Leaf spring questions

[Madkaw]

I know nothing about leaf springs .  Though my truck is a 4x4 , it will be used mostly as a commuter and a truck. I look at my springs and wonder about the extra stuff on the ends . Seems like there is different gaps at the spring ends on either side of the truck. I have no history on this truck, but odometer says 160k. Is it time to replace ? Should I go with a progressive spring ? Any help? 

 

[datzenmike]

18 minutes ago, Madkaw said:

I know nothing about leaf springs .  

 

 

True.

 

Don't fix what isn't broken. You want to spend money, and improve the ride handling??? Replace the shocks.

[Madkaw]

Shocks are purchased . I thought I’d get some education from someone here on leaf springs , so I’d know if it’s broke or not. 

I thought this was the 720 forum? Maybe could attest to the expected life of these springs on these NISSAN trucks. I think I’m smart enough to know you don’t fix shit that’s not broke, but maybe there’s better options . 

Maybe some one on the 720 forum could have something to say about the ride quality since I specified it was going to be a commuter . 

Jesh

[G-Duax]

Besides new shocks, people make leaf spring lining material, that you put between the leafs, to make them slide against each other smoother.

Speedway Motors has it.

Of course it helps if you polish up the leafs them selves, and apply a good thick grease to the surfaces when you reassemble them.

 

Before going 4-link & coil-overs I used that stuff, and it made the truck ride smoother.

I used Bilstien shocks all around.

[Madkaw]

Let me add that I’ve never owned a 720, so have no relevance to work with. I could have googled leaf springs and learned a lot, but I doubt anything specific to 1983 720’s would be found in that reading 

[Madkaw]

1 minute ago, G-Duax said:

Besides new shocks, people make leaf spring lining material, that you put between the leafs, to make them slide against each other smoother.

Speedway Motors has it.

Of course it helps if you polish up the leafs them selves, and apply a good thick grease to the surfaces when you reassemble them.

 

Before going 4-link & coil-overs I used that stuff, and it made the truck ride smoother.

I used Bilstien shocks all around.

 

I thought about cleaning them up, but I wondered if it was worth it vs. replacing with new springs . Are the “turds” hanging at the end of the springs OEM and do they do much?

[Charlie69]

1 hour ago, Madkaw said:

I know nothing about leaf springs .  Though my truck is a 4x4 , it will be used mostly as a commuter and a truck. I look at my springs and wonder about the extra stuff on the ends . Seems like there is different gaps at the spring ends on either side of the truck. I have no history on this truck, but odometer says 160k. Is it time to replace ? Should I go with a progressive spring ? Any help? 

 

Looks pretty flat to me.  I bet you could sell the leaf springs to some one with a 2wd 620, 521, or 520 to help fund the replacement costs.

 

I have been told the weight looking things on the springs are for harmonics.  Keep the springs from singing to you!  LOL

Edited November 5, 2018 by Charlie69

[Madkaw]

Thanks Charlie, that helps. I don’t want to waste money on stuff I don’t need, but if the truck needs springs , I’ll get them . I want a nice riding truck . I’ve completely redone the front suspension - every piece. Time to pay attention to the rear. I planned new bushings and shocks, but the springs are $$ , so I want to know what to do here

[datzenmike]

These are 4x4 leaf springs, much stiffer than the 2wd ones. There will be small gaps to allow the top spring to flex freely and comfortable. As weight is added or the speed over a bump increases or the height of the bump increases, the gap closes as the truck comes down on the next leaf, then the next and so on. In this way the spring is relatively soft for comfort yet becomes progressively stiffer as it is needed for carrying a heavy load of if off road.

 

I've wondered what those hanging things are too. No idea.

[Madkaw]

2 minutes ago, datzenmike said:

These are 4x4 leaf springs, much stiffer than the 2wd ones. There will be small gaps to allow the top spring to flex freely and comfortable. As weight is added or the speed over a bump increases or the height of the bump increases, the gap closes as the truck comes down on the next leaf, then the next and so on. In this way the spring is relatively soft for comfort yet becomes progressively stiffer as it is needed for carrying a heavy load of if off road.

 

So someone could put 2WD springs on a 4WD if they wanted a softer ride? 

Im betting the ride height would be different and wouldn’t look right?

[datzenmike]

Yes the 2wd will fit. They have more arch but the 4x4 is slightly heavier and may cancel any height difference gain. You could also remove one of your leaves, like the one with the funny add- ons.  You would have to realize this is trial and error and you might not like it too soft or not enough. 

[Madkaw]

They would be a lot easier to clean up with that spring without the add-ons. 

Now im getting some ideas . I priced new springs at about 350$ for the pair -ouch.

 

[datzenmike]

The stiffness or spring constant for the 2wd spring is 54 pounds per in (lb./in.) the 4x4 is 77. 

[Madkaw]

I guess with torsion bars up front I can adjust to match the rear - whatever I do

[bottomwatcher]

My 82 doesn't have the "spring dingleberry's" But I did put an add a leaf in to give a 1 1/2"  lift to match the front 2 inch lift. Nearly 250k miles and springs seem fine. The biggest improvement and Mike will argue with this was adding polyurethane bushings. I was pulling boats frequently and would get the tailwagging the dog syndrome. The poly really keeps things in line, that was 150k miles ago and still seems fine.

[Madkaw]

I’m going poly on he rear. I did rubber up front

 

[datzenmike]

Rubber is more compliant, quieter and does not transmit vibration. Polly use does have advantages, but not for average driving.

[Madkaw]

Nissan no longer sells the rubber bushings for leaf springs , maybe someone else does

[G-Duax]

Try Energy Suspension, they had the 620 bushings, and they are probably the same.

Even if not, if they have them for the older truck, they probably have them for yours.

[Charlie69]

If you want rubber rear bushings I get them from NAPA.

[Madkaw]

12 hours ago, Madkaw said:

Nissan no longer sells the rubber bushings for leaf springs , maybe someone else does

 

I stand corrected, Nissan does sell them , and so does others . I already have some poly sets , are they really that bad for rear leaf springs ? 

[datzenmike]

They are not bad for springs. They can be good or bad depending on the driver preference. They are much harder so there is less 'give'. Under extreme (and I mean performance racing or driving) they more firmly connect the moving suspension parts and the car body. The down side is more noise and vibration. Rubber on the other hand grips both moving parts and will give or twist internally. Poly has a much harder time doing this and usually one side will slip and this leads to chaffing ( squeak) and wear. I had some poly on my leaf spring shackles and the holes were worn oval shape. I guess you could grease them. In most cases people don't drive to the limit where they would know the difference anyway and they are usually replacing severely worn out rubber parts. Naturally they would 'feel' a difference, but new rubber would have done the same thing. Race cars use poly because the disadvantages are irrelevant and they are replaced or maintained regularly. For everyday driving they are overkill.   

 

If replacing specially with rubber, always tighten with the vehicle sitting normally on it's wheels. 

[Madkaw]

Well I had already bought a poly kit , so that’s what’s going on. I did order new shackle pins because they were toast . They would have ate bushing quickly. 

I was told by a Nissan guru that the weights on the ends were mass dampers as Charlie eluded to. 

[bottomwatcher]

I will still call them "spring dingleberry's"

[Madkaw]