Jump to content

Hydro BOOST brakes

XSKIER
 Share

Recommended Posts

XSKIER Enthusiast

XSKIER

Posted
Posted

I've spent a couple of days searching Google and the forums looking for tsbs and complaints, so excuse me in advance if this is a well known issue. I've had my '17 2500HD CCSB 4X4 6.0 for six days and 230 miles now, and the braking is lame compared to my other vehicles. Out of curiosity, I gave the brake pedal a couple of pumps and the brake feel improved. Last year I had a '95 K3500 DRW 454 12' stake, replaced with 01 K2500HD RC 6.0 this year. So I'm familiar with what Hydro boost should feel like. I have not driven a gmt900 truck with Hydro boost, but I'm sure some of you have, and can weigh in.

 

#1 Has GM lowered the assist pressure to increase the operator input on the pedal?

 

#2 With an improvement in feel after a couple of pumps, there is likely some air bubbles in the system. How could I get a service advisor to bleed the brakes if no stored trouble codes are present?

 

#3. Should I just be content with my biggest, best, most expensive vehicle out of 4 giving me a lame brake pedal feel?

i82much Enthusiast

i82much

Posted
Posted

Just throwing this out there - I took my new 2016 out and decided to do a couple of panic stops, just to see how it did in the snow. Get a sense of how it handled when no one else was around. Anyway, the first time I did it, the truck stalled! I couldn't believe it. I did a few more and it didn't happen again. My guess is maybe my first panic stop was the first time the calipers were fully extended and now if you look in the reservoir I bet the level is just a smidge lower than it was when I first got it. But, it all seems fine now.

XSKIER Enthusiast

XSKIER

Posted
  • Author
Posted

Sounds like they need to be looked at.

Yeah, I was afraid of that. I already know that the selling dealer's service dept will try to evade a thorough look by the standard "functions as designed" or "no codes, can't fix what ain't broke". It's probably worth it to me to take it to some "diesel brother" type shop that is well experienced with this set up.

 

I did put about 100 miles on the '01 today, feels like a race car compared to the '17...

  • 4 weeks later...
XSKIER Enthusiast

XSKIER

Posted
  • Author
Posted

Now at 1250 miles with lame brakes still. The truck sat at the dealer from Monday afternoon through Friday afternoon to address my brake concerns. The service writer didn't know much about hydraulic brakes, so she drug me back to the bay where the "work" was performed. She introduced me to the man who did the work, then carefully watched over our conversation. The main tone of our conversation was a lot of deflection and marginalization of my brake problem. The tech removed the tires, and, in his words, "ran three things though it, no way there is air now". According to the paperwork it was .7 hr labor to bleed the brakes, and two quarts of fluid. They did not road test it, and told me the brakes are OK. After driving around the block, there is no change from when I dropped it off. So I went back and asked for a new master cylinder, if there truly is no air in the system, right? They told me that they would not install one if the truck is "ok". I told them that I would not put up with the lame brakes for the next 35/34,750. I asked, Can you give me a discount on a master cylinder that I can take home and put on myself? She replied, Nope, no discounts at the parts counter. So, I left. It looks like 171 retail and 93 rock auto, so I'll just order it in and put it on the truck next weekend.

 

Sent from my SM-G930V using Tapatalk

2016HD Enthusiast

2016HD

Posted
Posted

Must be an issue with your truck. My new 16 stops incredibly well. Will put you through the window if needed. For sure an improvement from My 2001 HD with hydroboost.

Maybe your brake pads didnt seat or break in properly.

  • Like 2
  • Thanks 1
XSKIER Enthusiast

XSKIER

Posted
  • Author
Posted

So,

 

I was fortunate enough to test drive a real world 16 DCSB 6.0 WT 4X4 with 15k mi. today. And guess what? Nice, responsive, hydro boosted pedal feel. Hopped back in my truck... lameo! Dropping it off at hopefully a better dealer in the morning.

 

Sent from my SM-G930V using Tapatalk

  • Like 1
crankman Enthusiast

crankman

Posted
Posted

Take it somewhere else. Brakes should be fixable. Its not normal my brakes are smooth as silk stop nicely.

