Removing leaf springs

[Justin Berni]

i might buy a 620, and if i do i wanna lower it for sure, and i was wondering, what all do i need to do for removing a leaf spring and how much lower will it be? and in the 620's, isnt the back leaf and the front a different type of suspension? 

[Dat Lurka]

Search bar, use it. 

[Tristin]

I would advise against making a bunch of threads for projects you might not even do... you dont even own the truck. Feel free to use the search bar or look around the threads on the site, but youre not even sure if youre getting the truck. If you were just waiting to pick it up, that would be one thing. 

 

If you actually buy the truck, then make a build thread and most of your questions and what-not will be answered in there. 

[datzenmike]

The back is leaf spring and the front it torsion bar.

 

 

 

Two things....

 

The rear end is held in place and prevented from moving side to side on corners by the support of the leaf stack. While one leaf may not affect it too much, too many removed and the spring becomes unstable and the entire axle can shift sideways on hard corners. Even an inch could chew the sidewalls off those expensive tires.

 

Removing a leaf will lower the spring rate. A lower spring rate (softer) will allow the suspension to travel farther when driving over a bump or dip in the road. Think about this. A lower truck that now sags lower on dips in the road. Seems to me that there is even more chance of bottoming out. If anything a lower truck should have a stiffer spring rate.

 

 

An easier method is to buy lowering blocks. They mount between the leaf springs and the axle. A 2" or maybe 3" drop will lower the back by that amount . Because the springs are not changed they remain the same stiffness.

[datsunaholic]

^^.

 

With lowered trucks you actually want a harder ride, to avoid bottoming.  So, one way is to use reverse-arched springs, such as 4X4 springs.  The other way, which is actually simpler, is use lowering blocks.  Spring rate and nominal load capacity is the same, though you'd bottom out easier with a load. 

 

Removing leafs is a surefire way to end up with alignment issues.  They may not crop up immediately, but eventually you WILL twist the main leaf if you remove more than half the leaves.  All it takes is one pothole while turning.  And this is Washington:  Land of potholes.  Sure, folks say they've gone monoleaf with "no issues" but they have to drive like pansies and the "truck"'s bed is now as useless as a Smart Car's trunk.

[Justin Berni]

i looked into the loweing blocks for the book and that seems fairly easy, but how hard/expensive will it be to do the front?

[datzenmike]

 

Cost? Nothing.

 

Raise front end. Loosen the top nut on each side loosen bottom nut upward and inch or so. Lower vehicle and check height. Adjust to suit yourself. Tighten top nut down on lower nut to hold adjustment.

 

Changing the ride height will always change the toe and camber setting on the front wheels. You may have to align the front end depending on how much you drop the front.

[pharouh]

Wow Mike,that picture looks familiar.   ;)

[datzenmike]

What can I say, (besides I didn't know) it's a perfect picture for showing what I mean.

[Justin Berni]

that helped alot! thanks! im getting my truck this weekend and by the end of the weekend it should be lowered a little in the front, not sure when ill do the back/.

[gearhead]

so what about about when the truck was owned by a construction companie that put overloads in the leaf spring AND put Coil Over overloads in there as well.My truck has a 1/2" thick flat overload,plus extra leafs,Plus a coil  spring overload as well.It rides like a tank.My back takes a beating driving it around.

[datzenmike]

Many 620 rear leaf springs had the 1/2" flat leaf, it probably came with it. Remove the coils springs and the back might lower by itself. How do you know there are extra leaves? Normal to have 5 or 6 I think.

[datsunaholic]

Depends on year and even then they can vary.

 

 

 

Above, That's stock for a '74; '73 is the same.

 

 

Below:  '76 with an added "helper" leaf:

 

 

But the rest of the spring pack is stock, including the tiny overload spring on the bottom that you can barely see.

 

The amazing thing is that the 3-pack springs are actually heavier than the 6-pack springs.  The 6 thinner springs are softer, though not with that massive add-on spring.  I had 1500lbs in that '74 and it only went halfway to the bump stops... and actually rode a lot smoother.  1000 lbs in my Mom's Ranger had it sitting on the bump stops.

[chrisb76]

Mine only has the 3 pack without the flat leaf it rides ok or did on 15'' wheels not so good on 20's.

[gearhead]

good lord that thing must be a slug with those 20's on there.I know those are way heavy,and have a huge moment of inertia compared to 15"