Technical Need advice on how to fix a bounce rear end

I know when I took the smallest leaf out that’s when my leaf pack started to be higher in the center than the eyes.

 

This is my leaf pack when I had them off before and painted them

 

I would try bolting a 1/4" X 1 1/2" flat bar across between the 2 shock mounts with new holes 1" and 2"further towards the middle for the shock stud. Moving the upper mount point in will increase the angle and make the shocks more compliant.

Gary

 

try turning springs over so smaller leaves are on top your impact from axle is wrong.

 

Don't do this ^^^^ . It has the same effect as removing all the leafs except the main leaf.
[Bad advice]

The OP needs to go through the process one at a time eliminating any bottoming out or binding [before he does the "dismantle of death"]

He should start by removing the leaf clamps/sliders , bump stops [or lowering blocks], and disconnecting the shocks to test it [do these one at a time] And drive it carefully around the block.

It has a lightweight rear end, that is probably bouncing on the tyres because the suspension cant absorb bumps.

 

Hey @Mimilan , hope you and your's are well.

 

All is good. Today [Monday] in NZ is a public holiday , so we're both taking the opportunity to be Lazy.

 

Good to hear.

I know you can help this guy out. He seems to be open to guidance.

 

He has the simplest suspension ever!
We just need to go through the process of fault finding [ the suspension is either bottoming, binding, or too stiff ]
Even though it is not ideal....the inverted leaf spring arch is not the problem [people are focusing too much on this]
The lowering blocks shouldn't be an issue unless they are placing the axle too close to the bump stops [which is easy to diagnose by removing the bump stops and trying it]

 

I looks close does that second leaf touch the spring eye? After seeing post 62 I can see that it dosen't

 

Good morning all, I just woke up so I’m going to drink so coffee and then head out in the garage to begin the investigation.

 

Part 1 of my investigation, I removed the leaf spring clamp bolts and took it for a short drive and the bouncing did improve by atleast 20%, didn’t seem as harsh, now I’m going to remove the shocks and see how it performs.

 

Removed the shocks and checked the amount of travel I have with them, 1. The angle of the shocks are at 30 degrees. 2. total length of the shock not compressed is 15in. 3. When mounted in the truck they are 12.5 inches and only have 2.5 inches of travel. I may have to move the top shock mounts to accommodate the full length of the shock

 

I have 1 inch of gap between the eye and leaf spring

 

Can't wait for the next instalment! Patiently waiting!

Chris

 

Just took it for drive with the shocks off and ride now is very soft and has a lot of up and down movement. When I go over rough roads it doesn’t feel like the wheels are coming off the ground and bouncing, feels more planted to the ground but a lot of up and down movement due to not having shocks in place to damper the suspension

 

Leaf springs are still higher in the center than the eyes, next step is take the leaf spring pack out and put the smallest one back in, this will have to be done tomorrow morning due to I have limited time today before I have to go to work, but I can tell I’m going in the right direction with what I need to do. I’m thinking that once I get the leaf spring back in I can take the top shock mount out and have new ones fabricated taller to work more with the shocks I have.

 

I think the root of the problem is the system (kit) wasn't designed for such a low stance. The springs were designed to use all their leaves, and you are trying to make it lower by taking them out. And, you are using huge lowering blocks to get it even lower.

That kit mounts the front of the springs down below the frame rails, where there is no way to get the truck really low. You could redesign the setup to move the springs inside the rails, setting them up higher in the frame to get your axle higher before you ever need to remove leaves or use blocks.

Some kits are built to do this already. But if you are a good fabricator you could modify your current parts. If you aren't (sounds like you aren't ready for this level of fab) I'd suggest buying a different kit or taking it to a good shop.

 

Looks like the shocks are gas ones. Maybe too stiff and you need hydraulic ones to soften the ride?

 

They could be but first I should probably put the leaf I took out previously to try to soften the suspension back in so my eyes aren’t below the center where it’s bolted down with Ubolts

 

Just watching, cuz I never worked on leaf springs. I'm not real familiar with the safety measures. Hopefully, you are. And I'm not quite sure how deep into this you're gonna go. But I've heard guys can get hurt. Just be careful with yourself.

 

Don’t worry, I’m taking plenty of safety precautions

 

In the 3rd picture, there looks to be some kind of round bar above the main leaf clamped to the front part of the spring. What does that do? BTW I had a C.E. parallel leaf kit (using their springs) and the springs were curved backward after the chassis settled and they rode and handled great for about 9 years. The rear shackles did angle to the rear IIRC.

 

Shortened version of the info on those shocks. You have 4.5 total inches of travel on the so at static height eye to eye centers should be right at 12.375 or 12-3/8. That is center of stud to center of stud at static rest height. The shock could be bottoming out when you hit a bump with that travel if you don't have it centered travel wise.

Brand:Monroe Shocks & Struts

Manufacturer's Part Number:33033

Part Type:Shocks and Struts


Summit Racing Part Number:MON-33033

Ride Height:Stock

Extended Length (in):14.625 in.

Collapsed Length (in):10.125 in.

The flat leaves don't give you any compression to speak of when you do hit a bump. they are going into an over loaded position as if you had a bunch of weight in the back.

 

Soft springs aren't the problem. Too stiff causes it to bounce!
Having the front eyes lower than the rear is a desirable quality for geometry.[have a look under any modern leaf spring car and you'll notice the rear eyes are higher than the front]

Normal gas shocks are no stiffer than normal hydraulic [except a bit of gas pressure that pushes the displacement of the shaft out]
If the stiffness [rating] of the shocks is too much! You can alter the motion ratio of the shocks by laying them over a few more degrees. [Early motocross bikes did this]

Before you rip in and pull the springs out. Could you do one thing!
Leave the shocks disconnected!
Measure the height of the fender lip to the ground [both sides]
Then jack the frame in the rear crossmember until the wheels are just off the ground.
And measure the height of the fender lip to the ground in the jacked up position.

[This will give you a rough estimate of spring load, before you rip in and dismantle the suspension]

That is not correct.
spring steel works in both directions.
As long as all the multi-leafs are on the compression side of the leaf and not the rebound side and the rating is the same.

Shape only alters the load height not the stiffness [so a height re-set spring and a flat spring have the same stiffness]

 

Not much happened today since it’s a tad bit cool and rainy in Ohio, but I did unbolt the axle and removed the leaf springs and did put the bottom leaf spring back in in both side and bolts the leaf springs back up. I checked the movement of the leafs with a floor jack just to make sure that my shackles weren’t binding up and the do move freely. Hopefully I can do more tomorrow

 

it appears there are some sort of clamps as mentioned on the forward portion of the spring--this will hinder spring action

 

Yes, there was, previous owner had those there, they are off now, I think they where there to tighten up the springs towards the front eyes.

 

Manufacturers use clamps that allow the leafs to slide. The clamps are only needed to keep the leaves together during spring wrap [or extreme "droop" with heavy unsprung weight]

If you have the springs out and apart. Paint strip and re-paint the leafs with Dacromet paint.
This is a controlled friction paint that trailer spring manifacturers use to allow them to slide.

Edit: If you cant get Dacromet, a couple of coats of zinc paint will suffice. [then assemble, and paint it black after assembled]