Rear Suspension Rebuild

1980-1986 Datsun 720 forums. All 720-specific topics and discussion can be found here.
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PEZi
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Sorry for the lack of pictures, I'll try to explain the process enough to make up for it! If I miss something or if you have questions, ask away!

For starters...

Loosen lug nuts, jack the truck up, support the frame on jack stands and remove wheels. It is very helpful if you have a second set of stands, to support the axle with them.

Moving Forward...

1). Start taking apart the suspension. This is best done by first removing the u-bolts. To do this, loosen the 4 bolts holding them on.

2). Move on to the front eyelet for the leaf spring. Seen in this picture, it is held in by 2 bolts, one 17mm and one 12mm. (It may take some work to make the leaf drop down once this is removed due to age reasons like rust).

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3). Head to the back. As seen in this picture, the rear is attached via this shackle, with bolts also removable with a 17mm socket. Once the bolts are undone, the leaf will be able to be slid off of the shackle and removed from the truck. Repeat for both sides.

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4). Removing the bushings. The process is simple, but takes some ingenuity depending on age. The bushings will slide out, but to to age, rust etc. you may need to pound them out with your choice of weapon.

5). Compare old with new! Its just a fun step in the process... I chose Energy Suspension Red bushings.

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6). Now is the time to decide if you will be replacing leafs, or simply tidy them up a bit. Mine were in good condition, so all I did was take all my parts and prep them for paint. I also got new shackles, the eyelet and a leaf helper. I painted them using VHT Epoxy Paint in Satin Black to match the truck. It is water, salt and rust proof to preserve your investment ;)

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The Re-installation...

Once you have gotten all your parts back together, its time to put the new bushings into place. This is also a simple process, as the new ones slide right in...

1). Grab the new bushing and apply grease (pre-lube).

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2). Slide 'em into place!

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3). This goes for all the bushings...

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4). Once all the bushings are in, lube up the shafts on the shackles as well, and start by sliding the shackle into the bushing attached to the frame.

5). Slide the rear of the leaf onto its location on the shackle, and the bolt it all into place.

6). Next up is the front of the leaf, simply the reverse of the removal process.

7). PAUSE! You may have noticed we never removed the strut. If you are changing out struts, now is the time to do that. It is still attached to the frame via an 18mm nut. You will be removing the strut at this point regardless in order to simplify the rebuild process, but if using the old one, there is no need to remove it from the plate at the bottom!

8). Remove the strut from the frame location.

9). Re-install the u-bolts through the holding plate, and tighten. Make sure everything is lined up properly!

10). Once the suspension is re-attached to the axle, the strut can be remounted to the frame. The axle may need to be jacked up a little to allow the mount to line up.

11). Do a final bolt check, re-attach wheels and let the truck back down!

DONE!


synack7350
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are those new shackles then? if so I'm assuming energy suspensions does a whole kit? finally where'd you order the energy suspensions stuff from, or are you getting a deal on that stuff too? I like there stuff I used em to do my sway bar. Couldn't fine strut rod bushings from them though. ended up getting some oem replacements for like 10bucks from summit. If I can find the rubber I'll do this job when I get my shocks. when with pro comp toxics. summit they are like 37 a shock.

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PEZi
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The bushings are available from Energy Suspension. They make almost every bushing needed for these trucks (in fact, I think they make all of them). Just check their website! The shackles are OEM from the dealer.

synack7350
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have you / are you going to replace the body rubber? mine doesn't look to bad but, was thinking about doing it when I get to the body work this summer

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PEZi
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Haven't done it yet. Won't be until I get around to the "big stuff" where I'll be removing the whole body.

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fastboatman29212
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Pezi,
This is great stuff! You know that I like this kind of info since it can be used in the future for reference for DIY and repair problems! Keep up the good work and show us more!

synack7350
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man kind of off topic but I can't find where it was mentioned before and while we are talking rubber. do any of yall know how many threads are supposed to show after installing new strut rod bushings? (some call them compression rods)

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PEZi
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Not really, 'cause all brands will be slightly different. Mine are simply fully tightened down to where the threading ends.

synack7350
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ok thanks I'm just gonna crank the crap out of them then.

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Rev_D21
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Pezi, great to see you did this upgrade but why did you go with red bushings? Those don't have graphite impregnation like the block ones. Any reason? I'm just curious.

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PEZi
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Eh, kinda just didn't see the need. They make lube for a reason ;)

That... and I just don't really care if it squeaks.

synack7350
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I was thinking about the rear end a bit, you're always going to have a bunch of sway back there, its the nature of the spring, straight axle rear suspension. is there no such thing as rear sway bars for this type of set up?

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PEZi
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There are, but I didn't personally want to go with one. I upped the spring rate a bit using an adjustable leaf helper to reduce understeer in corners, same thing a bar would do. The difference, is that a sway bar allows for wheel lift under hard cornering, making the inside wheel 100% useless once you get to pulling hard G-forces. When that happens, you get no acceleration out of corners which is especially bad when you don't make much power to begin with. If I were to be drifting, I'd for sure go with a bar.

Adjustable spring rate leaf helper shown here :)

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