumps, filters, fluid, hoses, you name it we chased the problems. This has been a on going battle when it gets hot out. Last summer and this summer. Gearboxes I believe as well.

It is not in the kingpins, and any other steering component since we cant duplicate the issue and find a bound up steering component.


It seems like it only does this to the drivers only on their last load, so I know the fluid is warm at this point. As the drivers states when they are driving down the road and then they begin to try and make the turn it instantly feels like their is no power steering at all, sometimes they have to completely stop because they can't make the turn, usually they have to turn the opposite direction to make it un bound up.

These two trucks are the only trucks giving us this problem, and again, the power steering pump has been changed more then once.

Lot of times I cant duplicate the problem in the shop. Has anyone ever heard of such a weird issue? I mean normally when you lose power steering you loose it for good, and normally its something simple like a restricted filter or a bad pump, etc but this issue is sporadic and its driving me nuts.

Going back over the times the drivers complained, it's always when its hot, 90s, and or the drivers 3rd-4th, last load of the day. They unload, then normally drive back to the shop and the truck is fine, but this can be dangerous.

If anyone has some suggestions for me to try, im all ears

[Waterloo]

Have you thought of putting a restrictor block in to keep the power steering from going into full lock? Could these guys be stressing the PS system when they are backing and or leaving the dock?

[Wiseman]

You won't be able to duplicate the problem in the shop . This thing happens only when the power steering fluid get overheated. Ones cool down little bit everything goes back to normal . The only solution I know of is installing an suitable cooler on the return line .
I guess it all comes to component tolerance in the steering box distributor and having hard time functioning when oil gets overheated slightly above so called normal operating temperatures.

[Waterloo]

(07-20-2016 )Wiseman Wrote:  You won't be able to duplicate the problem in the shop . This thing happens only when the power steering fluid get overheated. Ones cool down little bit everything goes back to normal . The only solution I know of is installing an suitable cooler on the return line .

If it is only happening with two drivers (my bad, two trucks!)... But, I bet they are cranking the steering wheel into a full lock and holding it, in turn over heating the pump. The crap I see out here in Detroit in these tight docks would blow your mind. These guys do not know how to back, much less do it correctly, and most are in day cabs. I could tell you stories!

Has it only happened leaving certain facilities? Someplace that is a bitch to get in and out of? We still hit places designed for 40' 96" wide trailers, backing into buildings no less with little room to maneuver... Some guys beat the shi#t out of the PS and Transmission backing in, especially when heavy.

[joed2323]

Let me add some more. Thanks guys.


It has happened to numerous drivers in these two newer trucks. Our 2012-2013 trucks do not have this issue.

Their is no docks, just oil wells and unloading stations.

Normally from what I gathered it happens generally when they are driving straight for awhile. 65mph
But it has done this on occasion pulling out of a well location.

But mainly it gets locked only when trying to turn one direction.

These are double bottoms. My company has a no back up policy, these guys are not backing up lol. Especially in double bottoms.

It only happens when driving straight and trying to make left turns

Not slight left turns. Turning the wheel a few revolutions

[Rawze]

Something is obviously causing the fluid to overheat. Alignment can do this if there is no PS unit cooler. A slight pull all the time under heavy axle loads can slowly heat the oil to excess temps. As well, are you running ATF in them? that is what TRW recommended as the best oil to use I went through re-build training on them.

Solving your problem will require you to investigate why the oil is overheating going down the road. That is not normal. Any time you have an internal leak,.. or there is a constant strain/slight pull on the unit, it will simply get hotter and hotter unless there is a cooler installed.

Is it even running in its base detent position going down the road? -- or did someone jack your alignment and you just can't feel it in the steering? -- I have seen some pretty bad alignment that does crap like that and the truck not even pull to one side. To check the base detent position,.. jack the front end up on both sides so that the steering wheel can turn freely and crank up the truck. See where it "wants" to sit (the PS units center-point instead of the steering wheel center -point) and compare that to where it sits going down the road.

If there is no internal leaks causing excess heat, and it is simply a matter of your demand being too much for a non-cooled unit,.. simply install a cooler on them and call it a day.

[Hedley]

suction hose may be collapsing under pressure.... the steering shaft from the firewall to the steering box may be binding as well.

[joed2323]

Nobody has messed with the alignment of these trucks

Where should I get a power steering cooler at for these trucks

Yes I run only approved dexron atf in all these trucks.

How could the steering shaft be binding?

[Nilao]

If it was an issue turning right I'd tell you to quit hiring race car drivers.