Rear end of truck slams hard on bumps with new billes 5160

I just installed a set of new rear billstien 5160 shocks and went for a test run, I went over a speed bump and the rear end slammed pretty hard I was wondering if it would be that the rear leafs are worn out or the shocks don't work? (Will install a set of 5100s in the front tommrrow )

 

Sounds like they are not long enough. This happened to me when I put on my Donahoes years ago.

 

did it slam on compression or extension?

if compression did you get the extended shock length? if so thats probably why.

 

It slammed on compression and I got the stock hieght shock

 

They were the same size as the stock shocks

 

Do you still have the bump stops in ?

 

Yup I still have the stock bump stops

 

That makes no sense to me. I know its not the collapse length because these actaully collapse a hair more than the 5100 do (5160 = 13.84" & 5100 = 14.02" collapsed)

Sounds like maybe something is wrong internally. I thought the valving is the same as the 5100s so there should be no difference on compression.

You happen to buy these used?

If new I would contact the comp you bought them from and discuss the situation.

You can always do a side by side.... manually compress both to see how they differ on compression.

 

I was looking under the. Truck and used a little black rubber seal or something that moves on the shock rod and went over the same bump and it looks like the truck hits the bump stop before the shock reaches its full compression would it be the leaf springs in that case?

 

Jump up and down in your bed. Is it soft? Can you hear the shock compressing? If all you get is a thud or travel fast and limited you have a bad shock, the wrong shock, or your leafs are crap and banging the bump stop.

 

I think my leafs are crap would you guys know a good leaf pack to put on and leave it at stock height and have a good ride