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Lowering Rear End


rstclark

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OK    I did the search but didn't find the answer

 

I have a 74 base model with spacers under the front, and it sits about one finger above the tire   The front is fine , but the back sits about 1 inch too high.  No offence, but the car sits on historically what was called a Dago -- back high  front low.  I'm good with the front     just want to lower the rear.  BTW rears have KYB gas shocks that are pretty firm but I don't think the shocks are jacking up the rear  

 

I'm ready to cut the rear stock springs  --  but the question is:  HOW MUCH DO I CUT TO GET 1 INCH of DROP    ie. 1/4 coil  1/2 coil 1 coil  ?? 

Please don't tell me to buy new  H&R springs Brillstein HD shocks and struts and maybe sway bars.  Done that before and it's wonderful, but this car is not worth all of that expense at this point.  Just need spring cutting advise.

 

Thanks

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What your asking is impossible to answer with any degree of certainty.  It is a moving target, that is why you couldn't find an "answer".

 

Consider this, there were multiple stock spring rates available when new, there were three different height spring pads when new.  Now understand that those springs, if original, have seen fourty years of use (and of course the no two cars have been driven the same).  I have seen "lowering springs" actually raise a number of cars whose stock springs had sagged so far.  

 

--------------------

Get in there and cut a little bit at a time, but be warned, drive the car for at least a day or two before making additional cuts.

 

Good luck and go for it.

Edited by AceAndrew
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Easier way...check the rubber spacers atop each rear spring.  They came in three different thicknesses, denoted by one, two or 3 dimples in the rubber.  AFAIK they're all still available.  US spec cars had 3 dot spacers due to the spacers inserted in the front suspension to meet Federal bumper height requirements.  You can drop the rear nearly an inch by going to one dot spacers in the rear, and they're easy to swap out.  Check archives for how to do it.

 

cheers

mike

'69 Nevada sunroof-Wolfgang-bought new
'73 Sahara sunroof-Ludwig-since '78
'91 Brillantrot 318is sunroof-Georg Friederich 
Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette) & Kermit, the Bugeye Sprite

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This is a us spec car sold originally in Texas, so most likely it has the three dot spacers  Never heard this before.  What if you just took them out and put some plastic tubing or hose around the last coil on top ? 

 

I will also check the archives

 

Andrew  that's for your input.  Trial and error may be the way to go  I do have more springs

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And to avoid getting excessive camber and toe when lowering that rear end, flip the subframe mounts and fit offset diff mounts. That will raise the subframe in the car. A great way to skip installing camber and toe adjusters.

Massivescript_specs.jpg

Brake harder. Go faster.

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. Here is the update:  The car has two dot spacers and I have a pair of one dot spacers from a 72   Just don't think a one dot difference is going to do it,  so I'm going to start cutting the springs in 1/4 coil increments 

My  other car, a 75 sits just a touch to high in the rear  so I'm going to reserve the spring pads  for that car which already has 1 inch lowering springs. Don't know at this time if the 75 has three dot two dot or one dot spacers but I suspect they are at least two dot and I will be able to adjust down with the one dot or two dots. 

Thanks to everyone for your comments  Particularly Andrew and Mike

This forum rocks  I now know what to do to get the desired results on both cars

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Would it make sense to loosen/retighten the trailing arm pivot bolts with the weight of the car on the wheels. after cutting the springs?

     DISCLAIMER 

I now disagree with some of the timing advice I have given in the past.  I misinterpreted the distributor curves in the Blue Book. 

I've switched from using ported-vacuum to manifold, with better results. 

I apologize for spreading misinformation.  

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Nah, probably not, IF the thing was assembled correctly the first time....

... so... yeah...

 

 

Do keep in mind that the rear spring's at about a .68:1 ratio with the rear wheel.

So for every .68" you shorten the spring, the wheel will drop an inch.

That's why the spring pads make such a difference.  You wouldn't think they would...

 

Cutting springs is a pain, because the part of the tail that touches the pad is not in 100%

load.  So as you remove, say, a 1/4 turn, you're not removing a quarter of a coil space.  AND the

tails are tapered, so at first you're removing very little height.  Then, as the taper goes away, you start

to get to where it IS making a difference-

but now, you don't have the taper to seat the spring, so it starts to bend from the columnar, and that

has a different rate than straight compression.  Add to the difficulty that the movement rate at the front of the spring

column is noticably lower than the rate at the rear of the column, the spring gains stiffness as you remove coils, AND the

spring can now rotate in the holders, and pretty soon the whole thing starts to lose the level of scientific control you might like when

you're just 'lowering it a bit'.

Or, conversely, when you really want to know exactly what's in there so you can make a small, controlled change.

 

One real reason I went to rear coilovers on the race car.  And went nuts with the E30, where we couldn't go to coilovers....

 

 

t

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"I learn best through painful, expensive experience, so I feel like I've gotten my money's worth." MattL

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