Really nasty hopping up and down....

[BushWakr - RIP]

I have developed a nasty 'hoping' between 60 and 72kmh. The truck feels like I have a tire "throughing" but when jacked up and let to run free it is perfect. The steady bearing seems ok too. I have a small tool box on the floor boards behing the passenger seat and the thing literally jumps up and down. This is noticable as I go up through 60>70 kph but is the worst as I come down through the same range. Its not noticeable in the steering wheel just seat of the pants rear end hop sensation. Strangest **** thing I ever seen. Any ideas???? Help!!

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93. 5 D250 4X4,HD Spring Pkg, Rancho 7000's, Rear Swaybar,Dual Shock Front Stabilizer,BD Injectors,31/2" Mandrel bent exhaust,16cm 'Hot End',Modest Pump Tweaks/Timed,K&N Air,Isspro Pyro,Tach,transmission Temp,Auto Meter Oil Filled Boost Ga. , 3:54's, 4 Speed Auto, Clubcab, Aftermarket Reclining Buckets w/ctr Drop Down seat/console, Black over Silver, 21psi,285-65R-16's,American Racing Clear Coat Mags, Amsoil 15W-40HD Marine,12,000 lb. Warn Winch,KC Spots. 101,300 Kms (63,000 mi's).

 

[unclebilly]

Drive really slowly through a smooth asphalt parking lot. Does the truck still seem to go up and down a bit? Often this can be the result of a tire starting to separate.

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91. 5 CTD 4X4, 5" Stacks, Tweaked Pump, 33" Boots (in the summer), Unlimited Slip,
Big, Bad Dodge

 

[R.E. Miller]

I have had the same problem off and on, I'm thinking that my spring bushings are shot. Don't know though, love weird problems.

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1992 W-350 Club Cab Dually 3. 5" Jardine, Swiss cheese air box
1992 W-350 8' contractors dump with 3. 5"BD exhaust, 16cm^2 housing, DI pyro&boost
Russell

 

[Scot]

Do not forget to have the tire shop check the wheels and make sure they are not bent. When I bought mine, it would shake paint.
Two rims were bent.

 

[Gary - K7GLD]

A tire can LOOK perfectly round, and STILL be WAY out of balance. Have you had the tires in the shop to check balance? Is it possible you lost one of the balance weights, causing your problem?

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http://community. webshots.com/user/davison71 Early '91 250, 727 AT, 307 rear... Banks Stinger exhaust, intercooler... US Gear OD... Tweaked pump, upgraded radiator... MORE than a match for every new PS Ford encountered so far...

"Dura" WHAT? NOW I know where all those recycled beer cans go...

 

[BushWakr - RIP]

I had tires rebalanced about 8 months ago. Used tape weights due to clear coat mag.
No sign of missing weight. It had a slight hop even right after balance but has gotten worse since.
How can you tell if a tire is starting to seperate if it doesn't 'throw'????
Visually the spring bushings seem ok, normal age appearance. On smooth pavement there is still a noticable hop but I also notice that the hop seems more pronounced when I apply brakes to come down through 70-60. . not so noticable when i pull it down into 2nd and let engine compression do the work.
All input welcome on this one guys, i really need it.
Thanks for your thoughts.


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93. 5 D250 4X4,HD Spring Pkg, Rancho 7000's, Rear Swaybar,Dual Shock Front Stabilizer,BD Injectors,31/2" Mandrel bent exhaust,16cm 'Hot End',Modest Pump Tweaks/Timed,K&N Air,Isspro Pyro,Tach,transmission Temp,Auto Meter Oil Filled Boost Ga. , 3:54's, 4 Speed Auto, Clubcab, Aftermarket Reclining Buckets w/ctr Drop Down seat/console, Black over Silver, 21psi,285-65R-16's,American Racing Clear Coat Mags, Amsoil 15W-40HD Marine,12,000 lb. Warn Winch,KC Spots. 101,300 Kms (63,000 mi's).

 

[Shrimpy]

Just yesterday I had to replace my two front tires due to milage and one was starting to seperate on the inner belts. It started by shaking then pulling real bad to the right, tire was mounted on the left. Problem was seperation in trad was causing a noticiable hump on the outside edge of the tire. It would balance out O. K. , but would still cause pull and "hopping" at speed and braking. Problem now fixed.

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92 Ext. Cab, Auto trans. , 3. 54 Non-LS, Isspro Tach, 16 cm housing, PW injectors, no name 3 Gauge cluster, 230,000+ miles, straight pipe, old and abused but still running strong!!!!