Hydroboost problems

Discussion in 'Engine & Drivetrain' started by Matahoe, Jun 5, 2018.

  1. Matahoe

    Matahoe Full Access Member

    Posts:
    237
    Likes Received:
    59
    Joined:
    Jan 27, 2016
    Location:
    Grand Rapids, Michigan
    Name:
    Matt
    Hey guys I think my hydroboost isn't working correctly. I was on the road going about 45mph and put the truck in neutral. I then stepped on the the brake a few times to deplete the reserve canister for the hydroboost. As expected the brake pedal became hard and the pedal force required to stop the truck was hard.

    I then started the truck while still in neutral and put it in drive. I drove down the road at 45 for a half mile or so. Then came up to a light and needed to stop but the hydroboost brakes wouldn't work at all. It was as if the reserve was depleted but this time the engine was running.

    I was unable to find anything similar to this scenario while reading online troubleshooting steps. I am left scratching my head on this one. If anyone can help or point me in the right direction that would be great.
     
  2. clandr1

    clandr1 Full Access Member

    Posts:
    489
    Likes Received:
    41
    Joined:
    Apr 20, 2012
    Name:
    Chris
    Free bump, I have no experience so I'm unable to help.
     
  3. swathdiver

    swathdiver Full Access Member

    Posts:
    4,379
    Likes Received:
    2,852
    Joined:
    May 18, 2017
    Location:
    Treasure Coast, Florida
    Name:
    James
    So did the pedal come back up?
     
  4. Matahoe

    Matahoe Full Access Member

    Posts:
    237
    Likes Received:
    59
    Joined:
    Jan 27, 2016
    Location:
    Grand Rapids, Michigan
    Name:
    Matt
    Not exactly sure. I will test it again.

    I might have confused having booster reserve with the engine off and on. I did come to a rolling stop with the engine off I know that...but I will make sure and list the scenario step by step.
     
    swathdiver likes this.
  5. Chubbs

    Chubbs Full Access Member

    Posts:
    578
    Likes Received:
    314
    Joined:
    Jun 24, 2017
    Name:
    Joe
    If you are attempting any kind of DIY repair or replacement, even diagnosis of hydraulic assist braking, aka hydroboost, at least buy a workshop manual. I looked up braking diag procedures and there is just a vast amount of literature there. I pulled up this Chiltons online library and highly suggest that you invest just so you have a starting point.

    I can tell you right now you are going about this all wrong if you are cutting the ignition while driving down the road and attempting to stop the vehicle. Prob get somebody killed if you continue. Regardless, a manual instructs with the steps & techniques relevant to diagnosing specific symptoms so that you aren't doing random shit as documented in the original post.
     
    Jasoncapps71 and swathdiver like this.
  6. Matahoe

    Matahoe Full Access Member

    Posts:
    237
    Likes Received:
    59
    Joined:
    Jan 27, 2016
    Location:
    Grand Rapids, Michigan
    Name:
    Matt
    I've already looked in the manuals and also online in other forums. The reason I posted the question is because there is no directly comparable scenario in the troubleshooting literature or elsewhere that I have found. I'm not going to kill anyone being in neutral with the ignition off. Its all pretty controlled. Been doing vehicle mechanics for over 25 years. I am still able to steer and brake....it's just harder. Also, there is no one else on the road at the time as well of the tests. The only person with a remote chance of being killed would be myself but Im 99.99% sure that isn't going to happen at 45 mph less.
     
  7. Rocket Man

    Rocket Man Sometimes A Dumbass Supporting Member

    Posts:
    7,793
    Likes Received:
    9,368
    Joined:
    Dec 25, 2014
    Location:
    Oregon
    Name:
    Mark
    There's no comparable scenario for a reason. Who tries to test a power steering and brake system with no power? That would fall under an emergency scenario where your engine dies and you need to get stopped without crashing which is possible but requires a lot of effort. I don't understand what you're trying to do.
     
  8. swathdiver

    swathdiver Full Access Member

    Posts:
    4,379
    Likes Received:
    2,852
    Joined:
    May 18, 2017
    Location:
    Treasure Coast, Florida
    Name:
    James
    I haven't driven a hydroboost braked car since the 1990s with my '80s Olds and Buicks. Now if memory serves, if the car were to stall the pedal and steering would get hard but could still stop with great effort. Once the engine was restarted, I'm trying my best to recall here, I think it took a few pumps of the pedal to get firm again.

    Get yourself an AllDataDIY subscription for your truck and get access to the shop manual and trouble shooting guides.
     
  9. ezstriper

    ezstriper Full Access Member

    Posts:
    110
    Likes Received:
    31
    Joined:
    Nov 2, 2010
    Name:
    Rob
    there is no reserve that I know of, hydro boost uses P/S pressure so as long as the engine is running and belt is on system charges as long as parts working
     
    swathdiver and Rocket Man like this.
  10. Rocket Man

    Rocket Man Sometimes A Dumbass Supporting Member

    Posts:
    7,793
    Likes Received:
    9,368
    Joined:
    Dec 25, 2014
    Location:
    Oregon
    Name:
    Mark
    That's what I would think too. The power steering pump is used for hydraulic pressure assisted braking as oppoeed to vacuum assisted and I know from experience that the power steering quits when the engine dies so I would expect the power brakes quit also. The systems are tied together.
     
    swathdiver likes this.

Share This Page