Many people tend to be curious as to the lowering of their pickups when they get them. This is the simple process to lower a Nissan or Datsun truck. It covers models all the way from back in the Datsun days through the hardbody days. The process uses lowering blocks in the rear and adjusting the torsion bars in the front.
Skill Level: 2 of 5
Time Required: 1 to 3 hours depending on your skill.
Tools Required: You will only need a socket wrench and an open end wrench. The size socket and open end will likely depend on the year your truck was produced so it is best to check what size you will need before starting.
You will need a set of lowering blocks which can be found at many local parts stores such as checker. You simply go up to an employee and tell them what you’re looking for as they are typically in the back. They come generally in 2″ 2.5″ and 3″ blocks and will lower the truck accordingly. Longer u-bolts will also be needed; your best bet is to take the old ones off once you get going to check out the size as different model pickups may have different sizes. The length will need to be extended in respect to the size block you purchase. New nuts and washers are typically included with the u-bolts. Lastly you will need new “drop shocks”. These are shocks specifically made for the change in ride height that your block is giving you.
For the front, of earlier model Datsun truck you may also need longer bolts in place of the stock torsion bar anchors as well. Make sure these bolts are grade 8!!!!
I. With wheel chucks around your front tires jack up the rear and put jackstands under the vehicle. Once the truck is up, release the jack so the springs will drop to full extension, but once full extension is reached use the jack as support for the axle while working.
II. Unbolt all four nuts from the u-bolts (see pic 1). The typical socket size is a 19mm deep dish though it should always be checked as your truck may be different. Also unbolt both the top and bottom bolts of the shock and remove it. The top is typically 18mm and the bottom a 16mm. Once the shock is removed, the u-bolts can be removed from the lower plate and the whole assembly can be removed from the axle.
III. Repeat on other side of the truck.
IV. Jack the axle back up as to separate the axle from the leaf springs.
V. Slide the lowering block into place in between the axle and leaf springs. There is a tab on the block and that will face down into a hole in the leaf spring. The stock tab on the axle will fit into a hole found on the opposite side of the tab on the block.
VI. Repeat on the other side of the truck. A partner may be helpful for this step as the other side may be unseated while putting in the second side’s block. The bet way is for one person to set in the blocks and then align the axle while a second person then lowers the jack back to full extension. Leave jack under for support.
VII. Put the new u-bolts around the axle.
VIII. Reattach the lower plate and torque the new nuts to the u-bolts at 75-85 ft lbs. Re-torque after 100 miles!
IX. Repeat on other side.
X. Reattach new shocks. Attach the lower end of the new shocks in to both sides. You may need to jack the axle up a couple inches in order to attach the tops of the shocks. Once attached and everything is tight, remove the jack stands and lower the truck.
Here is a picture of the leaf springs with the blocks, and new shocks installed.
I. With the e-brake on and wheel chucks around rear tires, jack the front end of the truck up and put it on jack stands.
II. Proceed to the torsion bar anchor bolts which are shown in picture 2. If you are having trouble finding them refer to picture 3. Picture 3 shows the path the torsion bar takes back to the anchor bolts from the front suspension.
III. Put your socket wrench (typically 17mm) on the bolt itself and the open end wrench (typically 15mm) on the nut on top of the bolt.
IV. Turn the bolt left (loosen) to lower the front end. You will need to choose your own ride height when doing this as there is not a 1:1 ratio for bolt movement to lowering height. This means you may end up jacking the truck up and down several times before you get it completely right. Each time you should let the shocks settle before measuring height. With older model trucks keep in mind you may need longer bolts to achieve your desired drop.
V. Remove jack stands and drop the truck.
VI. Go get a front end alignment because both your toe and camber will be out severely. You may find that if you have frame damage your camber may not be able to be fully readjusted due to the new drop.It took me about an hour by myself to lower the rear and you can bet on about 5 minutes for the front if you get the ride height right the first try… otherwise jacking up again and so on will take a bit longer.
Here is a picture of the torsion bar adjustment bolts, notice the clean areas showing where the bolts were adjusted.
Here is a shot of the torsion bar itself, where it connects to the control arm.
This is what the truck will look like once finished. It could be slightly higher/lower depending on what size blocks you use.
This article was written by Anthony Perez (PEZi303)