RSK issue with lift springs

97BambiBasherPSD · Aug 1, 2016

I'm using a PMF RSK kit with procomp SD lift springs. Well I go to put them in and the axle is shoved forward 1" and the shackle angle sucks! Measured the springs and they are 2" shorter than a factory spring. No idea if that's just cause they are a lift spring or not. I need to talk to Trevor and see if I installed the kit right. We tried flipping the springs around everything. Need some help!

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m_j · Aug 1, 2016

obviously those springs wont work. you would also benefit from a longer shackle with an arched spring.

Diesel_Brad · Aug 1, 2016

Here is the problem.

Stupid Dutys are Fat Pigs

On Average they weigh 1000lbs more than the equivalent OBS.

That is why one of the best SD springs for an OBS is the U or D codes since they are a softer spring

So you OBS does Not weight enough to squish the lift springs. Especially if you got them for a diesel truck. And with all the sheet metal missing off your truck, that doesnt help matter either.

Then after all that you will need to drive the truck to get the springs to settle in

97BambiBasherPSD · Aug 1, 2016

So brad your saying that once my ranch hand bumper and sheet metal are back on it should give me the correct alignment? I wanted lift springs on top of the 4.5 from the RSK. The 2" shorter leaf spring doesn't make a difference?

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Diesel_Brad · Aug 1, 2016

97BambiBasherPSD said:
So brad your saying that once my ranch hand bumper and sheet metal are back on it should give me the correct alignment? I wanted lift springs on top of the 4.5 from the RSK. The 2" shorter leaf spring doesn't make a difference?

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it is shorter because it is arched. Once you get some weight on it, it will flatten out and get longer......

but honestly, I still would of gotten gas lift springs

97BambiBasherPSD · Aug 1, 2016

Alright well I'll have to look into them then. Summit is pretty good about returning and getting the correct stuff

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97BambiBasherPSD · Aug 1, 2016

Just checked summit. The springs are procomp 22410s. It says for a 5.4-7.3 engine. 5.4s sit higher than a 7.3 with these springs.

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mikeeg02 · Aug 1, 2016

If you measure the length of the spring, you need to go from eye to eye, and the tape measure has to follow the arch. If you did it that way and it's still 2" shorter, it can't be the correct spring, or the rsk kit requires a specific spring. Regardless of any of that, a couple hundred more pounds will not fix your shackle issue. The only time it's acceptable for your shackle to look like that is at full extension. At this point you will have no downward suspension travel and quite honestly I'd be afraid to drive it. The shackle could go either way. (Towards or away from the frame) Are you 100% certain your front brackets are in the correct spot? And hopefully you added some more bolts.

97BambiBasherPSD · Aug 1, 2016

mikeeg02 said:
If you measure the length of the spring, you need to go from eye to eye, and the tape measure has to follow the arch. If you did it that way and it's still 2" shorter, it can't be the correct spring, or the rsk kit requires a specific spring. Regardless of any of that, a couple hundred more pounds will not fix your shackle issue. The only time it's acceptable for your shackle to look like that is at full extension. At this point you will have no downward suspension travel and quite honestly I'd be afraid to drive it. The shackle could go either way. (Towards or away from the frame) are you 100%certain your front brackets are in the correct spot? and hopefully you added some more bolts.

It's still in the mock up stages. I aligned it right to the holes that lined up in the frame. I'll have to recheck but we followed the arch of the spring and measured it. Maybe the kit isn't made for a lift spring, Just stock springs.

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mikeeg02 · Aug 1, 2016

I found another thread with pictures, it has a more stock height spring. Shackle angle looks like yours in one picture, but flat in another.

http://www.powerstroke.org/forum/su...-precision-metal-fab-pmf-rsk-install-obs.html

I also see there are inside bolts and only looks like one on the outside like yours shows.

97BambiBasherPSD · Aug 1, 2016

Again I don't have all the bolts in due to being mocked up right now to make sure it's all gonna work.

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Diesel_Brad · Aug 1, 2016

Here is a pic of my truck(460 gas) with 4" Superlift OBS front springs w 2 leafs removed and ORUs 2.5" RSK, 6" Skyjacker OBS rear springs w fitted add-a-leaf. If you notice the shackle is almost perfectly vertical

Same truck but with PMFs 2.25" RSK and U codes and B codes
Shake is pretty much in the same vertical position(kind hard to see but it is)

Jonnydime · Aug 1, 2016

Your springs are backwards compared to the pictures from .org.

mikeeg02 · Aug 1, 2016

Is there any room to move your front hangar rearward? The front axle will move rear slightly when you put weight on it, because of the arch, but that shackle angle just wont work. Especially if the weight is on the axle like it looks in your pictures right now. Have you tried moving the shackle with a pry bar?

There's always the slight chance the bushing on the shackle is compressed so much that it wont allow it to swing rearward. Maybe loosen that bolt so the shackle can swing, and see if it will settle into place, allowing the spring to extend (moving your axle rearward) and lowering the front some. Other than that, for that spring to work, you'll need to move the hangars.

97BambiBasherPSD · Aug 1, 2016

The reason for that is we wanted to make sure it wasn't a direction issue with the springs. The shackle angle never changed either way

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97BambiBasherPSD · Aug 1, 2016

There are only bolts in there. Nothing is tightened down. I can try the pry bar but I have a feeling it won't change.

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mikeeg02 · Aug 1, 2016

97BambiBasherPSD said:
The reason for that is we wanted to make sure it wasn't a direction issue with the springs. The shackle angle never changed either way

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The shackle angle wouldn't change by reversing the springs, the spring length is the same. The only difference could be axle location, if the leaf spring pin is not centered.

97BambiBasherPSD said:
There are only bolts in there. Nothing is tightened down. I can try the pry bar but I have a feeling it won't change.

If everything is loose, then your going to have to move the brackets. You can try putting your HD bumper on and seeing if it will settle some, and maybe a little more to simulate sheetmetal, but I think your hangars are going to have to move.

97BambiBasherPSD · Aug 1, 2016

It was just something we thought to try. They have since been changed back to the correct way.

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gnxtc2 · Aug 1, 2016

I think you have the wrong springs.

http://www.stengelbros.com/HeavyDutyLeafSprings.htm
Scroll down and check your measurements.

You want the military wrap up front. The theory behind the wrap is if the main leaf breaks, the military wrap suppose to keep the axle from being kicked out.

Billy T.
[email protected]

mikeeg02 · Aug 1, 2016

The link gnxtc2 provided shows that there is almost a 1" (5/8" to be exact) difference between the forward eye and the center pin, and the rearward eye and the center pin. Did you measure what they are on your set?

It says one eye to center pin 27 1/2", center pin to the other is 28 1/8". ~55 5/8" long. What are your measurements? Dont forget to have the tape follow the leaf spring.

I couldnt find specs on the pro comps.