The new rear spring saga...

So, I went to replace some dead rear springs on a Duster with a pair of the 002/003 SS springs. The hangers front & rear are an aftermarket 3/4" relocation kit. One might assume spring-eye locations would be same as OEM. Saw where the center-pin location on the shock plates had been moved forward about 1/2" by drilling a 2nd hole. Hmmm.
Well, with everything back together, the rear hangers refuse to go rearward past vertical, even with maybe 500 lbs of weight in the trunk; obviously binding the rear springs.
Looks like I need to whip up some 1/2" spacers for the rear hangers to move 'em forward so I can a proper angle: unless by some weird voodoo magic merely moving the shock plates corrects the rear hanger angle, but I don't see how it would. Seems that the dead springs masked the front eye location being too far forward.
Frankly, the 3/4" relocation doesn't appear to really buy any room at the spring/forward sidewall of the tire anyway, in case anyone reading this is thinking about doing that, but at least it makes fitting 2.5" tailpipes a tight proposition, haha.

002/003 should bolt on all 67 and later A bodies w/o re-work. Front segments on all S/S springs were 20", back segment was either 35 or 36 depending on application. If the springs were re-arched for some reason then sometimes you have to pry the shackle back as you lower the car - then after a while they take a set. Maybe post a pic?

Yup, not my 1st rodeo on SS springs; I've had a couple of sets on my Duster racecar & my early B-bodies. Like I thought I'd indicated, I think the issue is with the location of the front spring eyes due to the 3/4" relocation kit. The clue was the shock plates having been altered at the centering pin location.

I run SS springs on both my A-Body and E-Body. The springs bolted right in to the A-body, but I had used Dr Diff's inset hanger kit for the E-Body.

That E-Body kit also moves the front spring Eye mounting bolt reward just over an inch (guessing) and the rear shackles and spring locating pin line up like stock.

Dr Diff makes a 3/4" inset kit for the A-Bodies. It leads me to think you mounting bracket may be drilled incorrectly. A quick measurement and call to Dr Diff could verify that.

Another variation I have with these springs is that I run two passenger side SS springs on both cars so they sit level. I also run a lighter spring than they recommend for the street. They ride beautifully and the cars hook up harder that with any other suspension I've tried in 30+ years. Learned that trick from Dr Diff. I also run properly adjusted slapper bars on them.

JBC: yeah, that's what I'm thinking, but I don't have a stock Duster to measure. Rear wheels/tires sit about right in the wheel openings, though. The
shock plates being redrilled is kinda weird, since all it would reposition is the shock & U-bolts, not the axle.
Could be the springs just have too much arch right now and need to settle.

jbc426 sent you a IM

Got it, and replied.

Anyone know the dimension between the front face of the front spring-eye bracket (where it bolts to the chassis) and the center of the front spring-eye bolt? (Stock/original 70-72 Duster)
I need to know/confirm if the spring-eye location on these brackets is correct.
I'm gonna also measure the wheelbase & check driveshaft-yoke engagement.

1 and 3/4" 71 duster

Thanks, Danny.

jbc426,

What adjusted slapper bar are you using? Also, do you have any 60' times with & w/o the slapper bars? I have the same setup (i.e. 2x passenger-side SS leafs per Dr. Diff and you) on a Challenger and looking to improve 60' times.

I know they got a lot of bad press for not belonging on Mopars, but that is because a lot of people bolted them on straight out of the box, and they were not fitted properly. How many of you remember seeing cars driving around with these bars installed and a 3 or 4 inch gap between the rubber snubber and the bottom of the front spring eyelet? They don't do anything when mounted like that, hence the bad rep.

I buy the universal Lakewood sets from Summit and cut & weld them to fit properly. They need to be up tight against the bottom of the spring for max clearance and the rubber snubber needs to be just touching the bottom of the front spring eye. I also cut the rubber snubber in half to reduce deflection even more.

They are not designed or fitted specifically for Mopar out of the box. Because of the semi-elliptical design of our rear springs, they are actually perfectly suited to eliminate spring wrap and push the tires downward into the pavement upon acceleration. They function similarly to a pinion snubber, but without the harsh ride that the snubbers produce by stopping the rear suspension from compressing.

They do create significant torsional stress on the differential housing, but neither one of my cars have ever had any problems as a result.

They are inexpensive, easy to install, virtually eliminate spring wrap and my cars hook way harder with them on. I don't have any tracks near me, so no before and after time comparisons, but I can tell you once you try them, you will never take them off.

Got under the thing yesterday and the ft hanger measurement sure ain't 1.75", these are about 1.25" - but the wheelbase measured 108.5". The race-Duster has spring boxes (they're in 3") and it's cheated-up enough (being an old SS car) that it's not comparable to this car for this stuff.

Gonna double-check section lengths, trusting nothing, and go through it again. If someone could confirm what the stock measurement is, it would help.

I double checked mine, its 1.75, should mention it is a slant six car but wouldnt think it matters, looks to have never been apart

OK, thanks again, Danny. I don't think the S6 is different from the rest either.
I've always thought the Duster wheelbase was 108", was expecting this one with these brackets to be shorter, not longer than that.
Debating whether to space front or rear hangers to get the rear hangers at the correct angle; right now they're vertical if not slightly forward at the bottom, which binds the springs. It's mega-stiff right now & wants a ton of shim to get pinion angle down.