F-600 Bounces loaded

[Chaser95]

My newly acquired 79 F-600 has a bouncing problem. 370 5 speed with two speed rear, 16' grain bed with hoist, 9.00 x 20 tires on Dayton style wheels. Rides like a Lincoln empty, but with 7-8 tons on it develops a vibration and bounce at about 38-45 mph. This is not a little vibration but a true shake. It feels like the source is the front end but, at peak the whole truck shakes. At higher speed (48-55) the shake goes away. Tires and wheels are school bus take offs in nice condition. Any ideas on how to correct this? Many Thanks!

 

[Blue Goose]

The first thing I would check is how true the tires/wheels are running. With Dayton's, it's pretty easy to tighten them where they have the wobbles. Jack the truck up one corner at a time and spin the wheel by hand. At the same time, check your tires for roundness/flat spots.

 

[m78]

I'd be questioning why they came off the school bus. Maybe for the same problem ?

 

[Evan's f250]

Like above, I'd turn them by hand and check em over. If they seem ok, I'd have the balance checked out.

 

[kiwi f150]

The first thing I would check is how true the tires/wheels are running. With Dayton's, it's pretty easy to tighten them where they have the wobbles. Jack the truck up one corner at a time and spin the wheel by hand. At the same time, check your tires for roundness/flat spots.

I used to run an old D series ford (english flat nose truck) which only ever saw occasional use ..... it was running 900/20s and sitting in the shed it would develop flat spots in the tyres that would take about 40 - 50 miles of highway driving to come right - tends to shake the poos out of you though and make it look like you're doing some kind of funky chicken dance in the cab too

 

[m78]

I used to run an old D series ford (english flat nose truck) which only ever saw occasional use ..... it was running 900/20s and sitting in the shed it would develop flat spots in the tyres that would take about 40 - 50 miles of highway driving to come right - tends to shake the poos out of you though and make it look like you're doing some kind of funky chicken dance in the cab too

Flat spots you can feel at all speeds. He feels it at 38-45 mph.

 

[kiwi f150]

Flat spots you can feel at all speeds. He feels it at 38-45 mph.

You're right Mark i didn't read the top post properly - went and looked it up and discovered this article which is pretty much what Brad said

http://www.schoolbusfleet.com/Chann...dustry-should-retire-Dayton-style-wheels.aspx


Unless the Dayton wheel's lugs are evenly tightened, the unit may not run "true," meaning that the front or rear wheels could wobble. This wobble not only reduces the performance of the vehicle, it may also lead other motorists to believe that the wheels are loose

 

[Chaser95]

Thanks for all the quick responses! I truly appreciate all the input. I will jack it up and roll to see what I can see. I think the Daytons, by design, could be a source of problems now that you mention it Blue Goose. Seems like I can never get the adjustable wheels on my Ford 4000 tractor perfectly round either! The bad news is because of harvest it will be a few weeks before I can get a good look at the problem but, I think I can live with it that long.

 

[Blue Goose]

A way to greatly reduce a flat spot slap would be to clock them (that is IF you have them) 180* off of one another (inside dual and outside dual).

 

[DNFXDLI]

You might want to check the shocks as well, a loaded vehicle with shot shocks can set up a harmonic at certain speeds.