[czkn88pl]

Originally Posted by TRZ06

YES, the rear cradle bushings will resolve your issues. That is the ONLY weak point in the ZL1 & SS 1LE suspension from a handling perspective.

OK, thank you very much for that informations.

Right now main problem is that the OEM ZL1 1LE rear cradle bushings are out of stock... (checked here https://www.gmperformancemotor.com/parts/84341929.html and https://wildhammermotorsports.com/ca...ssis-upgrades/ ). Wildhummer wrote me that even need wait for that part 6+ months...

Then maybe somebody from you could help me get this part ?
Or... BMR also have some this rear cradle bushings but in 3 options:
https://www.bmrsuspension.com/?page=...=121&catid=472

What do you think ?

[TheRealJA105]

The BMR lockout kit greatly improves the rear end and installation is way less involved. Well worthwhile mod!

[h018871]

This post has been SUPER helpful. I very much appreciate OP's honesty and candidness with his evaluation of the changes made to his car.

Apologies for bringing this up again, I see JCunningham's point however it is opposite to the instructions from GM. GM Performance specifically states to install the lower bushing first.
I don't have my kit yet, still back-ordered, and don't know what the "nub" is that is causing the bushings not to touch both top/bottom of the cradle.
Folks that have these installed and you followed the instructions, have you seen your alignment change or the cradle settle towards the upper bushing?

Originally Posted by JCunningham

The bushings are to tall for the cradle pocket. See how your bushing is here. The top is not fully seated. The top has to be fully seated. The bushings touch each other befor both are fully seated. The way you did it the the 1st one to fully seat is the one that will be fully seated leaving the other out like in your pic. Sometimes it will be the top sometimes it will be the bottom. The top bushing is what determines if the cradle will be straight or cocked. When installing these bushings just as the manual says you have to install the top bushing 1st and make sure it is fully seated. Then you install the bottom and when the bottom bushing hits the top bushing the bottom bushing will still be sticking out. In this pic the 2 bushings are touching each other and neither can go farther into the pocket. Just as mine are now. The only way to correct this would be for me to tap the drain holes on the bottom bushing and use a slide hammer to pull the bottom bushing out enough to put something in between the bottom bushing and the cradle then tighten the bolt bringing the top bushing down. Your way would work it GM had made these right and not put that nub inside so the the bushing touched. That nub does nothing but make these bushings to tall for the cradle bushing pocket.

[JCunningham]

Originally Posted by h018871

This post has been SUPER helpful. I very much appreciate OP's honesty and candidness with his evaluation of the changes made to his car.

Apologies for bringing this up again, I see JCunningham's point however it is opposite to the instructions from GM. GM Performance specifically states to install the lower bushing first.
I don't have my kit yet, still back-ordered, and don't know what the "nub" is that is causing the bushings not to touch both top/bottom of the cradle.
Folks that have these installed and you followed the instructions, have you seen your alignment change or the cradle settle towards the upper bushing?

they put out 2 sets of instructions. the 1st sets were wrong saying the bottom had to go in 1st. the 2nd were right saying the top has to go in 1st. think about it. if the top is not fully seated in the cradle the weight of the car could push the cradle up and screwing up your alignment. the top bushing has to be bottomed out on the cradle.

[travislambert]

Originally Posted by JCunningham

they put out 2 sets of instructions. the 1st sets were wrong saying the bottom had to go in 1st. the 2nd were right saying the top has to go in 1st. think about it. if the top is not fully seated in the cradle the weight of the car could push the cradle up and screwing up your alignment. the top bushing has to be bottomed out on the cradle.

I don't like to name drop, but I spoke with THE authority on the matter. He said it makes NO DIFFERENCE. It's likely just in the instructions the way it is to ensure the bushings are all installed the same way. That's what is important.

This falls perfectly in line with my experience. You guys act like 1/16" difference in height between the cradle and body is going to be some major problem. My gap is opposite the instructions and I absolutely run the crap out of my car on the track. It hasn't moved a fraction. I could just as easily post some bogus theory about how the bushing would move the other direction.

The assumption that the bushings will move within the cradle is wrong. It's a theoretical problem that doesn't happen. The cradle bushings aren't going to move...either direction...whether the gap is on the bottom or top... IT DOESN'T MOVE. If they could move, they would design them differently.

