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This is a general guideline on how to approach changing out your leaf springs on a 1st gen Frontier. Mine is a 1999 V6 4x4 with the manual transmission, so that's what's in the picture. If you can open the pic, download it, whatever you have to do to make it bigger I have put several annotations on it that are color coded to help you understand where some of the more important bits are. I'm doing this write-up because of the severe lack of these tips in videos off of YouTube, which made this job take me an afternoon and well into the night to complete. I hope reading this will help you save time and as many headaches as possible.

First off, before you even start jacking the truck up you need to pick up at least 12 replacement 1/2" lock washers. I picked mine up at Home Depot, and considering where they are on the truck I would splurge for some that aren't supposed to corrode. These will be used on the U-bolt nuts as well as the rear shackles. These really should be replaced while you have them out, and a few of mine actually bent open while I was removing them, so I had no choice.

Next, you should hit all the nuts with your favorite penetrating oil the night before once you know your done driving the truck until your done with the leaf's. This helps immensely and should not be overlooked. I priced all the replacement hardware from a Nissan Dealership as well as Nissan Parts Deal (not much of a difference after shipping costs), and its close to $80 [at the time of this writing] in nuts and bolts to replace everything that were dealing with (minus the actual leaf's of course) so we want our OEMs to come out easy and go back on with as little trouble as possible. On the eye bolts (big bolts that are holding the leaf on and are the part of the spring closest to the engine), hit the nut on the inside of the frame with penetrating fluid not the head of the bolt that you can see if you just bend down and look at it.

SAFETY! It cannot be overstated, this can be a Dangerous job if you don't treat it with respect. Jackstands, quality floor jack for the differential, and chocking the front tires are all a must for this job. The shocks and the springs are really the only sturdy parts holding the rear axle to the truck and we will be removing them AT THE SAME TIME, do NOT put your leg(s) underneath the axle or brake assembly's at any time once the leaf is free and ask yourself - do I REALLY trust this floor jack with my life? I put my jackstands symmetrically underneath the part of the frame that sticks down further than the rest of the frame so that way I didn't have to have them extended any further than was necessary.

You should really consider changing out the shocks while your doing this job since your going to be right there with them and your going to have to remove, at minimum, the lower retaining nut for the rear shocks as this is part of the U-bolt base that needs to come out to get the spring out anyway. The front shocks on a 4x4 are stupid easy (not within the scope of this write-up), so if your willing to attempt changing out your own leaf springs you should most definitely consider changing out your shocks.

If you still have a spare tire hanging under the bed, go ahead and drop it down and out of the way BEFORE you start jacking up the truck. I found out the hard way that Nissan only put the exact amount of length in the chain to get the tire down while its sitting more or less level. It may be possible to change out just the leaf's without removing the spare, but since your probably going to be swapping out shocks while your down there having the spare out of the way is really helpful.

Only work on one side at a time! You should remove both rear tires once you have the truck jacked up, but only remove suspension hardware from one side at a time. This prevents you from getting in over your head as well as being able to go over to the other side if you suddenly have a question about how something is supposed to be or where it goes.

I don't know what the module is or what it does, but the square thing sitting directly on the top center of the leaf spring is attached to the rest of the truck with hoses or wires, making full removal of it problematic. If you know what it is and how to remove it, I definitely suggest doing so. It doesn't actually have to be removed, however, as you should have just enough play in the module to be able to suspend it with string from the frame. Going this route makes removing and replacing the leaf spring a bit of a puzzle game and this is the one part of the whole job where having a friend could be very helpful.

The order in which you should remove hardware after jacking up the rear end and taking the tires off is rear shock, the 4 U-bolt nuts on the underside of the steel plate the rear shock is attached to, then pull the U-bolts out, back the nuts off the shackle (rear most part of the leaf) but the shackle may not want to come out until you lower the axle, then lower the axle via the floor jack under the center of the diff just enough that you can see the leaf start to come off the axle, you should be able to remove the shackle now, and then break the torque on the eye bolt. The eye bolt should be last because pushing the bolt out while the spring is under tension could prove to be difficult, dangerous, and you run the risk of stripping the fine threads on the bolt. After the eye bolt has been removed, there should be nothing else holding the leaf in place but gravity, so figure out how your going to deal with the module on top of the leaf and finagle the spring out towards the rear of the truck.

On the passenger side, the eye bolt nut is shrouded inside of a "cubby" for lack of a better word, and a 7/8 wrench fit nicely on the nut. I used more string to hold the wrench in place while I loosened it at the head of the bolt. The eye bolt is almost $10 by itself through a Nissan dealership, if they have it in stock. Mine did not have any thread locker compound on it and it held torque for 16 years, but if you want to add some blue thread locker, you do you. I would NOT use RED thread locker or JB weld as this will probably make removing the eye bolt again in the future a truly aggravating experience (just watch a few vids on guys trying to change out leaf springs on old Jeeps and see how much they struggle with factory red thread locker). The driver's side eye bolt nut is not shrouded and removing it should be much easier (again, string on the wrench on the nut, break torque via the head of the bolt).

