Jump to content

Warning on holding brake while pressing gas pedal - damages steering?

Another JR
 Share

Recommended Posts

Another JR Senior Enthusiast

Another JR

Posted
Posted

Saw this warning in the owners manual for my 3500hd:

 


   { Warning
 Do not hold the brake pedal and press the accelerator pedal at the same time. Damage may occur to the power steering and power brake systems which could lead to reduced performance, up to and including loss of steering and brake assist.
 

 

Not that I do that when I drive, other than briefly on a steep hill start maybe, but does anyone know how the steering
system would be damaged by this?

 

Random Enthusiast

Random

Posted
Posted

I must have skipped over that part when I was looking through my manual, but it's really in there. If I were to hazard a guess, it's probably related to the variable steering on the higher level trims. Pressing the brake and throttle at the same time probably is a confusing thing for a system that trying to adjust based upon how you're driving.

KARNUT Senior Enthusiast

KARNUT

Posted
Posted

Hummm, times have changed. The only thing back in the day that potentially wore out doing that in moderation  was the back tires. 

  • Like 2
  • Haha 1
newdude Senior Enthusiast

newdude

Posted
Posted
12 hours ago, Another JR said:

Saw this warning in the owners manual for my 3500hd:

 


   { Warning
 Do not hold the brake pedal and press the accelerator pedal at the same time. Damage may occur to the power steering and power brake systems which could lead to reduced performance, up to and including loss of steering and brake assist.
 

 

Not that I do that when I drive, other than briefly on a steep hill start maybe, but does anyone know how the steering
system would be damaged by this?

 

 

 

 

Hydroboost.  Brake assist is provided via the power steering pump/hydraulic pressure.  It could be a scenario of over-pressurization of the booster or the ps pump and all of the hoses.  

  • Thanks 1
Random Enthusiast

Random

Posted
Posted

Same warning doesn't show up in the 2020 user manual, so I'm guessing it's a problem discovered before releasing the 2021's.

sheath Enthusiast

sheath

Posted
Posted

Thanks for bringing this up.  :cheers:

I use the brakes and throttle together off-road to load the suspension and get through difficult rocky situations with limited tire slip. 

Will need to look into this, as it's pretty important for me.  Funny the Dodge has hydroboost, but I've not had this issue, and I've run it through some pretty long rock stretches.  Will look into why it's an issue for the GM.  Maybe it will be simple, like adding an external cooler package (fingers crossed). 

Keith_Schumaker Enthusiast

Keith_Schumaker

Posted
Posted

I had a few funny thing happen when pulling out in my 21.  Mostly involving when I am sitting on a hill and I start on the gas pedal before I let off the brake,  the antilock brake system goes nuts and you hear the typical abs grinding noise as soon as the truck starts moving.  My truck also went nuts the one morning when I had to use the rumble strips for a bit because a tractor trailer wasn't paying too much attention to what he was doing.  The dash looked like a christmas tree with all the traction control and abs lights on and it wouldn't let me use cruise control until I shut the truck off.  I think GM puts the warning there to cover up their electrical gremlins.

  • 2 weeks later...
Stand By Enthusiast

Stand By

Posted
Posted

Hmmm. What would be the point of owning a truck then? That's a known tactic for gaining traction when on a boat ramp, an icy grade, stuck in mud, snow or sand. Im guessing my custom isn't an issue with this warning? I did get hun up in the sand once. Rocking the truck with wheels turned sharp got me into traction control errors and a service light. Fortunately after I got onto the road it reset itself after a short drive. Was worried I was gonna have to hit the dealer to clear a code 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,914
    Total Members
    8,960
    Most Online
    AidenVorpagel
    Newest Member
    AidenVorpagel
    Joined

  • Who's Online   1 Member, 0 Anonymous, 636 Guests (See full list)

  • Latest Articles

  • Posts

    • Grumpy Bear
      Sugar Bears 2015 GMC Terrain SLE-2 2.4 AWD

      By Grumpy Bear · Posted

      286,740 Mile Services   8/6/2026   New AC Compressor. Refrigerant oil and dye, evacuate and charge system.  New exhaust system from cat back.  New Iridium plugs plus replace #3 coil Repair/rewire headlamp wiring (passenger side) and replace all forward bulbs. Polish lenses of both assemblies.  Pull rear rotors, clean and adjust parking assembly. Inspect, clean and grease front calipers. Check pads and shoes.  4 wheel power bleed of brake system. Dot 4 Reset idle speed 50 rpm higher New Serpentine belt.    Will need new pads in the rear in about 5K more miles.    Tax Title and License out the door just short of a grand.    AC clutch had bitten the dust. 1 year warranty on the pick and save replacement. Thing will make a Polar Bear cry Uncle.  He spent quite some time on the wiring. It was in the harness and he does nothing half. I got off cheap. I have considerable more light down the road. Sylvania Silver Star replacements.  Gas seal between the porcelain and shell of plug #3 was blown, cooked the coil. That was the cold miss.  Love the new exhaust. I can sneak into the neighborhood again.  Nice to have a working parking brake again. Belle Tire never got it done. That was disappointing.    This was one of her bigger bills and still way cheaper than a payment even given the oil consumption. This thing cost me under a hundred a month in repairs and normal routine costs. What is my incentive to replace it? 🤔           
    • AidenVorpagel
      cam upgrade in CA

