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2006 GTO IBM 6 Speed
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So you know how there’s tight and there’s gudentite? Well the cradle was just tight.

I switched back to the stock wheels thinking the x9’s and weak rubber strut mounts were causing strut rub but .....nope. Put the front on ramps and had my son hop on the front and the wheel to strut gap remains....huh.

Did some up/down action with the jack while under there and was able to feel and ultimately see this, a very, very small smidge of movement that was causing the ruckus.

What this shows is how little play under a lot of load can cause a suspension clunk type noise. I'm raising the front of car up by the cradle, thump up, then if you look closely you can see the tiny shift/thump down when lowering the car back down.


I saw the movement when you brought the car down. This is the cradle moving?
 

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I see it now. Hmmn. I don't actually doubt you tested the bolt torque, but there's obviously not nearly enough clamping force. Wondering if the previous owner fubard something.

I guess order new subframe bolts from wretched, try to remove these and pray. Chase the threads when you get them out.
 

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Discussion Starter · #124 ·
I didn’t give much thought as why and how. Remember this is all after I ran over a plank in the road and cracked and bent a TSW Thruxton. Hit hard enough to push the strut all the way through the camber adjustment slot. Yes it was in stupid tight and no, the last alignment guy didn’t use the clevis to get the camber setting so it was free to move in.

I like to think the bolts were near their yield point, as if I felt them stretch within their elastic range, went ahead and stretched them more 👍.

Why just that corner was binding is beyond me, the impact was on the other side. I guess because there is just enough deflection on the frame rails that when jacking up either by the cradle via skid plate or small cradle rail up front(for testing)that the loose clamping force allowed the cradle to move while the two deflect away and back towards each other acting as two separate units as opposed to a single assembly?

Sorry that’s a dumb run-on but tightened it up, jacked it around, drove it around and no more sounds.

I’ll probably get replacement grade 10.2 bolts and swap em out eventually. Just glad it’s done and can move on to other projects.

Appreciate y’all’s feedback, constructive and otherwise.
 

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Discussion Starter · #125 ·
I saw the movement when you brought the car down. This is the cradle moving?
Yeah, view is looking behind the passenger front RR bushing, towards the firewall, sort of, right where the the FR corner of the cradle and frame rail meet. Didn’t see if the back of the cradle was shifting too, I kinda doubt it but not really. The cradle itself is pretty stout.
 

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2006 GTO IBM 6 Speed
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Yeah, view is looking behind the passenger front RR bushing, towards the firewall, sort of, right where the the FR corner of the cradle and frame rail meet. Didn’t see if the back of the cradle was shifting too, I kinda doubt it but not really. The cradle itself is pretty stout.
Ok just wondering because I get a similar creak but mine is temperature related. I'll hear it as the engine warms up and as it cools.
 

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The frame rails are not the fancy stiff high strength steel they use in newer vehicles. They are stout, but stuff bending slightly from an impact like you experienced is not out of the realm of possibility.
 

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Discussion Starter · #128 ·
The frame rails are not the fancy stiff high trength steel the use in newer vehicles. They are stout, but stuff bending slightly from an impact like you experienced is not out of the realm of possibility.
True. I actually pulled that bolt out to see if that cradle hole was elongated or cracked, which is what I expected to see and all looked good. I know deflection is normal and the cradle as a square is much stronger than the two parallel rails. I remember seeing breakaway points in the cradle that others have reported when hitting something as a way to prevent rail damage.
 

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Discussion Starter · #130 ·
Does anyone know cradle bolt length and size? Did a quick search to know avail.

My bro works in hardware so will go with some non-TTY, high strength stuff that I can torque to my hearts content.

Current bolts have to be at least 100 ‘-lbs
 

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Does anyone know cradle bolt length and size? Did a quick search to know avail.

My bro works in hardware so will go with some non-TTY, high strength stuff that I can torque to my hearts content.

Current bolts have to be at least 100 ‘-lbs
I dont but wretched does sell front cradle bolts
 

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Discussion Starter · #133 ·
I'm stock minus Magnaflow exhaust so I thought maybe the cradle or engine mounts were shifting around.
I’d doubt that but this thread proves just about what you expect is happening, isn’t.

I’m just glad I don’t do this for a living 🤣, and to think I was one college app away from pursuing auto mech
 

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Does anyone know cradle bolt length and size? Did a quick search to know avail.

My bro works in hardware so will go with some non-TTY, high strength stuff that I can torque to my hearts content.

Current bolts have to be at least 100 ‘-lbs
I dont but wretched does sell front cradle bolts
yeah, just get them from wretched. it's going to be difficult to find them the length you need with the OE-type coating.

 

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it's an M12-1.5-140mm class 10.9, btw, with a flanged hex head. the thread starts at about 132mm and it has a cone shaped nub on the end to help get the bolt in the hole to get started.
 

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Discussion Starter · #136 ·
it's an M12-1.5-140mm class 10.9, btw, with a flanged hex head. the thread starts at about 132mm and it has a cone shaped nub on the end to help get the bolt in the hole to get started.
it's an M12-1.5-140mm class 10.9, btw, with a flanged hex head. the thread starts at about 132mm and it has a cone shaped nub on the end to help get the bolt in the hole to get started.
Thx. I was able find the specs from some retailer somewhere. Asked my bro if he carries them at work and was able to get one similar but 130mm length. Doubt it has the nub and also doesn’t have the flange head also so he’s including washers.

I’m sure there’s more than 10mm extra length through the nut, not sure that the flange head vs washer matters.
 

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i don't think it does. washers can be better sometimes. Just remember whatever thickness that washer is, it takes away from the effective length of the bolt.

can you get 135 or 140mm?
 

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Discussion Starter · #138 ·
i don't think it does. washers can be better sometimes. Just remember whatever thickness that washer is, it takes away from the effective length of the bolt.

can you get 135 or 140mm?
130 actually, 15mm, ~1/2” short of another spec I read.

I’ll try to measure contact area to nut in rail to confirm the length will suffice.
 
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