05 DMAX brakes lock up when turning

[automays]

I have a 2005 DMAX hauled in today. IT WILL ROLL IF the steering wheel is straight,But if you turn the wheel the brake pedal will depress and lock the brakes. Could this be a bad HYDROBOOST? or blocked return line?

[TBLAZER]

I have a 2005 DMAX hauled in today. IT WILL ROLL IF the steering wheel is straight,But if you turn the wheel the brake pedal will depress and lock the brakes. Could this be a bad HYDROBOOST? or blocked return line?

You need a hydrobooster,here is a doc ID and some info from GM.

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Document ID# 1686251

 

Subject: Hydro-Boost Brake Pedal Moves or Self Applies at Full Turns - keywords booster hydroboost press steering turn wheel

 

 

Models: 1988-2006 All Full Size Chevrolet Trucks and Utilities

 

1988-2005 Chevrolet Astro Vans

1988-2006 Chevrolet G Vans (including Express)

1988-2006 All Full Size GMC Trucks and Utilities

1988-2006 GMC G Vans (including Savana)

1988-2005 GMC Safari Vans

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

 

Condition/Concern:

On vehicles with hydro-boost, customers may notice during full lock turns or near full lock turns that the brake pedal will move down or self apply. This can be caused by the internal dump valve of the hydro-boost not seating properly due to contamination in the steering system. The hydro-boost assembly is not tolerant to certain types of contaminates that may be present in the steering system.

 

Recommendation/Instructions:

The Hydro-boost system is not serviceable, and must be replaced. Before replacement of the hydro-boost system, the entire steering system (power steering pump, lines, and the gear box) must be flushed to avoid reoccurrence.

[automays]

I appreciate the response TBLAZER. I felt like that was the problem, But everyone I talked to had never heard of one doing this. THanks again.