XSKIER Enthusiast

XSKIER

Posted
  • Author
Posted

2nd dealer is putting on a master cylinder. I'm excited to see if this does the trick.

 

Sent from my SM-G930V using Tapatalk

XSKIER Enthusiast

XSKIER

Posted
  • Author
Posted

Got my truck back today. No charge, no work order, lame brakes. This time the pedal is more firm, but has less power assisted feel. When I pump the pedal, something feels loose. Almost like the actuator from the hydroboost unit is too short and not staying with the master cylinder piston. Now I need the truck to haul a couple of loads with my gooseneck trailer. So I won't be able to give it back to service until next week.

 

Sent from my SM-G930V using Tapatalk

  • 3 weeks later...
XSKIER Enthusiast

XSKIER

Posted
  • Author
Posted

Went to pick up my truck today. $715 for a new hydrobooster later, and there is a wonderful hiss coming from the steering column at idle. It goes away if you rev the motor or steer. The hiss doesn't change until there is 60-100 lbs force applied to the brake pedal, forcing the pump into pressure relief. So, I left out of there in another 1500. By now I will have been in a loaner longer than my own new truck. I still have the new truck payment though...

 

Sent from my SM-G930V using Tapatalk

  • 2 weeks later...
XSKIER Enthusiast

XSKIER

Posted
  • Author
Posted

Picked my truck up Thursday, no charge this time. This time the brakes work like a new truck! I'm happy with the end result, but quite miffed about the whole process. I think I might try to forward the repair bill up a level.

 

Sent from my SM-G930V using Tapatalk

  • Like 1
2016HD Enthusiast

2016HD

Posted
Posted

Picked my truck up Thursday, no charge this time. This time the brakes work like a new truck! I'm happy with the end result, but quite miffed about the whole process. I think I might try to forward the repair bill up a level.

 

Sent from my SM-G930V using Tapatalk

What did they do to get it all fixed? And there shouldnt be a repair bill?? Do you not still have warranty?

XSKIER Enthusiast

XSKIER

Posted
  • Author
Posted

What did they do to get it all fixed? And there shouldnt be a repair bill?? Do you not still have warranty?

I didn't even look at the last service record, but the highlights are:

1: Bleed brake system, warranty

2: Replace master cylinder, warranty

3: Check brake pads, OK., warranty

4: Replace hydroboost unit, customer pay

5: Replace hydroboost unit again, warranty

 

Each step, one week in the service bay. 2017 Silveraydo with 34.7 month/34.7k mile bumper to bumper warranty remaining. The GM warranty system is a joke. If there is not a TSB for your complaint, then you have to beg them, and pay them to fix it.

 

Sent from my SM-G930V using Tapatalk

  • Like 1

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

    342,903
    Total Members
    8,960
    Most Online
    RyGuy43
    Newest Member
    RyGuy43
    Joined

  • Who's Online   1 Member, 0 Anonymous, 440 Guests (See full list)

  • Latest Articles

  • Posts

    • davester
      2015 Silverado 3500 right rear turn indicator failure

      By davester · Posted

      consider doing electrical testing?  I would guess some power or ground wire/connection has a problem.   alldata.com has wiring diagrams, connector pinouts and diagnostic procedures you can use to find where the problem is.
    • davester
      My First Project and GMC has me stumped

