Truck Braking Problem Question

Discussion in 'Heavy Equipment & Pavement' started by travislakerat, Mar 18, 2008.

  1. travislakerat

    travislakerat LawnSite Member
    from Texas
    Posts: 28

    This is slightly off topic, but I figure many of you out there either have or had trucks with similar issues in the past and could potentially save me $ or time or both.

    I have a 98 Chevy dually and drive it pretty often ( I just bought this truck 4 months ago to keep from destroying my 04 F350). The truck drives and stops fine, but noticed this past weekend that when it had a load ( pulling about 8000 lbs) the truck didn't stop right. The brake pedal would almost touch the floor on hard stops and would only give 60-70 stopping force. After cleaning my pants (jk) I decided I need to investigate. Without a load no issues, but I pushed the pedal this morning while stopped and found I could push it almost to the floor and I hear some whining from the power steering pump. I drove it and it stops fine.

    So here is my question. Could it be the power brake booster? Is it the power steering pump? Could it be both, if so which one would you change first?

    Thanks in advance for any and all the ideas that you have. I don't really dig the idea of taking to the shop and paying double although I will instead of smashing into the back of some little old lady. I just bought a used dump trailer with a 15,000 lb capacity and while it has electric brakes, I need all the stopping power I can get.
     
  2. Gravel Rat

    Gravel Rat LawnSite Fanatic
    Posts: 9,544

    The first thing your truck has hydroboost what you are experiencing is normal what the problem is your back brake drums are out of adjustment.

    The first thing I would be checking for is brake adjustment and what you have left of your brakes. Chevy runs big shoes in the back of a Chevy 1 ton I think they are 13x3 shoes.

    With hydroboost your pedal is firm driving around M/T when you put a load on the truck harder you push on the brakes more fluid travels into the booster.

    The reason why your pedal traveled so far it is probably because your rear brakes are way out or they are thin brake drums and the drums expanded under the pressure.

    If you do all 4 brakes with severe duty brake pads and shoes your face will hit the windshield when you step on the brakes :laugh:

    Another thought could be your abs might be not working properly find a way if disconnecting it you don't need it.
     
  3. KTM

    KTM LawnSite Senior Member
    Posts: 492

    Like said above, check your rear brake adjustment. I think these Chevy's adjust when you back up and hit the brakes, you might need to do this several times, or they might be stuck. Jack back end up and behind the drum will be a rubber cover, pop that of and turn the star wheel until you feel resistance, then back off a few turns. Also GM trucks of these years are known for crappy feeling brakes/pedals.
     
  4. travislakerat

    travislakerat LawnSite Member
    from Texas
    Posts: 28

    Thanks for the input and re-direction on what I have been looking at. Now that you mention rear brakes I failed to mention this earlier. When I brought the truck home I noticed that the left rear set would lock up really easy with light pressure, but would not do this with heavier pressure. I have contiuned to drive it and this has went away. Maybe this could be the weakness in one side or the other. ???
     
  5. Construct'O

    Construct'O LawnSite Bronze Member
    from Sw Iowa
    Posts: 1,387

    First off check the brake fluid,then check for leaks.If low broke or rusted brake line,could have air in the system.Power boost might be leaking by also.

    Check the fluid in the power steering different problem:).

    Also as said above.Good luck:usflag:
     
  6. Dirt Digger2

    Dirt Digger2 LawnSite Silver Member
    from PA
    Posts: 2,396

    agree 100% you can spend hours looking for something wrong when it something as simple as your fluid level
     
  7. ffemt1271

    ffemt1271 LawnSite Bronze Member
    Posts: 1,285

    you might want to inspect the pads/rotors to see if they are glazed over, especially if it has been towing heavy loads before.
     
  8. travislakerat

    travislakerat LawnSite Member
    from Texas
    Posts: 28

    I just dropped it off at the brake shop. I figured it was probably be the rear brakes. It was. The right rear axle seal was busted and had grease on the right brake pad. So new pads, wheel cylinders and seals should have it fixed up. More than I wanted to spend ($600) but at least I won't be tied up one day trying to fix it. Thanks for all the input.
     

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