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post #1 of (permalink) Old 03-25-2004, 09:57 AM Thread Starter
 
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Wierd noise while driving

I know this will be hard to explain but I was wondering if anyone could offer up some suggestions. For the last 2 days I have been having some small vibrating noises from what sounds like under the hood. I first noticed it upon start up the other night. It dosen't seem to care if the engine (truck) is warm or cold on start up. When I am in drive but stopped I hear a small pulsing noise and feel the "noise" in the steering wheel and brake pedal. I checked under the hood and found that my air compressor had a cracked bracket. I took it out and the noise is still there. I was thinking that it maybe the brakes? Maybe the power steering. The sound is nothing loud, more like a little grinding or rubbing. I just wanted to stop something before it turned into something big.
One thing that I also noticed is that if I am in park with the engine running and I push the brake pedal down all the way and then let go the eninge loses and them picks up. It seems like there is a little drag. IS this normal. I guess because I am hearing something I have never heard before I am paraniod. Thanks for all of the help and suggestions in advanced.
Michael
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post #2 of (permalink) Old 03-25-2004, 09:59 AM Thread Starter
 
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Re: Wierd noise while driving

BTW my belts are in good condition and are under tension. Could a pulley be going out? That noise that I "feel" can also be felt on the metal thing that the master cylinder is connected to. Maybe I need to fluch the whole system. Althought I don't think that would fix anything.
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post #3 of (permalink) Old 03-25-2004, 04:08 PM
 
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Re: Wierd noise while driving

Mike:

Here's what I would start with. I would get a stethoscope or a piece of tubing and begin checking around the pulleys, AC, PS pump, etc. You might be able to at least eliminate some parts in there. Also check for a vacuum leak while listening for the noise. With the motor loading down after the brakes are pressed, it may be a vacuum leak at your power brake booster. That's just some ideas. Hope it's nothing too bad.

Good luck
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post #4 of (permalink) Old 03-25-2004, 05:30 PM
 
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Re: Wierd noise while driving

same damn thing i was gonna say. the engine loaidng down indicates vacuum leak, but i dont know if that would make the noise/feel you're experiencing...but it could.to hear the vacuum leak you'll need either a mechanics stethoscope, or a piece of hose to listen to all parts of the vacuum line
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post #5 of (permalink) Old 03-25-2004, 08:28 PM
 
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Re: Wierd noise while driving

My truck is also loading down when i step down on the brakes at a stop i get the same loading down. My power steering seems to be loading down the engine too. When i get my truck back from the tranny shop i'll check vaccum lines.

What would be the best way to check them? Where would they be running to/from? Thanks!
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post #6 of (permalink) Old 03-25-2004, 09:29 PM Thread Starter
 
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Re: Wierd noise while driving

Vaccum? Is that the engine or the brakes? Sorry I'm not sure what exactly I should be looking for. Any help would be appreciated.
Thank you.
Darren:
Where did you take the Hoe? Did you get a good deal?
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post #7 of (permalink) Old 03-25-2004, 10:13 PM
 
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Re: Wierd noise while driving

its teh same vacuum. the vacuum that is used to assist the brakes comes from the intake of the engine. thats why when you hit the brakes and there is a leak, it leans out the engine wich reduces power.
look at the brake fluid resevoir then the master cylinder is below that made out of aluminum i guess. that goes into the "big round thing". well from the big round thing there is a plastic fitting and a black rubber hose thatsa boutt eh size of yuor middle finger. that is the vacuum line. one end at the brakes. one end at the engine. if i were doing it. I"d probably first try pulling that hose off and plugging it. then start the truck and hit the brake pedal. if it still does it...not youyr problem. if it stops, then the problem is in the brakes probably the brake booster. if you need more than that let me know
the vacuum line ois near #2

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File Type: jpg 1281962-brake booster.jpg (76.9 KB, 41 views)
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post #8 of (permalink) Old 03-26-2004, 09:43 AM Thread Starter
 
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Re: Wierd noise while driving

Wow nice diagram. I did notice the line going from the booster to the top of the engine. The noise has stopped for the time being. I didn't do anything to it and it just stopped. My brakes have always sucked, if there was poor vaccum could that be the problem with weak brakes. I know that bleeding and new brake lines would help but could a proper vaccum lead to a firmer pedal and more braking power? Thanks for the help. I will pull the line and check it out though.
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post #9 of (permalink) Old 03-26-2004, 09:45 AM Thread Starter
 
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Re: Wierd noise while driving

#40 in the picture, what is that thing called. I have had the truck for 3 years and the brake lights always stay on until I pull up on the pedal with my foot. Would replacing this part fix the light problem?
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post #10 of (permalink) Old 03-26-2004, 10:42 AM
 
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Re: Wierd noise while driving

that diagram is courtesyt of krayzie. he posted it a few montsh ago and i saved it. as far as weak vacuum goes. it'll just make it harder to press the brake pedal. it wont do much to gein you stopping power, it just helps you so you dont have to press the pedal so hard.
#40 does look like teh prake pedal sensor switch. they go for about $10 at the parts store. they are very simple on the inside, but just a PITA to replace because there isnt much space around them. i have done it on my truck...just to find out that the old one was fine. there was a fuse i didnt check.
mike, replacing this will not turn off the switchin the dash. i mean it could, but that light being on is generally indicating that there is a problem with the system....like the ABS isnt working, or low fluid...stuff like that
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