mnementh666 Posted April 7, 2008 Report Share Posted April 7, 2008 Anyone know offhand how many leaf springs in the factory packs? It's a '70 521, if that helps. I think the PO removed one or two. Rides a little soft... which might be ok normally, but when I actually use the truck, I worry about the ass-end bottoming out. :blink: Quote Link to comment
VRTSid Posted April 7, 2008 Report Share Posted April 7, 2008 Sorry I dont have an answer but SUB question, do 620/hardbody/other leaf swap in? Quote Link to comment
datzenmike Posted April 8, 2008 Report Share Posted April 8, 2008 If it helps... the 521, 620 and the 2 & 4 wd 720 rear springs are the same length 1,200mm or 47.25" for the Americans in the house. Measure the 521... bet they are the same. If it has the thick almost flat helper spring it will never bottom out. Quote Link to comment
pope_face Posted April 8, 2008 Report Share Posted April 8, 2008 Not exactly sure, but I think it was a three leaf plus overload pack... so the main spring, two middle ones, and the flat one on the bottom. Hey Mike, any idea on the relative height and stiffness of these packs? Assuming they're all the same length (and width), would installing a 4x4 720 leaf pack on a 521 result in a lift in the rear, or would a 521 leaf pack on a 620 offer a softer ride? Quote Link to comment
MrRobatoGato Posted April 8, 2008 Report Share Posted April 8, 2008 I counted four maybe five...don't know if the PO took any of the life springs out.. Quote Link to comment
datzenmike Posted April 8, 2008 Report Share Posted April 8, 2008 I can only compare a '78 with an '84 2 or 4 WD '78 620 Standard 47.25"L X 2.36"W X 0.28" Thick... Qty two 47.25"L X 2.36"W X 0.51" Thick... Qty one Free camber..... 6.34" Laden camber... -0.28" @ 308 lbs '84 720 USA Standard 47.25"L X 2.36"W X 0.28" Thick... Qty two 47.25"L X 2.36"W X 0.51" Thick... Qty one Free camber...... 6.34" Laden camber.... -.28" @ 992 lbs Optional 47.25"L X 2.36"W X 0.28" Thick... Qty one 47.25"L X 2.36"W X 0.31" Thick... Qty one 47.25"L X 2.36"W X 0.47" Thick... Qty two Free camber....... 5.20" Laden camber..... 0.20 @ 1,036 lbs 4WD 47.25"L X 2.36"W X 0.28" Thick... Qty one 47.25"L X 2.36"W X 0.31" Thick... Qty one 47.25"L X 2.36"W X 0.47" Thick... Qty one Free camber........ 3.685" Laden camber...... -1.22" 1,021 lbs Heavy Duty 47.25"L X 2.36"W X 0.31" Thick... Qty two 47.25"L X 2.36"W X 0.55" Thick... Qty two Free camber......... 4.51" Laden camber....... -.295" @ 1,532 lbs Does this make any sense????? I think Doug will tell you that the 520 or 521s had really stiff springs. My theory was they used the same ones that were used on the UK ones (one ton I think) and just rated them lower (on paper) for North Am. I loaded over 1,500 lbs in my old 521 and pushed the rims almost through the tires but sat not too bad and drove fine, slow on gravel road back to farm. Quote Link to comment
VRTSid Posted April 8, 2008 Report Share Posted April 8, 2008 this might be obvious but is that 47.25" measurement along the arc or bolt to bolt? Quote Link to comment
VRTSid Posted April 8, 2008 Report Share Posted April 8, 2008 hey mnementh666, I found some links you might be interested in http://www.springworks.com/coil-leaf/auto-leaf-nissan-truck-buy.html http://www.autopartswarehouse.com/search/?N=11399+1684+4294966707+7668 Quote Link to comment
pope_face Posted April 8, 2008 Report Share Posted April 8, 2008 Mike, that does make sense, thanks for the info. Now I just have to actually figure out how much of a difference it all makes. Strange how the '78 and the standard '84 seem to have identical spring measurments, yet the '78 is fully laden at 308 lbs, and the '84 is fully laden at 992 lbs... are you sure the numbers for the '78 are correct? By the looks of it you could do a fair bit of modification just by swapping the leaf packs... if you swapped out a set of soft leaf springs with a set of firmer ones with a couple leafs removed, would you be able to drop the truck but still keep the suspension firm, or would you have to do it the other way around? As in, soft springs in place of firm ones. Quote Link to comment
mnementh666 Posted April 9, 2008 Author Report Share Posted April 9, 2008 hey mnementh666, I found some links you might be interested in http://www.springworks.com/coil-leaf/auto-leaf-nissan-truck-buy.html http://www.autopartswarehouse.com/search/?N=11399+1684+4294966707+7668 Those are interesting, but I don't want to add height, just was feeling a little insecure about the capacity :blink: If the others will take a thousand lbs, I'm feeling at least a little better. I counted four leaf springs and the flat bar, so that's cool. Maybe one of the many coil "helper" springs will be in order someday, like when we move or something, but it should be ok for now. Thanks for the responses guys. Quote Link to comment
VRTSid Posted April 9, 2008 Report Share Posted April 9, 2008 the first link I think is just oem replacement springs what about just some helper springs? Quote Link to comment
datzenmike Posted April 9, 2008 Report Share Posted April 9, 2008 I can only compare a '78 with an '84 2 or 4 WD '78 620 Standard 47.25"L X 2.36"W X 0.28" Thick... Qty two 47.25"L X 2.36"W X 0.51" Thick... Qty one Free camber..... 6.34" Laden camber... -0.28" @ 992 lbs NOTE THIS HAS BEEN CHANGED!!!!!! '84 720 USA Standard 47.25"L X 2.36"W X 0.28" Thick... Qty two 47.25"L X 2.36"W X 0.51" Thick... Qty one Free camber...... 6.34" Laden camber.... -.28" @ 992 lbs Optional 47.25"L X 2.36"W X 0.28" Thick... Qty one 47.25"L X 2.36"W X 0.31" Thick... Qty one 47.25"L X 2.36"W X 0.47" Thick... Qty two Free camber....... 5.20" Laden camber..... 0.20 @ 1,036 lbs 4WD 47.25"L X 2.36"W X 0.28" Thick... Qty one 47.25"L X 2.36"W X 0.31" Thick... Qty one 47.25"L X 2.36"W X 0.47" Thick... Qty one Free camber........ 3.685" Laden camber...... -1.22" 1,021 lbs Heavy Duty 47.25"L X 2.36"W X 0.31" Thick... Qty two 47.25"L X 2.36"W X 0.55" Thick... Qty two Free camber......... 4.51" Laden camber....... -.295" @ 1,532 lbs Does this make any sense????? I think Doug will tell you that the 520 or 521s had really stiff springs. My theory was they used the same ones that were used on the UK ones (one ton I think) and just rated them lower (on paper) for North Am. I loaded over 1,500 lbs in my old 521 and pushed the rims almost through the tires but sat not too bad and drove fine, slow on gravel road back to farm. Thanks POPE I corrected it. I had some spring rate number from the line below. The '78 and '84 are the same. :o Quote Link to comment
ClarksvilleFJ60 Posted August 9, 2009 Report Share Posted August 9, 2009 "78 and 84 are the same" Does that mean I can put the rear springs of an 84 on my 78? I'm trying to lift it 2-3 inches. Thanks. Quote Link to comment
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