I have a 97` 4x4 SC w/4.6L . It has just turned 50,000 miles. About 6 weeks ago I startd hearing a noise at idle a kind of rattle hich pitch type . Something like spring steel a vibration sound. Nothing on inside the truck with windows up. Start the truck no noise till you hit the brake or if you had in gear then put in park it starts the noise. I`ve checked everything at least 12 times!! Finally found where the noise is coming from. BRAKE BOOSTER inside it. So I put on a new one ,still have noise , so I get the one from my dads truck which in his truck no noise, my truck noise still. If you plug the vac. line to the booster, no noise. How do I fix it???????? I need help. Does anyone else have this????
Thanks a head of time!!!
Lariat#1

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1997 Red/Silver F150 Lariat Flareside 3 Dr. SC..... ORP & Tow Package, Complete Lariat Option Package ,{APPEARANCE} GTS Projector Beam /Carbon Fiber Headlite Covers,AVS Tail Lite Slots & Door Sill Protectors,Flareside tail lites wired to work upper&lower lenses together,Owens Fg. Step Boards, Tinted Windows,Ford 2-Piece Bra,Lighted Ford Logo in Grill,20" Chrome Exhaust Tips,A.R.E Bed Cover Lid,Pendaliner Inner Tail Gate Protector,Zie-Bart Total Paint & Under Coating W/ Sounder Deadener Protection, Lariat #1 Plate under glass on Front Bumper,Custom made Ford Red Window Decals,Blue Tinted Rear Lic. Plate Protector,Blue Billet Valve Stem Caps, Ford Chrome Hitch Receiver Cover, HD Bed Mat, Red reflectors above Rear Bumper {PERFORMANCE} 4.6L WINDSOR Auto, 3.55LS, 4-Wheel ABS,Platinum 3 Spark Plugs,K&N Air Filter W/ modified stock MAF side air box,Custom Cold Air Chamber (Dam) to keep hot air from K&N Air Filter,Outerwears Blue Pre-Filter Cover,Ram Air Tube to K&N Filter,Tornado Air Man.,Perma-Cool Oil Filter Relocation Kit,Dual Exhaust System W/Stock Muffler,NAPA Ceramix Carbon Ceramic Premuim Brake Pads(Front),Goodyear Wrangler A/TS Tires,55 Watt Halogen(replacement) Reverse Lites, Pilot 55 watt Halogen (add-on) Reverse Lites on Hitch under truck,Driving Lamps upgraded to 55 Watt Cool Blue Halogen Bulbs,Pilot Bright Whites headlite bulb replacements 65/55 watts,Driving Lamps(Foglites) work W/ High Beams On & Driving Lamps(Foglites) also work (ON or OFF) W/ Park Lamps On W/Switched Relay, A.R.E Cover wired W/interior(dome) light wired to a mounted door jam switch thats wired to hood light,SurgeGuard by Calterm {AUDIO} Stock In-Dash Cass. W/6 Disc Changer & 2 Stock Speakers(back) & 2 Pioneer TS-A6865 3- Ways(front),Black felted inner front door speaker openings , all speakers dynomat lined,Trenz Billet #3 Antenna {SECURITY} Ford Total Security System W/ Motion Alarm All on factory Key Fob,Ford Warning Decals on Windows,A.R.E Cover & Hood also wired to Alarm System, Hitch Pin locking system This is LARIAT#1..... IN The Great State Of Indiana "Where more than corn grows in Indiana".........http://hometown.aol.com/terrylariat1...page/auto.html A Very Proud Member of ...www.f150online.com

 

Lariet
The only thing 2 boosters have in common is the vacume line. I would put a vacume gauge on that line & look for fluctuations in vacume. If there are, look for that problem. Good luck

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97 Lariet-sc-4.6-4x off road-auto-3.55 LS-
superchip-K&N-3"
pvc air box mod-Granetelli MAF

 

Did you replace the vacuum fitting on the booster? There should be a check valve in-between the booster and the manifold somewhere.

