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  1. #1

    Default 2007 Silverado issues...need help

    Well it's been a busy couple of months and I have neglected my truck a little bit I was going to do some repairs this weekend but I need some help on a couple issues.

    2007 Silverado classic crew cab 4.8 I bought it new

    The first issue is the brakes.... I have replaced the drum brake cylinders and inspected the calipers for leaks but for some reason this thing eats break fluid (a big bottle a week) I can't find the leak anywhere. When I push the brake pedal it makes like a bubbling noise. Not sure...any ideas? Master cylinder maybe? How do I check?

    The next is a knocking noise and a rough idle every time I stop to fast. It starts to idle really rough and make a knocking noise when I stop to fast or take a turn to fast what would cause this? It also will occasionally make a lot of white smoke too. I changed the oil and put some stabilizer in it but it still does it. The truck has about 180k and the last time I changed the oil it was super low... However there are no spots on my driveway so I assume it is burning the oil. I figured maybe the oil pump...any suggestions?


    The next thing is the check engine light come on occasionally then goes off after a bit. I haven't plugged in the code reader to see what it is but it happens often.

    The he last thing is the radio....for some reason the radio only uses the tweeter I am not sure if it's the head unit or what but sometimes it will randomly work but the majority of the time the only speaker that it uses is 1tweeter which drives me crazy. Should I just replace the head unit?


    Any and all help would be greatly appreciated

  2. #2

    Default

    My one suggestion could relate to multiple issues. Check your brake master cylinder for piston seal leaking fluid into the vacuum booster.
    This could explain fluid loss and rough engine performance and white smoke......

    Not saying it is, but it seems plausible considering the symptoms you are describing.

    To check it, you could try and pull the vacuum hose loose at the motor end and see if you have any brake fluid in the line. Otherwise you would need to pull the master cylinder off and check for fluid leaks from the seal.
    If the MC is the source, I can't begin to suggest how to clean the booster. I know that they can be very dangerous to take apart.
    2010 Silverado LT 1500 5.3L 4X4
    '95 BMW K1100LT
    '97 BMW K1100LT

  3. #3
    Jr. Engineer
    Join Date
    Oct 2013
    Location
    weedsport, NY
    Posts
    212

    Default

    I'm pretty sure its the MC! Loosen the two bolts that hold it to the booster, and tip it up, if there is fluid behind there, its the MC. If you take the booster vacuum line off and it has fluid in it, then you might as well change the booster too!
    Just my .02cts worth!

  4. #4

    Default

    I agree with checking the mc. check for fluid running doen the front of the booster where the mc mounts to it. If no fluid there, then look under your dash. Look where the rod from the brake pedal goes thru the fire wall. Many times when a MC leaks it will leak into the booster and the booster leaks into the cab thru the area I described. Burning oil usually makes blue smoke, not white. White is coolant or water burning.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors, http://www.gmtruckclub.com/forum/sho...5-GMC-Yukon-XL
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  5. #5

    Default

    Yea that would make a lot of sense the check engine has the code that its running too lean but it would go away after diving a few min or sitting for a while. Il check it tonight. Would it just be easier to replace the booster and mc rather than fixing? They are $30 on ebay used.

  6. #6

    Default

    Quote Originally Posted by Txtruck84 View Post
    Yea that would make a lot of sense the check engine has the code that its running too lean but it would go away after diving a few min or sitting for a while. Il check it tonight. Would it just be easier to replace the booster and mc rather than fixing? They are $30 on ebay used.
    does it have a vacuum booster or the hydro booster? I would not put used on. It is your brakes, not worth the risk. You might have the same issue when you install the used parts. there were different vacuum boosters sold for that year, rpo codes: JC3, JF3, . each code had a different booster. So, you can not guarantee that the one on ebay is correct. you may be better off searching for parts for an 2006 model as yours is a classic and the same as the 06. Most parts stores do not have data base information of the "classic" models of any given year so searching the previous year usually nets the correct results.
    Last edited by Pikey; 02-12-2014 at 12:55 PM.

  7. #7

    Default

    Quote Originally Posted by Pikey View Post
    does it have a vacuum booster or the hydro booster? I would not put used on. It is your brakes, not worth the risk. You might have the same issue when you install the used parts. there were different vacuum boosters sold for that year, rpo codes: JC3, JF3, . each code had a different booster. So, you can not guarantee that the one on ebay is correct. you may be better off searching for parts for an 2006 model as yours is a classic and the same as the 06. Most parts stores do not have data base information of the "classic" models of any given year so searching the previous year usually nets the correct results.
    How do I find the codes for the rpo?

  8. #8

    Default

    Quote Originally Posted by Txtruck84 View Post
    How do I find the codes for the rpo?
    Inside your Glove Box is a White Tag/Sticker....which is the Service Parts I.D. Tag(Pictured Below)and on it you will see your Vehicles Vin # Number and a Series of Letter's and Number's which are RPO Codes.....which stands for Regular Production Options...In Short what your Vehicle came with from the Factory....and you'll be looking for those RPO Codes that Pikey Mentioned Above,


    Here's the Service Parts Identification Label



    If go to the Link Below, and Enter your Trucks Vin # Number, it will Show you All the Features your Silverado Came with from the Factory, along with All of the RPO Codes, for those Features.
    Link,



    Last edited by 99'HEARTBEAT; 02-12-2014 at 09:10 PM. Reason: Added Infor.

    MIKE


    99"SILVERADO
    5.3 l 3.73 l G80
    BLACK BEAR CUSTOM TUNE
    SNUGTOP l COLORMATCH l KATZKIN










  9. #9
    Legend

    Join Date
    Sep 2010
    Location
    everett, massachusetts
    Posts
    1,466

    Default

    before you buy parts follow the instructions given to determine what you need.

    if the master is leaking brake fluid into the brake booster then you will need a new master and a brake booster. these are items you DO NOT FIX .....

    Also you will need to replace the vacuum line from the booster to the intake vacuum port... If this is indeed the failure you have you may also have other problems cause brake fluid is destructive to rubber type parts..O2 sensors could also be damaged....

  10. #10

    Default

    Txtruck84,

    I am sorry to hear that you are experiencing an issue with your vehicle. As a customer service representative, I'm not able to provide much in the way of do-it-yourself information, so I'm glad to see forum members are beginning to step in with feedback. If you have any lingering concerns please private message me.

    Jennifer T.
    GM Customer Care

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