Hydro BOOST brakes

XSKIER · March 8, 2017

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?

redwngr · March 8, 2017

Sounds like they need to be looked at.

i82much · March 8, 2017

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 · March 9, 2017

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...

XSKIER · April 1, 2017

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 · April 1, 2017

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.

XSKIER · April 3, 2017

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

crankman · April 3, 2017

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

XSKIER · April 5, 2017

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

DMAXNAZ · April 9, 2017

I would think if they test drive yours and then one off the lot they should notice the issue.

XSKIER · April 11, 2017

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

XSKIER · April 27, 2017

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

XSKIER · May 7, 2017

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

2016HD · May 7, 2017

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 · May 7, 2017

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