      By davester · Posted

      can you tell if the reader is actually trying to get codes, and the pcm is reporting none, or is your reader just silently failing because it's not communicating with the pcm?
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      Any joy with this truck seems to be short-lived.   The CEL for P0172 ("bank 1" too rich) is now "intermittent".   I'm not sure where to check, or re-check, and my energy to keep chasing problems with junk is wearing thin. The P0172 seems to set as I'm coming to a stop, completely off the throttle, when fully warm. At least, that's what it's done the 3? times it's set.   Everything appears normal on the scanner EXCEPT long term fuel trim. There's only one bank on this vehicle because it's an OBD 1.5 with only one upstream O2 sensor. At idle, it's around -16.4% and will dip to -18% occasionally at idle or off-throttle. LTFT approaches 0 when throttle is held at 2500rpm. Short term appears normal, much closer to zero all the time. The LTFT tells me the engine is running rich at idle but compensating at higher load. But, why?   The EVAP purge valve doesn't appear to be leaking/sucking fuel vapor continuously. Is it sticking just as I come to a stop and the engine is choking on fuel vapor and sets the P0172? But that doesn't explain the persistently negative LTFT. Disconnecting the purge valve doesn't seem to make any difference.   I suppose that leaves another dang issue with the fuel injector. A leaking fuel pressure regulator, a new leak in the spider, or a leaking fuel injector/poppet valve I didn't see, or a small crack in one of the spider legs.   The vacuum line leading to the fuel pressure regulator doesn't have raw fuel in it. It doesn't even smell like fuel when it's pulled off, not until you suck air through it, then you can tell it leads to a fuel component. I'd consider that normal? Nothing is signaling this is a FPR issue from the outside, at least.   The oil smells like fuel but it's not building volume. I've noticed most oil in most engines smells like fuel to some degree so it's hard to say if the smell is an issue or not. Or if the engine just still smells like fuel because the crankcase was full of it a few hundred miles ago. But it's been changed twice since that original issue of the leaking fuel line dumping fuel into the intake.   Patience is running very thin. Every win seems to be accompanied by two steps backwards, or another issue that leads to removing at least the top half of the intake manifold. Enough! LOL
    • Chuck FB
      Tire pressure for 37s

      By Chuck FB · Posted

      First off you mentioned "Toyo Says" and then gave the pressures 45/50, was this some person at the tire shop that pulled those numbers out of his head ?   Now of course I can't know your exact axle weights front and rear, however I have much the same pickup as yourself other than not knowing your starting weight as per the pounds the truck rolled out of the factory at due to the options yours did or didn't come with or what you have added beyond the extra tire weight. The correct way to know 100% where a person is at is by weighing each axle with the typical weight the vehicle is driven with and that means taking into account passengers and making sure you figure in a full tank of fuel and a little grace for whatever you may put in the bed "groceries" !    I am looking at and not that it really matters as all the tire companies use the same charts anyway, but I am looking at the comprehensive Toyo tire chart in the section that your tire falls under and I know it sounds confusing but your tire is not an LT metric tire like your factory tire but instead because its a standard inch measured tire its under a different category called an LT floatation series tire. That makes a difference as LT metric tires they don't want to see run below 35 psi at highway speed where as with the LT floatation series it can be run down to 25 psi on the highway as long as the weight on the said size of tire is agreeable with or less than that minimum 25 psi. It blows many people away that how is this physically possible, an empty truck for one thing and larger tires with the same size wheel diameter have a lot more air volume so they can carry the same weight as the smaller tire with less air pressure.    So my truck, I have the stock 275/65R20 wheels and tires and I have a bit of weight in the box with a bak flip cover and a rubber bed mat and some tools and spare gas. The front of my gas truck weighs a bit more than some trucks of the similar spec due to double batteries and alternators. However with full fuel and just me in the truck I am weighted such that I can run 40 front and 35 rear and so that is what I have done since day one.    If I base your truck at or slightly below the weight of my truck, in theory with your tires going by the tire chart you might be right around a minimum of 30 pounds front and 25 pounds rear. Of course that would hit pretty much minimum cold inflation pressure one could run with that tire size and a near empty truck. If you have access to an accurate weigh scale to do individual front and rear axle weights I would suggest you do that and make sure your topped up with fuel and whatever else in the truck before you weigh it and then you will have a great starting point to work off of and figure out what your bare minimum pressures are you can safely run. If you do much in the way of hot weather high speed driving, bumping up a bit for a safety margin is never a bad idea but just depends on what type of driving you do. I will include the Toyo chart and the floatation series sizes start on page 31. Without a doubt at these pressures I am speculating at minimum wise for your truck, it would most certainly ride very different then it did when you were using 55 lb front and rear.     https://www.toyotires.com/media/pxcjubjs/application_of_load_inflation_tables_20200723.pdf
    • Snowcamo
      Possible lifter tick after DOD delete

      By Snowcamo · Posted

      Take an automotive stethoscope to the vacuum pump. Iirc those tick as well. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...