Need help with rear "bounce" problem please

[lincolnlocker]

Does anyone get it at faster speeds? Mine isn't just at one speed its more to do with a section of road vs speed

mine starts bad at 40 and will almost bounce my girls bokbies out of her braw.. it goes a way for a couple mph but it then just turns into a vibration but i believe i have something bent.. i have been to ford abouut it and they said tbey cNt find anything wrong.. i jacked up the rear of the truck and let it idle in first gear and you can see my left rear tire wobble so i then tore it down to the brake drum and everything still wobbles so its not my rims and tires.. i have a vid on you tube ill post.

live life full throttle

 

[Dzchey21]

you think its the flex playing a more prominent role ? I sure as hell am not scared to box the section that causes it.

i was watching a dually the other day coming home from denver and you can tell between the bed and the cab that its flexing somewhere in that area. I would imagine that a 4 foot box in the frame somewhere in the middle would help.

Only reason i watched the dually was because of the comments made here in another thread about shocks, its definatly the frame moving. I have noticed sometimes it will keep bouncing even when you hit a section of pavment after concrete for a little bit untill it settles.

 

[Stroghty]

I know there are some great shocks out there but for someone budget minded what would you recommend.. I would like to keep the price below 200 per shock... I read rancho rs9000xl are decent and about 100 per shock???

 

[neverkickn]

i was watching a dually the other day coming home from denver and you can tell between the bed and the cab that its flexing somewhere in that area. I would imagine that a 4 foot box in the frame somewhere in the middle would help.

Only reason i watched the dually was because of the comments made here in another thread about shocks, its definatly the frame moving. I have noticed sometimes it will keep bouncing even when you hit a section of pavment after concrete for a little bit untill it settles.

I am pretty sure that's what's going on with mine. I have 16k on a 14 cclb and it will bounce consistently at anything above 75 mph. It will also do it at other speeds depending on load and road conditions. I have balanced the tires with no change. It has done it since day one.

 

[strokinpower]

just tie the bottom of the frame rails together

 

[Dzchey21]

I am pretty sure that's what's going on with mine. I have 16k on a 14 cclb and it will bounce consistently at anything above 75 mph. It will also do it at other speeds depending on load and road conditions. I have balanced the tires with no change. It has done it since day one.

same with mine and as others have said 70-75 seams to be the most noticable 80 mph makes most of it go away. 40 mph if i hit a bump right will do it pretty bad as well.


If i have a trailer tho, no issues at all. I drove around the other day with 4 extra wheels and tires in the bed and it was smooth as glass so obviously weight helps. My dads truck only has 2 leafs in the rear and it drive much better but also squats alot worse with a trailer.

Thats why i agree that the suspension is playing a factor but i really doubt shocks make the biggest difference. I was talking to the glass guy the other day and he was telling me that the original superdutys broke windshields all the time because of the frame flex. the bounce going down the interstate mixed with a non isolated windshield mount would make them break and cause the really common half moon break at the bottom of the window. I always noticed the break but never knew why.

I think after i shorten the frame on this project truck of mine i am going to box in a good part of the frame and see what that does.

 

[Dzchey21]

There is a section of road in town thats pretty easy to make the truck bounce, maybe ill strap my go pro on under the truck and see if there is any way to view exactly what the frame is doing. Maybe we need to tie in the frame rails between the transfercase cross member and the rear driveshaft mount crossmember, or maybe it needs boxed in.

 

[WHY NOT]

You guys think it would be possible to make a bolt in boxed section that way it is still possible to get the fuel and electrical lines if need be. Otherwise just welding a piece under there couldn't be to bad. The biggest pain will be getting one between the frame and fuel tank

 

[WHY NOT]

I know there are some great shocks out there but for someone budget minded what would you recommend.. I would like to keep the price below 200 per shock... I read rancho rs9000xl are decent and about 100 per shock???

Fox 2.0's are a great shock for the money. Put them on my dads truck and it rode down the back roads quite a bit better

 

[smokinstroker]

Fox 2.0's are a great shock for the money. Put them on my dads truck and it rode down the back roads quite a bit better

Excellent shock choice for the money

 

[sledhead_24_7]

My 2015 has the shake at 45 mph real bad. Then smooths out till about 70 mph them there is a slight vibration. I am going to say the same as others it is a frame issue or combo of driveline and frame.

Totally sucks though.

 

[Platinum250Scorpion]

I remember one of my grandparents' 150s havin a box steel frame & Ford advertising it for a while. Um, soooo, why don't our much more hd trucks have that? Is there some logical reason behind it that I just don't know or is it simply because Ford wants it that way; maybe for a smoother ride? Just a thought I've been having while reading the posts in here.

- A vet' that's gone from a 7.3 to a 6.7, tryin to gather info & help out when I can. New to the 6.7 & PSA. Please excuse my potential FNG ways.

 

[MadDiesel73]

carli add-a-pack and 2 5/8 shocks fixed it for me butter smooth

 

[Stroghty]

carli add-a-pack and 2 5/8 shocks fixed it for me butter smooth

What are carli add a pack? Can you give me a link?


Ok ill look at the fox shocks... Can someone tell me which size I need as I want to add the 2.5" level kit and 3.75"rear block but may be a bit.

 

[bigrpowr]

You guys think it would be possible to make a bolt in boxed section that way it is still possible to get the fuel and electrical lines if need be. Otherwise just welding a piece under there couldn't be to bad. The biggest pain will be getting one between the frame and fuel tank

it would have to be , or not box but long straps of thick plate on top and bottom . something that wouldn't flex. I would prefer a bolt in box.

 

[WHY NOT]

Ill have to crawl under mine and take some measurements I guess and see If I can find a good place to put something and have the local welding shop bend something up

 

[Dzchey21]

On the straight sections you could basically double up the frame like they do on big over the road trucks basically better than boxing it in. I'll check it out on this 04 when I chop the frame up

 

[bigrpowr]

On the straight sections you could basically double up the frame like they do on big over the road trucks basically better than boxing it in. I'll check it out on this 04 when I chop the frame up

that's what I was thinking.

 

[strokinpower]

I would try tying the bottom of the frame together with a simple cross member first

 

[Sterling6.7]

Stupid question and maybe asked before - are the FX4 trucks experiencing this less, same or more than the others? Mine does not have the FX4 package, but I looked under a '14 today that is and it has the additional skid plate under the transfer case. It is still a little thin, but it may serve the purpose. Also, I am thinking about spending the $30 or $40 on just that plate and stiffening it up so that it will serve the purpose. Thoughts?