Buddy has a 72 Blazer he is redoing and recently bought a 4 inch lift from Rough Country, and got the rear spring option instead of blocks. After installing it on the chassis the rear sits way too high. He called them and they said its because its unloaded, so he put the body back on plus some weight and it still had a huge rake to the front. The other issue is that the rear driveshaft is about 3-4 inches from being long enough to get to the case. Also, the shims on the rear springs don't appear to be large enough to adjust the pinion angle towards the case. I'm thinking something is a foul with the springs. Has anyone ran into something like this with rough country springs before? Any ideas?

Prolly got shipped the 6" springs for the rear instead of the 4's. Cross the part number off the springs wit rough country.

That's what he thought at first too....he called them and gave them the number off it and they said it was right. I think he needs to request a different set of springs and try it maybe.

Most lift springs are the same for blazers, 1/2 and 3/4 ton trucks. Stock trucks always have a little rake to them so that when you load them up, they still sit level. Do the new springs have an overload that you could take out?

Yeah they have 5 leafs instead of the stock 4. This is the 5th 67-72 truck he has done and has never had this problem (hence why he called me lol)....he has always used a 4 inch lift and the stock driveshafts with no problem. The main difference is, he bought rear springs this time instead of blocks. The thing I don't agree with if they are indeed a 6" spring, the taper shim is still way too small to ever keep a U-joint in it.

they will settle after they are used for a bit.


you need to check the pinion angle with a angle finder to get the right shims for the rear, dont just throw some in there.

Yeah they have 5 leafs instead of the stock 4. This is the 5th 67-72 truck he has done and has never had this problem (hence why he called me lol)....he has always used a 4 inch lift and the stock driveshafts with no problem. The main difference is, he bought rear springs this time instead of blocks. The thing I don't agree with if they are indeed a 6" spring, the taper shim is still way too small to ever keep a U-joint in it.The reason why he hasn't had this problem before is because with a truck that old, you are probably getting6-7 inches of lift with a four inch spring. The stock springs have surely sagged a couple of inches in the last 38-43 years. A four inch lift spring is four inches over stock, not where it currently sits. That's the reason why a lot of trucks with blocks sit low in the rear. The front comes up six with new springs, but the rear only comes up four with the blocks.

As far as the shims, do it right and put new spring pads on at the correct orientation. it takes at most a couple of hours.

Nah I don't buy that at all...if you had to cut the perches off, no one would buy bolt on lift kits. Its not that he won't do that if he has to, its just stupid if something else is wrong.

They list different springs for a 52" or a 56"....whats a blazer spring?

Nah I don't buy that at all...if you had to cut the perches off, no one would buy bolt on lift kits. Its not that he won't do that if he has to, its just stupid if something else is wrong.You don't have to, but it is the right way to do it. Shims break if you wheel your truck hard, especially the shitty aluminum ones that come with cheap lift kits.

Blazers had 52's.

I am not arguing that doing that is the correct way....what I am arguing is its not designed to be installed like that. If that was the case, and you had to change the shim, cut the perch off, reset the pinion angle, and the reweld the perches back on....no one would buy the damn thing. How many kids do you think could do that in their driveway? All I am saying is, that when you buy a bolt on kit, you expect it to be exactly that.

So we just measured an NOS spring, 52 inches with a 6" arch to it....the springs they sent have an 11" arch to them, plus the extra spring and taper shim at 7/8".....given those measurements, I'd say its a 6" lift spring

rear springs are soft as fuck and when you load down on them they will compress, alot. and like i said before, they will settle with time and use, that extra inch will disapear.



there is the right way and the cheap/easy way, you can do it how ever you want, but dont expect the results to be the same.

Soft as fuck huh? Well riddle me this....how come it took 3 guys my size (6'3 and 235) to push it down sitting on it? No way the body would ever weigh that much...and furthermore even if it does compress over time, you couldnt drive it because of the driveshaft. And honestly, I don't think they compress much at all over time like stock ones do...I have a set of 16's on a truck I did 13 years ago and she hasn't sagged a bit.