 

Anyone out there? That can solve problem?

 

With each booster a new check valve came with it. The only thing I know to do is put on another booster or take the truck to my Ford dealership & have them call Ford on the hotline. Thanks for your replies!!!

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1997 Red/Silver F150 Lariat Flareside 3 Dr. SC..... ORP & Tow Package, Complete Lariat Option Package ,{APPEARANCE} GTS Projector Beam /Carbon Fiber Headlite Covers,AVS Tail Lite Slots & Door Sill Protectors,Flareside tail lites wired to work upper&lower lenses together,Owens Fg. Step Boards, Tinted Windows,Ford 2-Piece Bra,Lighted Ford Logo in Grill,20" Chrome Exhaust Tips,A.R.E Bed Cover Lid,Pendaliner Inner Tail Gate Protector,Zie-Bart Total Paint & Under Coating W/ Sounder Deadener Protection, Lariat #1 Plate under glass on Front Bumper,Custom made Ford Red Window Decals,Blue Tinted Rear Lic. Plate Protector,Blue Billet Valve Stem Caps, Ford Chrome Hitch Receiver Cover, HD Bed Mat, Red reflectors above Rear Bumper {PERFORMANCE} 4.6L WINDSOR Auto, 3.55LS, 4-Wheel ABS,Platinum 3 Spark Plugs,K&N Air Filter W/ modified stock MAF side air box,Custom Cold Air Chamber (Dam) to keep hot air from K&N Air Filter,Outerwears Blue Pre-Filter Cover,Ram Air Tube to K&N Filter,Tornado Air Man.,Perma-Cool Oil Filter Relocation Kit,Dual Exhaust System W/Stock Muffler,NAPA Ceramix Carbon Ceramic Premuim Brake Pads(Front),Goodyear Wrangler A/TS Tires,55 Watt Halogen(replacement) Reverse Lites, Pilot 55 watt Halogen (add-on) Reverse Lites on Hitch under truck,Driving Lamps upgraded to 55 Watt Cool Blue Halogen Bulbs,Pilot Bright Whites headlite bulb replacements 65/55 watts,Driving Lamps(Foglites) work W/ High Beams On & Driving Lamps(Foglites) also work (ON or OFF) W/ Park Lamps On W/Switched Relay, A.R.E Cover wired W/interior(dome) light wired to a mounted door jam switch thats wired to hood light,SurgeGuard by Calterm {AUDIO} Stock In-Dash Cass. W/6 Disc Changer & 2 Stock Speakers(back) & 2 Pioneer TS-A6865 3- Ways(front),Black felted inner front door speaker openings , all speakers dynomat lined,Trenz Billet #3 Antenna {SECURITY} Ford Total Security System W/ Motion Alarm All on factory Key Fob,Ford Warning Decals on Windows,A.R.E Cover & Hood also wired to Alarm System, Hitch Pin locking system This is LARIAT#1..... IN The Great State Of Indiana "Where more than corn grows in Indiana".........http://hometown.aol.com/terrylariat1...page/auto.html A Very Proud Member of ...www.f150online.com

 

sound has a funny way of traveling around. is it possible the problem sound is in one of the brakes and the noise is traveling through the line? Just guessing. you know if you take it to the dealer, the sound will stop and they will look at you like you are crazy!
ever notice that the guys who know all the part numbers, statistics, or work for ford don't have any reply on things like this?

 

does the noise occur when u step on the gas ( blip the throttle to full , dont hold it there and best to be in neutral or on a road test ) to duplicate a loss of vacuum ? if so pull out the pcv valve out of the valve cover (leave connceted to pcv line ) i have came across pcv valves wich resonate throught the valve cover making a loud knocking type noise, without hearing the sound i am just telling u what i have came across, if the noise disappeares replace the pcv valve ( they are cheap anyway )and reinstall into the valve cover

 

Man, your signature is out of control. Lots of guess work with noises and vibrations good luck to you.

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98 F250 LD 5.4 dual exhaust, K&N, Big tires