REEL ADDICTION Posted November 17, 2012 Share Posted November 17, 2012 I have a 2012 and 2013 mack granite triaxle dump truck with 385 tires on the steer axle I noticed the other day while making a u turn with a load of stone I could not turn the steering wheel unless the truck was moving it was like it had no power steering I checked the oil levels and they were fine I have older granites with same size tires and it is not an issue was wondering if anyone has any idea why Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/ Share on other sites More sharing options...
mike69mackman Posted December 6, 2012 Share Posted December 6, 2012 Sounds to me the pump took a nosedive. You can check circulation of the pump and it may be fine but that doesn't mean it's building enough pressure. The other thing to look for and check is the check valve for the system see if its sticking open . Mike Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-149689 Share on other sites More sharing options...
slpwlker Posted December 7, 2012 Share Posted December 7, 2012 You got 2 steer boxes or 1? Before I dueled out my truck with 425's on it was a pita sometimes even moving. now with both boxes I still have problems but not as many but it is slower turning. Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-149802 Share on other sites More sharing options...
ramairiii Posted January 13, 2013 Share Posted January 13, 2013 I have a 2005 CV713 Granite tri-axle and mine started doing the same thing as yours. I have 425's on mine. A loader in our rock yard backed into my truck and damaged a lot of front end stuff including the steering pump which is bolted to the right front side of the motor.After fixing the truck (including a new steering pump) the problem completely went away. I would try changing the pump out. They are'nt real expensive. Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-157157 Share on other sites More sharing options...
REEL ADDICTION Posted January 13, 2013 Author Share Posted January 13, 2013 I have a single pump the truck is going to the dealer this week for some other little things and i will see what they say. I have 385s on my steer axle Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-157158 Share on other sites More sharing options...
Challenger Posted January 14, 2013 Share Posted January 14, 2013 Its probably the power steering pump. Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-157191 Share on other sites More sharing options...
Mvnfast728 Posted April 25, 2019 Share Posted April 25, 2019 On 1/13/2013 at 6:40 PM, REEL ADDICTION said: I have a single pump the truck is going to the dealer this week for some other little things and i will see what they say. I have 385s on my steer axle Still at the dealer I guess? Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-421372 Share on other sites More sharing options...
j hancock Posted April 26, 2019 Share Posted April 26, 2019 18 hours ago, Mvnfast728 said: Still at the dealer I guess? A little snarky for your first ever post. Much more productive to ask if there is a follow up to the situation because you might be having a similar problem. 1 1 Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-421422 Share on other sites More sharing options...
Sdecker85 Posted June 10, 2019 Share Posted June 10, 2019 I have a 2000w kenworth t800 same issue steers fine with front end jacked up but steers real hard (not at all) unless it’s moving king pins seem good reservoir has fluid changed reservoir filter ( was nasty) still steers hard when not jacked up does this also sound like the steering pump? Reel addiction how did you make out at the dealership? Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-424940 Share on other sites More sharing options...
Dirtymilkman Posted June 10, 2019 Share Posted June 10, 2019 Always check your u-joints and bearings on your steering shaft. I've replaced many where you couldn't even turn the steering wheel and it was just a $6 bearing. Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-424942 Share on other sites More sharing options...
Sdecker85 Posted June 10, 2019 Share Posted June 10, 2019 Steering shaft seems fine no play everything seems tight. Truck steers great when jacked up but steers hard unless moving empty it steers real hard when loaded. Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-424945 Share on other sites More sharing options...
Rob Posted June 10, 2019 Share Posted June 10, 2019 Could be a steering pump, or seals on the internal spool valve of the steering gear. Easy enough to plumb in a pressure gauge and relief valve setup to test the components. Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-424947 Share on other sites More sharing options...
Sdecker85 Posted June 10, 2019 Share Posted June 10, 2019 16 minutes ago, Rob said: Could be a steering pump, or seals on the internal spool valve of the steering gear. Easy enough to plumb in a pressure gauge and relief valve setup to test the components. Plumb in pressure gauge on outlet hose of pump? What is normal pressure any idea? It’s just weird it will steer perfect when tires are off the ground . Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-424948 Share on other sites More sharing options...
Rob Posted June 10, 2019 Share Posted June 10, 2019 1 minute ago, Sdecker85 said: Plumb in pressure gauge on outlet hose of pump? What is normal pressure any idea? It’s just weird it will steer perfect when tires are off the ground . Yes on the pump for one gauge to test pump output. Usually about 1200-1500psi the system should be relieving internally. If pressure is not correct internal to the system there will not be enough hydraulic assist and greater effort from the driver will be required. No weight on the wheels should allow them to turn almost effortlessly. Near any service manual will have a power steering test setup included. 1 Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-424949 Share on other sites More sharing options...
Sdecker85 Posted June 10, 2019 Share Posted June 10, 2019 Yea I bet the pump is sh!tting the bed because with the wheels off the ground it steers like it used to when I bought it normally.but not effortlessly but now it is hard as heck. Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-424951 Share on other sites More sharing options...
Rob Posted June 10, 2019 Share Posted June 10, 2019 You need to discount the weight off wheels thoughts. If there is no resistance to the tires turning, there will be no rise in hydraulic pressure to force them to turn. Hydraulic flow determines how fast you can turn the wheels, hydraulic pressure determines how much effort the system requires from the driver meaning higher pressure equals less driver input. Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-424955 Share on other sites More sharing options...
JoeH Posted June 10, 2019 Share Posted June 10, 2019 With the wheels off the ground my 1973 Mack will turn effortless, and it has no power steering!!! The trucks weight on your tire contact patch is the only thing that generates resistance to turning the wheel. Unless you've broken the steering box, in which you'd likely feel a clunking when turning the wheel. Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-424961 Share on other sites More sharing options...
1965 Posted June 12, 2019 Share Posted June 12, 2019 Make sure your king pins are getting greased completely Quote Link to comment https://www.bigmacktrucks.com/topic/28398-mack-gu713-power-steering/#findComment-425095 Share on other sites More sharing options...
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