I left the house this afternoon and the truck seemed sluggish. After driving a couple of miles and letting it warm up it still seemed to take a lot of accelerator to get it to go so I pulled over to check it out.

What I found was, every time I turned the steering wheel sharply the brakes would activate. You could see the brake pedal go down. Took a while to get it turned around to get back home.

You can bring the truck to a complete stop just by turning the wheels. Anyone out there run into something similar or have any ideas? Truck has 4600 miles on it and has run perfect till now. Took it on a 200 mile trip the other day and it ran and performed great, no indication on trouble till I started it today.

The power steering and the breaks are linked in these trucks, but they are not supposed to do that, it would appear that something is malfunctioning. I know that under hard breaking the steering gets a bit tight, but I have never herd of it going the other way.

It is strange. You turn the wheel and watch the brake pedal go down by itself. It will stay down till the pressure is off then come back up. I could understand if the brakes failed because the pump was bad but to have the brakes lock themselves is just weird. Hope someone has some ideas.

I'll nurse it into the dealers monday morning but would like to have some knowledge about it before I go.

That certainly is strange, keep us posted

I wonder if this is what mine is doing?? I can feel the truck pull sometimes when I am turning and the wheels will act like they are trying hop. Was thinking it was the rear end but not sure. Might have to get mine looked at as well.

This might sound stupid. Are you in 4wd??

Seen it before, accedently put it in 4wd and drive around. Very diffecult to make full turns at idle.

Fill out your signiture, so we know what kind of truck we are talking about.

Did a little test before it got dark out. Started truck in driveway, put it in drive and pointed it straight. Let it idle down the drive without touching any pedals. It moved free, turned the steering wheel hard left, brake went down and truck came to a stop, straightened wheel and brake came up and truck idled down the drive. Did the same turning hard right and truck again came to a stop with brake pedal going down. As soon and you straighten the wheel the brake pedal comes back up and the truck again moves off.

I can't see how it could be the anti-lock brakes cycling or the limited slip rear locking up. Has to be in the pump. Checked the fluids and both brake and power steering are where they are supposed to be, but something is causing the brake to activate when there is pressure on the power steering.

Checked the 4-wheel drive. Haven't used it but once since I bought the truck and that was a while ago. I did press the 4 wheel button, let it roll then pressed the 2 wheel while I was playing with it in the drive to see if it had accidentally been turned on.

It does feel similar to my old ford chattering through a tight turn with the wheels locked, but it is 100% the brakes.

Checked the 4-wheel drive. Haven't used it but once since I bought the truck and that was a while ago. I did press the 4 wheel button, let it roll then pressed the 2 wheel while I was playing with it in the drive to see if it had accidentally been turned on.

It does feel similar to my old ford chattering through a tight turn with the wheels locked, but it is 100% the brakes.

since you can reproduce at will, the dealer should be able to :grd: & get you back on the road pretty quick...

I know this isn't the problem, but it reminded me of the time I added 75 model chevy disk brakes to my 70 model blazer. I had to do some modifications (rotate mounting bracket) because in a tight turn the brakes were getting pressed against the steering knuckle and compressing the cylinder just enough to lock up that side.

It's faulty valve. Just had mine fixed at about 10k miles. Get it in and fixed immediatly. Your brakes or power steering can fail or even worst at the same time. It has happened to me and a couple others on this forum.

Truck is going into dealer this afternoon. Service manager there said he had never heard of this one. I don't like being the first on the block to experience something new. Rather have a nice regular problem everyone has seen a thousand times and is an easy fix. Just the luck of the draw I guess.

It's faulty valve. Just had mine fixed at about 10k miles. Get it in and fixed immediatly. Your brakes or power steering can fail or even worst at the same time. It has happened to me and a couple others on this forum.

I was worried that the whole system could fail. I will drive it in today because I can get there on straight no sharp turn roads and it seems fine unless the steering wheel is turned sharply. I will drive slow and very careful, the dealer is about 6 miles away.

Here's what is on the write up from the dealer. They found a faulty flow control valve. They replaced a spring and oring. If they are unsure they can call my dealer at (616) 784-8400 and ask for Rich. Good luck.

Took it in to the dealer last night will see what they say later today.

Well?

The suspense is killing me!

im curious of this as well

I got home last night after they closed and didn't get a chance to talk to them, will call today and get report.

Couldn't talk to the tech, but the Hydro-Booster was replaced. Want to find out exactly what failed if possible. Was it just an o-ring or valve or did the whole thing come apart. Be interesting to know. Either way they replaced it with a new one.

One good thing for everybody else is, the guy I talked to wasn't the tech that worked on it, but he said they have only seen this a couple of times and they work on a lot of trucks. There was a recall on the Booster for the 2005 Yukon but that was for breaking and leaking the fluid out. Don't know if they would use the same booster in the trucks that they used for the Yukon.

Talked to several people before I took it to this dealer, reputation of dealer seems to be that they have really good mechanics, are a little on the expensive side and are slow moving from vehicle to vehicle but also fix things right the first time. Friend of mine has an 01?-02? Duramax with 195,000 on it and has had everything done to the truck there. Claims everything they have looked at for him has come back fixed right.

This is the only thing I could find and it wasn't what happened to mine but may be related.

