Back end hopping after new Coils and Shocks

[Stinkfist]

I bought a 72 longbox off of a kid this winter. He chopped it too low for my taste. Lowered via cut coils with the original 72 shocks. (shocks were just for show It was a definate hack job, but since this is my first old truck I'm not sure what else he screwed with.

Purchased some ST 2/3 drop springs and some cheap stock shocks just to get it on the road. Ride height is perfect for me, but now the back end hops on any bumps in the road. It takes about three or four bounces before leveling out. With any load in the box, it will bottom out two of the four hops.

If I push the box down in the middle of the endgate, the shocks seem to respond as expected. Any force down on either corner of the box makes the truck rock side-to-side like crazy. Stepping into the box feels like getting into a boat.

Any ideas on what I should do? I've read that you can flip the shock mounts to use the stock sized shocks, but most only do that with a 4" drop. Better shocks? I thought the cheap ones would at least make it drivable. Upgrade swaybars from 73-80? Can the control arms condition make any difference?

Thanks for any help you can provide.

[greasemonkey]

It sounds like you are missing the track bar that keeps the rear end centered on a coil sprung truck. If the PO lowered it too much the stock one probably didn't fit and he left it off.

[PICKMUP]

Try some good quality firm shocks to slow down the rear travel.

[cdowns]

good shocks (kby gas) sway bar new bushings in trailing arms and panhard bar all will help

[jhow66]

Sounds to me like your shocks are bottoming out.

[Hotrod70C10]

I'm with greasemonkey on this one.. sounds like the track bar isn't on the truck... other than that.. i would say pick up some stiffer shocks..

[Longhorn Man]

I dunno about this track bar (panhard bar) idea, I've driven one for a month with a broken panhard bar, and hopping wasn't an issue. This sucker would squirm or float over the body like mad, I only felt comefortable doping 40 MPH or less.
Look under the truck, and see what angle the shicks are at. They are supposed to look like this;
}-l--o--l-{
or maybe a slight angle like this;
}--/--o--\--{
(as viewed from the rear)

if the angle is more, to where the shocks are closer to horizontal than verticle, then they aren't doing a single thing.

Now if we are talking wheel hop... as in bouncing when you take off har, spinning the tires, then you probably have worn bushings in the trailing arms, if not rusted/damaged/falling apart trailing arms. Or worse, the shuddering could be clutch or converter chatter, making it seem like it is all in the rear end.

[76bonanza]

So longhorn man what speed do you normally dope at?

[Hotrod70C10]

I'm not sure about it being a problem with the shock angle.. If the shocks were laid over too far then you would have a really harsh ride... that is if the shocks are laying over enough to make them bind up.

[Longhorn Man]

Good eye!

[Stinkfist]

Thanks for tips guys. I'll check out the track bar... then maybe stiffer shocks. I'll post the results later.

[Robznob11]

well they say if you lower these trucks you should get a lowered shock kit witch helps withe the bottoming out issue and also relocates the top of you shocks for the proper angle. if your going to do it do it right you can get a kit from early classic or other places. also depending on the amount of drop even if you put a track bar on the should it be missing, if it is no in the proper geometry with the suspensing it will hurt rather than help. if you would like to try to cheap out however i have a track bar ill let go cheap.. i still think you would be better with a kit becuase stock shocks are made for stock higth and lowerd shockes are taylored to the smaller travel circumstances..just my .02 your not gonna be happy till its right. so do it right the first time and don't spen extra money trying to save a dime....

[ThatOneBlue67]

Rob has a point, I think you're supposed to buy the customized shocks that go with the shorter coils. That way they're "in tune" with each other.