Most 4" blazer lifts I have seen were done the cheap way, with blocks in the rear.....and they have that ugly rear squat where the headlights shoot to the sky :D

The vehicle should have an ever so slight rake toward the front....lift springs are usually pretty stout, not surprised it took that much weight, but they will break in a little, especially with some flexing on the trail.....

Every 4" lift I ever saw on a blazer required extending the rear driveshaft....back in the day, I lifted mine with a crappy 4" block and still had to lenghthen the rear shaft....I wish I would have done mine right with springs....I hated the way the rear squatted...

Can you post some pics so we can see just how bad it is?

If I can get back up there before he yanks them out I can post some.

I run 4" front springs & 5.5" Superlift rear springs (6leafs). When I first installed the rear springs the only time my rig would sit level was when the hardtop was on,tank was full & road trip stuff loaded up. I got the 'stinkbug' look when topless, but I would rather have that than a saggy butt. The shitty alumn shims cracked and spit out while wheelin wich then left me with loose u-bolts = rounded/bent spring perches. Seeing the bent perches is how I knoticed the shims were gone and u-bolts were loose. I was lucky the whole rearend didn't twist. I will NEVER run shims again, just to the job right and relocate the perches is what I have learned. The shims only lasted aprox 3yrs, dayly driving and weekend warrior duties.
Over the years I have gotten rid of the hardtop and the stinkbug look is perrty much gone from the setteling of the rear springs. I have even added more weight to the front w/454 install. Front springs are over 16yrs old and the rears are about 12yrs old now...damn time is flying by :homer:
Anyway...
.025c

Springs were stamped wrong I guess, they are sending the correct set...thanks for all the replies

bodies weigh 500+
tops are 300+
fuel tank. 200
frame is 200
plus all your shit in there.......... yeah you equaled it out :homer:

Most 4" blazer lifts I have seen were done the cheap way, with blocks in the rear.....and they have that ugly rear squat where the headlights shoot to the sky :D

The vehicle should have an ever so slight rake toward the front....lift springs are usually pretty stout, not surprised it took that much weight, but they will break in a little, especially with some flexing on the trail.....

Every 4" lift I ever saw on a blazer required extending the rear driveshaft....back in the day, I lifted mine with a crappy 4" block and still had to lenghthen the rear shaft....I wish I would have done mine right with springs....I hated the way the rear squatted...

Can you post some pics so we can see just how bad it is?

Really? My experience with 4" Blazer lifts, (one '90, one '89 ) Did not
need to lengthen driveshaft. I did lower t-case 1", to ease pinion angle.
both lifts were Pro-comp, with rear spring. and they both were (almost)
stock ride angles. With full fuel, "trail loading" tools, spares, water, etc, it
sits about 3/4" low in the rear.

Of course, the '89 now has the 14 bolt now, and that seems to have helped driveshaft length.

i wouldnt worry about it till your rig finished and wet. if they are the wrong springs your going to have to take them off, which is just as easy/hard with your rig put together.

They were the wrong springs as I said.....body 500 pounds? top 300 pounds? Wow I think your off on those weights a bit. A single wall fiberglass top weighs 125, and a body shell is only about 200.

They were the wrong springs as I said.....body 500 pounds? top 300 pounds? Wow I think your off on those weights a bit. A single wall fiberglass top weighs 125, and a body shell is only about 200.

Get out your scales cuz your calibrated arms are off a little if the body was only 200lbs I could put it on myself:laughing:. I've done a top several times by myself and its all of 200. Balance them on a scale and let us all know. My vote is for your new springs to set the same way as the old new ones.:flipoff2:

Its not worth my time to appease you all...everyone just wants to point fingers and bitch about someone else rather than try to help them. The new springs are perfect, so :flipoff2:

with no weight on them............

driveshaft fits, body back on it, with 500 pounds of tractor weights in it