Rear Springs Question

[tblazerdude]

I just recently installed a new rear axle so I could have a locker, and it was the first time in awhile I let the axle hang all the way down (full extension, BDS5500 shocks still attached, and the shocks are what stopped it from going lower) I noticed the springs came "loose". I have Z71 springs from a 2007 avalanche. I could literally take them right out, no spring compressor needed. This concerns me if I ever do some serious off-roading, since they could become unseated during suspension travel. I only have insulators on the top of the springs, and they are the original one that came with the trailblazer. My question is, have the springs sagged? What could I do to fix this? Not really looking for any additional lift.

 

[v7guy]

Those shocks should be 26" extended. The fox shock version is 27" extended.

I have the 3" lift with the 27" version and it takes some muscle, but with the sway bar connected I can remove the springs by hand, without the sway bar they would be loose. Plus my e brake/ abs/ and brake lines are being pulled tight.

If you have no lift spacer (you don't mention that you do), and the sway bar is connected (you don't mention that it isn't) then I would expect that your springs would be loose. Long shocks plus no spacers equals loose springs.

A locker or not makes no difference in the clearance in the shock/spring mounting.


If you just drive around the road to and from work I probably wouldn't worry much, just know that if you unload the suspension it could cause damage.

If you offroad much I would encourage you to take a long hard look at the parts you've chosen and what you're doing because you are on the very bottom slope of a steep learning curve that could get you and others hurt. Start reading a lot on offroadtb.

 

[tblazerdude]

I really appreciate your response and reply. I was starting to think, "Do I really need to bump my own thread? Am I the only one running Z71 rears and BDS5500?" I knew I wasn't, and I do need to join offroadTB. I know the locker (new rear end) has nothing to do with where my springs sit. It was the first time since my Bilstein HD's I had the suspension sit that low. It was clear to me that the BDS5500 were longer. It was an FYI, as to how I figured this out. I did not enjoy the ride of my bilstein HD's in the rear and replaced them with the BDS5500, and I enjoy it much more. Rebound pressure feels normal, not absent like it did on the Bilsteins w/ Z71's. I was thinking my Z71's have sagged since they were used, and I've put over 50k on them. My thought was a new set of Z71's would fix my problem, but you pointed out that it would not. Thanks. I could look into some custom spring seat/clamp that would hold them in place, or add 1'' spacers. I was looking to avoid more lift but the spacers might be my last resort.

 

[v7guy]

Don't get wrong, they may be sagging, you would know from a visual inspection.

 

[tblazerdude]

Maybe someone with a set of Z71's laying around could take a measurement of free length, so I have a base comparison. I'll measure mine tomorrow, (as well as visually inspect for sagging) and post the length. It's also a good time to check and see if they have unseated at all. This could also apply to anyone who just purchased a set of the Z71 springs, as they could measure them before install.

 

[The_Roadie]

I've got a set of spares lying around here somewhere. I'll measure them by the weekend, unless that's too late. I also have a set or two of 1" thin spacers you might be interested in. Too little for most of us on ORTB but they might be just the ticket for your problem.

 

[v7guy]

It's pretty obvious when they collapse. The coils end up almost touching or in some cases the coils overlap. If I was going to take a shot in the dark I'd say you got shocks that are too long. Since you don't have any significant lift the springs will fall out.

 

[tblazerdude]

Ok, back with some data:

The springs I have are Code YJJ P/N 15182559
The free length is between 17'' and 17 1/4''

If I lift one side of the truck I can not get the springs out. The sway bar holds the axle in place enough.

No signs of spring sag, coils look good and are generally evenly spaced.

If I lift both sides of the frame the springs are still a little loose, not as loose as it was without the sway bar. The first time I did this test the sway bar was disconnected, so as it seems the sway bar does play a role in how far the axle drops. Still disconcerning, but nearly as bad as it was. I would think a new set of spring seats or an additional set on the bottom of the spring would fix this, but who knows if it would add squeaks. So if other spring free lengths are similar, I will go with new spring seats and see if they stay in there. If that doesn't work, I will get 1'' rear spacers. I don't want to have a situation where I'm doing some severe suspension articulation, and think in the back of my head, "oh boy I hope the springs stay in place."