Once you have the old spring out you should lay it down next to it's replacement to verify that you do indeed have the correct spring and you can gauge how bent your original one is (makes you feel good about doing this in the first place). Before you move over to the other side you need to install the new spring on the side you've been working on, and other than the eye bolt nut shroud there is no difference in how you will change out the two sides.

Installation should be as follows, slip the new leaf spring in from rear to front (under the module if you didn't remove it, go slow and you will prob have to twist the spring around at least once to get it all the way in under the module). Next, push the front of the leaf (has a bushing and the hole the eye bolt will go through) up into its position where the eye bolt came out of and run the eye bolt all the way through, then hand tighten the nut on the other end. This will protect exposed threads and you will torque everything down at the end. What you may or may not have noticed is that when you removed the spring from the axle is that the axle may have shifted rearward once the leaf center pin cleared its corresponding hole on the top of the axle. If this happened, once you get to this point in the installation you may notice that the new leaf spring's center pin is not lining up with the axle hole. Stay Calm. This is normal, there is prob nothing wrong with your new spring, as long as its a quality replacement. What has most likely happened is that the axle shifted after you removed the spring. Remember earlier when I said that the shock and the spring are the only sturdy parts holding the axle on? Well, we just removed them so its not unlikely that the axle may have shifted. Simply attach a ratchet strap from a frame hole to the axle and slowly crank the ratchet until it pulls the axle forward enough for the center pin to fall in. Don't try to remove the eye bolt and then put the leaf center pin in the axle, this makes installing the eye bolt afterwards a real pain in the you know what. Once you have the leaf center pin in its hole on the axle you should be able to attach the shackle. If you forgot how it goes back together simply look at the other side, but remember your looking at a mirror image. Hand tighten these nuts with new lock washers and now you can remove the string holding the module up (or re-install it) we no longer need it dangling above the spring. Make sure that its sitting all the way down on the spring as Nissan has only given us the exact amount of threads on the U-bolts to get them on with everything else exactly where its supposed to be. Slide the U-bolts down from the top of the module and note how they have little lips they sit in on the module, they have to be fully seated here.

Now this part could take a while so be prepared to get frustrated at this point and take frequent breaks. You now have to get the steel base plate with the lower shock mount back in place with all four of the U-bolt threaded portions sticking through enough to get a lock washer and a nut back onto all of them. I noticed on mine that the U-bolts were bent differently from each other and they only wanted to go back around the spring a certain way. So if your having a hard time getting the U-bolts to go into the steel base plate try turning them or swapping which one is towards the engine and which one is towards the bumper. Again, hand tighten at first just to make sure everything is going back the way it was. Once you feel that there's no play around where the spring meets the axle, you can start to tighten everything with tools, but hold off torquing anything down until the end. You can re-attach the shock now or after you've finished with the other side, JUST DON'T FORGET TO INSTALL THE SHOCKS BEFORE YOU DRIVE!

Once you have one side done, leave the tire off and knock out the other side. It will be a mirror image of the side you just got done working on with the only other difference being the cubby for the eye bolt on the passenger side. Once I had both sides put back together with new springs and shocks I put everything to about half the required torque setting, then put the tires back on (knocked out a tire rotation while I was doing this since I had the front tires off changing the front shocks anyway) and then finished torquing everything while the truck sat on its own wheels. This is for safety and also the suspension should be under its normal weight to torque properly. You can either find the torque specs for your exact year and model of Frontier here on this forum or in the Haynes manual (which sucks for the 1st gen Fronty's IMHO). This is the most physically challenging part of the whole build because it will seem like those U-bolt nuts will never hit torque, but they will and by this point you've saved yourself hundreds, possibly over a grand depending, so let those dollar signs give you the motivation to finish strong. Some people have said in some of the videos that are out there on changing leaf springs that you should tighten and torque the U-bolt nuts in a cris-cross pattern. I followed this guidance myself, but I'm not 100% sure on how important this may or may not actually be. Lastly, its good practice to get back underneath it and check the torque on the eye bolts, the U-bolt nuts, and the shackle nuts after about 500 miles or so. The suspension shakes and rattles alot, and even though we have lock washers on everything but the eye bolts, it doesn't hurt to check!

I commend you for making it all the way through this extensive write-up! As you can see, this job isn't so much technically difficult as much as it is physically demanding. I was able to do this job start to finish, by myself, and I am in no way a body builder, a professional mechanic, nor do I consider myself "strong." Give yourself an entire weekend, have a driveable car on hand for the inevitable trip to a store, and having a friend to help will make this job much easier. Use this guide to help cover the more "Fronty specific" parts of the process but this guide is intended to supplement the general leaf spring replacement videos already on YouTube.

Thanks everyone, and work safe!
 

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Dude!

That is a first class write up...

You just saved me Hundreds of $...

Love the image with the annotations, I know how much time that all takes and I much appreciate it :thumb:
 
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