Mystery Solved Re Noise Under Box
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Joined: Jan 2001
Posts: 43
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From: Regina Canada
Mystery Solved Re Noise Under Box
There have been several posts regarding strange knocking or clunking noises under the box. Some posts cite low speed parking manouvers, and irregular occurance of the knock
Finally found the source of the problem with my 97
Inspect the front bushing insert and forward spring hanger of the rear springs. Take a pry bar and try to move the spring back and forth ie. left to right in the hanger. If the spring can move, or if upon inspection the spring main leaf end loop is not centered in the hanger then the rubber bushing has lost its bond/fit to the inside diameter of the spring end loop. Depending upon the combination of forces ie. braking, acceleration, cornering and where the rubber has lost its bond the spring loop determines how and when the loop will interfere with the hanger bracket.
Here is the solution, have a reputable spring service shop replace the bad bushing as I did or you could try a poor boy approach to install a high durometer rubber washers on each side of the loop in the hanger and reinstall the bolt.
This should fix the problem of the mystery 'clunk' driving you nuts! Local spring shops report this is a common problem and that most people are not aware of the defect.
On another note for the jokes thread I saw a bumper sticker in an obscure gas station
"This Is Ford Country:
On a Quiet Night you Can Hear The Chevies Rusting"
Regards
Dave
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97 F150 4x4 Ext Cab Long Box 4.6L Auto, stock, in showroom condition Oxford White/Gold BedRug
Finally found the source of the problem with my 97
Inspect the front bushing insert and forward spring hanger of the rear springs. Take a pry bar and try to move the spring back and forth ie. left to right in the hanger. If the spring can move, or if upon inspection the spring main leaf end loop is not centered in the hanger then the rubber bushing has lost its bond/fit to the inside diameter of the spring end loop. Depending upon the combination of forces ie. braking, acceleration, cornering and where the rubber has lost its bond the spring loop determines how and when the loop will interfere with the hanger bracket.
Here is the solution, have a reputable spring service shop replace the bad bushing as I did or you could try a poor boy approach to install a high durometer rubber washers on each side of the loop in the hanger and reinstall the bolt.
This should fix the problem of the mystery 'clunk' driving you nuts! Local spring shops report this is a common problem and that most people are not aware of the defect.
On another note for the jokes thread I saw a bumper sticker in an obscure gas station
"This Is Ford Country:
On a Quiet Night you Can Hear The Chevies Rusting"
Regards
Dave
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97 F150 4x4 Ext Cab Long Box 4.6L Auto, stock, in showroom condition Oxford White/Gold BedRug
Senior Member
Joined: Nov 1999
Posts: 1,177
Likes: 0
From: Carolina, Puerto Rico, USA
I will check mine immediatly. Thanks for the post.
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My Ride: 1998 F150 4x4 Lariat Supercab Flareside 5.4L in Oxford White/gold, ORP, Tow Package, 3.55 Gears.
Modifications:
Split Fire Spark Plugs
K&N FIPK
Gibson Supertruck Exhaust System
Stepshield door sill protectors
Performance Accesories 3" Body Lift
Superlift 3" lift blocks
Performance Lift Lips
Gabriel Gas Ryder LT VST Shocks
Daystar Front Anti-sway Bar Polyurethane Bushings
Heckethorn Steering Stabilizer
35x12.5R16.5LT BFG All Terrain KO's
16.5x9.75 American Eagle 589's.
Photos at: http://www.communicomgroup.com/jmtruck
------------------
My Ride: 1998 F150 4x4 Lariat Supercab Flareside 5.4L in Oxford White/gold, ORP, Tow Package, 3.55 Gears.
Modifications:
Split Fire Spark Plugs
K&N FIPK
Gibson Supertruck Exhaust System
Stepshield door sill protectors
Performance Accesories 3" Body Lift
Superlift 3" lift blocks
Performance Lift Lips
Gabriel Gas Ryder LT VST Shocks
Daystar Front Anti-sway Bar Polyurethane Bushings
Heckethorn Steering Stabilizer
35x12.5R16.5LT BFG All Terrain KO's
16.5x9.75 American Eagle 589's.
Photos at: http://www.communicomgroup.com/jmtruck