how tight trailing arm bolt
Thread Starter
Melting Slicks
Joined: May 2003
Posts: 2,076
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From: Dyersburg TN
how tight trailing arm bolt
having t-arms rebuilt and wondered how tight trailing arm pivot bolts need to be? I know you can't just crank it down because the arms must move, but I don't want them to fall off either.
thanks
thanks
Race Director
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From: Chino CA
Thread Starter
Melting Slicks
Joined: May 2003
Posts: 2,076
Likes: 281
From: Dyersburg TN
Vansteel said
I asked the guys at Vansteel (they rebuilt arms for me) and they said: "Do not torque the pivot and nut. Get it tight enough to drop the cotter pin through the hole. Even if you could torque the nut, I would advise against it. If you do not have enough shims in the pocket, you can collapse the frame pocket in a bit which is not a good thing."
Race Director
Joined: Feb 2006
Posts: 12,239
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From: Chino CA
I asked the guys at Vansteel (they rebuilt arms for me) and they said: "Do not torque the pivot and nut. Get it tight enough to drop the cotter pin through the hole. Even if you could torque the nut, I would advise against it. If you do not have enough shims in the pocket, you can collapse the frame pocket in a bit which is not a good thing."
Just get the cotter pin in...
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Race Director
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Hope you enjoy changing trailing arm bushings..........
Thread Starter
Melting Slicks
Joined: May 2003
Posts: 2,076
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From: Dyersburg TN
already
One is already back on, the other in the box on my workbench. I destroyed the strut rod / shock bolts in removal as well as used the sawsall on the pivot bolt (drivers side). The passenger was the one with the bad wheel bearing, I just pulled the driver because I saw the bushings were shot on the removed passenger side.
given a choice between doing this job again and rebuilding ten engines, I would say 'raise the hood and get the hoist out'
given a choice between doing this job again and rebuilding ten engines, I would say 'raise the hood and get the hoist out'
Team Owner
Joined: Jul 2004
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From: Redondo Beach, California
I asked the guys at Vansteel they said: "Do not torque the pivot and nut. Get it tight enough to drop the cotter pin through the hole. Even if you could torque the nut, I would advise against it. If you do not have enough shims in the pocket, you can collapse the frame pocket in a bit which is not a good thing."
Race Director
Joined: Mar 2006
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From: Florida
I asked the guys at Vansteel (they rebuilt arms for me) and they said: "Do not torque the pivot and nut. Get it tight enough to drop the cotter pin through the hole. Even if you could torque the nut, I would advise against it. If you do not have enough shims in the pocket, you can collapse the frame pocket in a bit which is not a good thing."
The swaged inner barrel is not supposed to pivot on the bolt. If it's not torqued that won't happen.
Also, if you are collapsing the frame pocket by torquing, you don't have the correct thickness of shims installed.
Follow the GM service manual.
Race Director
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Why the bolt torque is not that important. The trailing arm bolt does not function as a bolt. It functions as a pin. The trailing arm bushing and shims positions the trailing arm in the frame and keeps the trailing arm from moving sideways. The trailing arm nut and cotter pin mainly just make sure the trailing arm bolt doesn't slide out of place. ...Anyhow that's the way I see it.
Team Owner
Joined: Jul 2004
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From: Redondo Beach, California
I'm wondering if you understood what I was saying. If you really wanted, you wouldn't have to use a bolt to attach the trailing arm to the frame. Take a cylindrical steel bar that has the same diameter as tthe trailing arm bolt shank, cut it to the appropriate length, drill two holes in it for cotter pins at the extreme ends. Use this device, a pin, to attach the trailing arm to the frame and then insert the cotter pins at the end of the pin to keep it from working loose.
(Of course there's a strength issue with the cotter pins, maybe something stronger to retain the pin would be better.)
Race Director
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I understood exactly what you said. Seems you're not familiar with how suspension bushings work and why the trailing arm bushing depends on the clamping force of the torqued nut and bolt to function properly. The bolt is anything but a simple 'pin'.
This is a very common misconception.
This is a very common misconception.
Race Director
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All rubber suspension bushings work on the same principle- the flex/torsion of the rubber material between the inner and outer shells is where the movement takes place, not the rubber sliding on a pin or housing.