2006 GMC SIERRA Recall ID from NHTSA: 05V455000
Auto Recall Date: 20051005
Vehicle Component: STEERING:HYDRAULIC POWER ASSIST:HOSE, PIPING, AND CONNECTIONS
Estimated Vehicles Affected: 123592
2006 GMC SIERRA Defect Summary:
CERTAIN PASSENGER VEHICLES MAY HAVE BEEN BUILT WITH A POWER STEERING HOSE THAT IS NOT TO SPECIFICATION. UNDER EXTREME STEERING MANEUVERS, SUCH AS TURNING THE STEERING WHEEL FULLY TO THE LEFT OR RIGHT WHILE BRAKING, THE HOSE MAY FRACTURE AND LEAK FLUID.
Defect Consequence:
IF THIS WERE TO OCCUR, POWER STEERING ASSIST WOULD BE LOST AND INCREASED STEERING EFFORT WOULD BE REQUIRED. ON VEHICLES EQUIPPED WITH HYDRO-BOOST POWER BRAKES, IT COULD ALSO RESULT IN LOSS OF POWER BRAKE ASSIST AND INCREASED BRAKING EFFORT WOULD BE REQUIRED. IF THE POWER STEERING FLUID SPRAY WERE TO SPRAY ONTO HOT ENGINE PARTS, AN ENGINE COMPARTMENT FIRE COULD OCCUR.
Remedy:
DEALERS WILL INSPECT THE POWER STEERING HOSE(S) FOR TWO SUSPECT DATE CODES AND REPLACE THEM IF REQUIRED. THE RECALL WILL BEGIN ON OCTOBER 14, 2005. OWNERS MAY CONTACT CHEVROLET AT 1-800-630-2438, GMC AT 1-866-996-9463, BUICK AT 1-866-608-8080, CADILLAC AT 1-866-982-2339, ISUZU AT 1-800-255-6727, OR HUMMER AT 1-800-732-5493.
Notes: GENERAL MOTORS CORP., 05086

Final: They have a service sheet on the Hydro Boost. There is a two way valve that can fail and if it does the brakes will activate when the steering wheel is turned. They are supposed to pull the boost and replace it with a new one, flush the brake lines and replace all fluid. So my truck has a new boost and all new brake fluid. Acts great again.

My final thought, if you are one of the guys whose truck seems to be dragging when you turn you should get it checked out. It would seem logical that the valve may work but leak enough to cause the brakes to activate and they do have a service bulletin on this problem. The one tech told me they hadn't seen but a couple of these, but if there are enough out there to deserve a service sheet then it is something to be watched out for.

Good luck to everyone.

Final: They have a service sheet on the Hydro Boost. There is a two way valve that can fail and if it does the brakes will activate when the steering wheel is turned. They are supposed to pull the boost and replace it with a new one, flush the brake lines and replace all fluid. So my truck has a new boost and all new brake fluid. Acts great again.

My final thought, if you are one of the guys whose truck seems to be dragging when you turn you should get it checked out. It would seem logical that the valve may work but leak enough to cause the brakes to activate and they do have a service bulletin on this problem. The one tech told me they hadn't seen but a couple of these, but if there are enough out there to deserve a service sheet then it is something to be watched out for.

Good luck to everyone.

Can you get the service bulletin number and put it on here?

Thanks

I didn't look at the number on the bulletin he showed me but the bill has "repaired per doc #1686251. I don't know if that is the service bulletin number or not, but think it probably is. I just read the paper he showed me and made sure they had done what it said to do.

Hope that helps.

I left the house this afternoon and the truck seemed sluggish. After driving a couple of miles and letting it warm up it still seemed to take a lot of accelerator to get it to go so I pulled over to check it out.

What I found was, every time I turned the steering wheel sharply the brakes would activate. You could see the brake pedal go down. Took a while to get it turned around to get back home.

You can bring the truck to a complete stop just by turning the wheels. Anyone out there run into something similar or have any ideas? Truck has 4600 miles on it and has run perfect till now. Took it on a 200 mile trip the other day and it ran and performed great, no indication on trouble till I started it today.


i kind of have the same problem,feels like brakes are engageing when turing left or right..it doesnt seem as extreme as your problem..

I don't know much about valves, can they leak enough to cause this problem or do they have to fail completely?

There are other reasons trucks can feel like they drag during a turn. 4X4 engaged, limited slip rears can feel like drag during sharp turn from stop. But the hydro boost failure is a known cause and should be checked out. I wonder how much wear I did to the brakes in the short time mine was engaging?

This just happened ot me today. The truck will not move when steering and a nasty power-steering wine. I have an 06 w/ 6K miles on it. I guess it is time to workout the bugs. Calling the dealer on monday and the truck stranded in the some parking lot.

As said the power steering pump pressure is the "assist" or the "power" portion of your brakes, same principal as the vacuum booster.. Sounds like an internal problem in the hydroboost mc..

Well hey :D I'm not nuts afterall. I picked up my truck last month and it did it the first day. When backing up with the wheel at full lock left or right it the front tires would chatter like it was in 4WD. Got so bad that I put it on jack stands to make sure the 4wd wasn't engaged and the lights were wrong. My wife said I was crazy until she was backing out of my parking lot and felt it...and I saw the tires lock and slide on the ice.

Looks like my fix-it list is getting longer for the dealer.