      By AidenVorpagel · Posted

      hello I recently bought a 2012 gmc 1500 with a 5.3 and have a AFM disabler on it I'm interested in doing a cam but I'm worried if I remove the AFM system I will fail smog does anyone have info if they are able to detect that or a work around to it (not talking about hot smogging) please let me know thank you  
    • B14Sierra
      Noise after AFM delete

      By B14Sierra · Posted

      Did you figure it out?
    • B14Sierra
      Possible lifter tick after DOD delete

      By B14Sierra · Posted

      Update. I started chasing down my symptoms. Started first with pulling valve covers and looked at everything. Everything looked good and couldn't hear or feel anything different. Then a compression test. 240 psi or really close on each cylinder. I was worried I was a tooth off of timing. Not bad for an engine with 173,000. Granted I did put new heads on. I sprayed water around the injector area to see if I could hear a change. Nothing. I hooked up my new hp tuner which I should have done in the first place but I don't really know what I'm looking at just yet but am learning. I noticed the fuel trims were way off so that told me I have to have either a bad injector or exhaust leak. New injectors, so I did the shop vac on blower and in the tail pipe. Sprayed soapy water and found the exhaust flange on the drivers side was leaking. I didn't think it would be that considereding I pulled the heads and left the manifolds attached. I did have the transmission replaced not long ago. They must have not seated them properly but I guess I didn't notice. I put in new gaskets on both sides. Which by the way isn't a bad job but I had a hard time getting them to seal right. Took two attempts. Reset the fuel trims and the ticking is gone, engine runs smooth and acceleration has improved. Got to feel the real difference with that stage 1 cam. It's not that big of a difference but it does add a little more. It feels like how the truck should have been from the factory.
    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      Can it still be Assembled I?    Stribeck says that we need a certain amount of viscosity under conditions of load and velocity to prevent two surfaces of a know roughness from tearing each other asunder. And we have marketing trying to tell the masses that those two surfaced require less of that commodity due to more exact limits being placed on the same old clearances. We also know that there are limits to how hard something can before it becomes to brittle to be viable and to smooth to 'wet' the surface and that both of those conditions have been known and met since about the Second World War.    That viscosity value shook out at 10 centistokes at 212 F just under a hundred years ago.  Give this a look: [Anton Parr]     What is advertised is the Kinematic viscosity (mm2/s) or that which has been density adjusted but the value we are after is the dynamic viscosity (mPa.s) or true viscosity. You can see that this number is dependent on density thus base stock and temperature. You can also see that an SAE 30 doesn't reach that value in this example. However an SAE 30 that is at the upper end of the SAE 30 range; 12.5 cSt (mm2/s), might. 12.5 * .83 = 10.375 (mm2/s). If you could find an SAE 30 at the upper end these days.   Then there is the complication of viscosity modifiers or VII or VM, whatever you wish to call them. Polymers added to very thin base oils, perhaps 3 to 6 cP oils, that will meet the SAE *W30 spec at 'tested' shear rates and 100 C/212F  target temperature. So a polymer fortified base that is a fraction of the 10 cP requirement Stribeck insist upon.   This could be all well and good if those polymers didn't have two very problematic 'features'. They shear or loose viscosity both 1.) permanently and 2.) temporality. And they do both omitted in the advertised data with the distinct  purpose of deceiving the consumer of the actual operating state of the fluid. I've shown the example of Warren Oils COSTCO 10.91 cSt 5W30 formuation several times where the 100 C HTHS value is 6.9 cP!! That's the temporary shear down and with and SSI or shear stability index of 9.4 cSt. Note the intentional deception in using mixed units?    After a short while that 9.4 cSt oil has a viscosity corrected dynamic value of 7.8 cP. But as the SSI is still within the range of an SAE *W30 whose lower value is 9.3 cSt.    This allows them to continue to call this SAE 16 weight oil a 30 weight, the cake, and still meet the API requirements for fuel efficiency IMPROVEMENT mandated by the EPA. The eating of the cake. By the time you've worn out your motor doing the responsible thing by adhering to the warranty requirements, (the stick), you get deprived of the carrot, wear control. So sad, to bad.   So what can be done? Do I need actually say? [Anton Parr]       Even this must be monitored if the oil is on the low side and the VII an organic or you opt for a 0W40 with an even lighter base oil and more / higher MW VII. (Note the lower density of the 40 weight versus the SAE 30 mono-weight?)    There is another workaround. Temperature. An SAE *W30 run at a bulk temperature of between 180 and 195 F.    Being the belt and suspenders sort I am I do both. Run it cook and run it heavy.    In Part II I'll work the AW package. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...