Honestly, I regret posting the video trying to help people. No good deed goes unpunished I guess. If you're installing these, feel free to choose whatever method you want. A person can still use the method I posted and get the gap whichever side they choose. By all means, follow the directions, but if you screw up as I did, IT MAKES ZERO DIFFERENCE! Just make sure you get them all the same.

[h018871]

Thx Travis. Sameness is common sense.........not necessarily common
KISS, keep it simple

[JCunningham]

you and your authority have no idea what they're talking about. to many ****ing retards on this form that have no mechanical sense at all. If i can move those bushings down with a few wacks of a hammer they're going to eventually move and your cradles going to be crooked. but its your car so who gives a ****. This is a reason professionals dont come on forums.

[travislambert]

Originally Posted by JCunningham

you and your authority have no idea what they're talking about. to many ****ing retards on this form that have no mechanical sense at all. If i can move those bushings down with a few wacks of a hammer they're going to eventually move and your cradles going to be crooked. but its your car so who gives a ****. This is a reason professionals dont come on forums.

Just because you do automotive work for a living doesn't mean your theories are always correct. There are countless examples of "professionals" messing up cars. In fact, know-it-all "professionals" are why many people cringe when they need to take their car to get it worked on. People turn to the forums to do things for themselves, because "professionals" are often the same folks who struggled in school with objective tests. When these people get out into the world they're no longer tested objectively, and over time they start to think they know everything because nobody is there to tell them otherwise. Meanwhile, the guys who excelled at academics, because they actually know what they are talking about, go on in life to become engineers. These engineers work to design things like suspension systems for cars. It's laughable when the people in garages with GEDs hop on forums, call themselves "professionals" and act like they know more about cars than the engineers designing them.

You're simply wrong about this, so please stop posting bogus theories on my thread. Go start a new thread and post all of the bad info you want. I won't intervene.

The bushings don't move. You just have a theory with no evidence...I have the real-world tested counterexample to your theory in my garage. It would literally take something as severe as a car accident to get them to move. In a car accident, it isn't going to make a difference whether you put that negligible gap on the top or bottom, it could move either way.

Even if they did move, the movement of the bushing alone isn't going to change the alignment. Anything that would impact the alignment in any meaningful way is self-contained within the cradle. Even if the bushings moved on just one side and not the other, which again, they don't move, the cradle's relationship to the ground, the toe, the camber, the sway bar, nothing changes because it's all self-contained within the cradle assembly.

The only suspension pieces that bridge the gap between the cradle and body are the the shocks and springs. Again assuming the bushings move, which they don't, a 1/16" side-to-side difference in the compression of the springs and shocks isn't going to make any difference. There's probably more delta than that naturally just due to the fact that the weight of the car isn't perfectly distributed. If you think about the weight distribution differences between drivers of different weight, or even the difference between passenger/no passenger, it's easy to see the compression of the springs and shocks is going to differ by more than 1/16" side-to-side.

[Alpha1BC]

Originally Posted by travislambert

Just because you do automotive work for a living doesn't mean your theories are always correct. There are countless examples of "professionals" messing up cars. In fact, know-it-all "professionals" are why many people cringe when they need to take their car to get it worked on. People turn to the forums to do things for themselves, because "professionals" are often the same folks who struggled in school with objective tests. When these people get out into the world they're no longer tested objectively, and over time they start to think they know everything because nobody is there to tell them otherwise. Meanwhile, the guys who excelled at academics, because they actually know what they are talking about, go on in life to become engineers. These engineers work to design things like suspension systems for cars. It's laughable when the people in garages with GEDs hop on forums, call themselves "professionals" and act like they know more about cars than the engineers designing them.

You're simply wrong about this, so please stop posting bogus theories on my thread. Go start a new thread and post all of the bad info you want. I won't intervene.

The bushings don't move. You just have a theory with no evidence...I have the real-world tested counterexample to your theory in my garage. It would literally take something as severe as a car accident to get them to move. In a car accident, it isn't going to make a difference whether you put that negligible gap on the top or bottom, it could move either way.

Even if they did move, the movement of the bushing alone isn't going to change the alignment. Anything that would impact the alignment in any meaningful way is self-contained within the cradle. Even if the bushings moved on just one side and not the other, which again, they don't move, the cradle's relationship to the ground, the toe, the camber, the sway bar, nothing changes because it's all self-contained within the cradle assembly.

The only suspension pieces that bridge the gap between the cradle and body are the the shocks and springs. Again assuming the bushings move, which they don't, a 1/16" side-to-side difference in the compression of the springs and shocks isn't going to make any difference. There's probably more delta than that naturally just due to the fact that the weight of the car isn't perfectly distributed. If you think about the weight distribution differences between drivers of different weight, or even the difference between passenger/no passenger, it's easy to see the compression of the springs and shocks is going to differ by more than 1/16" side-to-side.

I agree with Travis on this one. Just because the mounts can move via hitting with a hammer doesn't mean they'll move on the vehicle. The cradle doesn't do much in terms of reacting high-energy vertical loads; that's handled by the springs/roll bar/dampers. The loading the mounts see is almost purely lateral and longitudinal. Any vertical load that does get transferred through is likely in the ballpark of 1 kN or less, which would be roughly equivalent to a 250 lb person standing on it. It's also not going to have the energy of a blow from a hammer since the bushing and spherical joints act to absorb and deflect the energy from wheel impact loads before they reach the cradle.

If you do manage to get enough energy transferred to vertically moce the cradle on the mounts like that, there's likely a) some suspension component that's binding that or otherwise damaged and requires replacing, b) hit something so hard that other suspension components are likely damaged, or c) something hit the cradle directly. Any of these scenarios would be known to the driver if they pay any attention to how their vehicle feels normally and would require at least an alignment check if not an actual alignment. The change in instructions doesn't invalidate the old instructions, it was probably just done to make the cradle more robust to moving in situations like this and it might as well be done that way since it's free. It's also better in terms of tolerances since the only tolerance you have between the cradle and body is the thickness of the upper flange rather than the stack of tolerances through the entire bushing, but in actuality is negligible.

[L78toLT1]

I installed the solid bushings a few weeks ago. For what it's worth, I installed the top bushings flush with the cradle. I was very surprised that my alignment was still spot on. I knew the car felt fine, but was certainly surprised that the alignment was unaffected.

[SCCAForums]

3 questions:

What is the difference between the BMR Delrin and the BMR Lock out? From the pics, the lock out kit seems to still use rubber bushings? So would the delirin setup be most preferred for the track?

What about whichever is best from BMR vs. GM Solid Cradle Bushing Kit? Which is best?

If converting a ZL1 with factory MRC shocks, what do you need to do if swapping to a 1LE DSSV shock setup? Do they make cancellors for the MRC Electronics?

Best regards,
Dave

[Alpha1BC]

Originally Posted by SCCAForums

3 questions:

What is the difference between the BMR Delrin and the BMR Lock out? From the pics, the lock out kit seems to still use rubber bushings? So would the delirin setup be most preferred for the track?

What about whichever is best from BMR vs. GM Solid Cradle Bushing Kit? Which is best?

If converting a ZL1 with factory MRC shocks, what do you need to do if swapping to a 1LE DSSV shock setup? Do they make cancellors for the MRC Electronics?

Best regards,
Dave

1) BMR lockout is just a piece that fills the voids in the stock bushings to increase the bushing rate while the delrin bushing is a complete replacement. Delrin will be a stiffer solution but will be more involved to install since you have to remove the stock bushings first.

2) I'd argue GMs are the better choice than delrin for quality. Not only did GM fully test the Al on the ZL1 1LE (while BMR likely did not), aluminum has higher strength even though it's not quite as stiff IIRC. From a driving perspective, both would be a significant improvement over the stock bushings and I doubt many would be able to feel the stiffness difference between the two materials.

3) Yes, there are resistors you can buy to fake out the damper controller. Here's one example: https://www.phastekperformance.com/a...6-401002-n.htm

[travislambert]

I have the KW kit for the MRC delete. I was pretty impressed by the quality and I've never had a single hiccup with it.

https://wildhammermotorsports.com/ca...w-suspensions/

[SCCAForums]

I just got the 1LE aluminum bushing cradle kit, from GM. Took about 1 month to get. Instructions still say bottom bushing first. I’d like to see a copy and version number of a different set of instructions.

Here’s my pic, which just arrived new yesterday.

Best Regards,
Dave