Author Topic: Installing shocks with an impact wrench  (Read 1551 times)

Offline JohnnyPopper

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Installing shocks with an impact wrench
« on: November 23, 2023, 04:45:12 PM »
The supplier states that using an impact wrench may damage the shock.

Any truth to that from your experience?

I recently changed my old ones to KYB and the left rear froze after a couple of weeks.

It's quite an experience to have your bed start oscillating violently upon hitting a bump! Like it's going to tear the truck apart. 

Changing them again to Bilstein and thought I'd ask.
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline Shifty

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Re: Installing shocks with an impact wrench
« Reply #1 on: November 27, 2023, 10:12:53 AM »
I don't know about damaging the shock, but they sure damaged my elbow trying to remove the old Monroe Gas Mags that someone definitely used an impact to install.  I had a cheater-bar, and one foot on the diff-tube, one on the brake drum trying to get it loose (no rust, but still soaked with PB Blaster).  Luckily, it gave the same time my elbow did....took two years to get the elbow back BTW.   :o
87 V20 Standard Cab Longbed (current)

87 R30 3+3 Longbed (days of yore)

98 C2500 ext cab longbed

Offline Scott91370

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Re: Installing shocks with an impact wrench
« Reply #2 on: November 27, 2023, 04:49:47 PM »
Since shocks do not travel in a straight line and you tighten them down too far they won't have needed  movement.
Don't know if it will damage them but seem unnecessary. 

Offline VileZambonie

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Re: Installing shocks with an impact wrench
« Reply #3 on: November 27, 2023, 05:32:31 PM »
Using an impact to drive on a nut that compresses a bushing with the potential of 1100 ft-lbs when 75 is spec... they gotta put warning labels on everything these days.
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Offline JohnnyPopper

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Re: Installing shocks with an impact wrench
« Reply #4 on: November 27, 2023, 08:04:11 PM »
Using an impact to drive on a nut that compresses a bushing with the potential of 1100 ft-lbs when 75 is spec... they gotta put warning labels on everything these days.

Ah, makes sense. If too much torque is applied to the point where the shaft bends could be a problem.

I'm sure bd could articulate the physics, as well as many others here. I plan on being a physicist in a couple hundred years from now. Seriously. Just not today...

Thanks guys!!!
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline Shifty

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Re: Installing shocks with an impact wrench
« Reply #5 on: November 28, 2023, 09:24:26 AM »
Using an impact to drive on a nut that compresses a bushing with the potential of 1100 ft-lbs when 75 is spec... they gotta put warning labels on everything these days.
Too many NASCAR viewers.... ;)
87 V20 Standard Cab Longbed (current)

87 R30 3+3 Longbed (days of yore)

98 C2500 ext cab longbed

Offline bd

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Re: Installing shocks with an impact wrench
« Reply #6 on: November 28, 2023, 06:59:25 PM »
Adding two more cents, although every threaded fastener has a specified torque, shock mount bolt/stud torques aren't critical values as long as they aren't severely off target, meaning sufficiently tight that the fasteners suitably compress the bushings and won't loosen with use yet not so tight that the bushings distort excessively or the threads strip. 

Generally, shock eye bushings have inner sleeves that limit the bushing crush.  Once the bolt or nut seats against the sleeve it won't compress the bushing any further, regardless of applied torque.  Tightening the fasteners too much further beyond seating the sleeves only stresses the threads (and the next guy who has to service the shocks).

Threaded pins that protrude axially from the ends of shocks can be less forgiving.  Most pins are only partially threaded or have shoulders that limit nut travel, thus, bushing compression.  But, some have no thread limiting features and bushings can compress to the point of splitting.  Installer beware.

Ultimately, one shouldn't use an impact wrench until (s)he has the experience to use it appropriately.  When in question, use a torque wrench and some anti-seize.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Shifty

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Re: Installing shocks with an impact wrench
« Reply #7 on: November 29, 2023, 09:26:51 AM »
BD, you have a Delorean with a flux capacitor?  The previous owner of my truck could use good advice....
87 V20 Standard Cab Longbed (current)

87 R30 3+3 Longbed (days of yore)

98 C2500 ext cab longbed

Offline bd

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Re: Installing shocks with an impact wrench
« Reply #8 on: November 29, 2023, 10:05:57 AM »
Got rid of them.  Been to the future.  Came back to ride it out.   ::)

If only foresight was 20/20.   :(
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Shifty

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Re: Installing shocks with an impact wrench
« Reply #9 on: November 29, 2023, 12:56:04 PM »
 ;)
87 V20 Standard Cab Longbed (current)

87 R30 3+3 Longbed (days of yore)

98 C2500 ext cab longbed

Offline Captkaos

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Re: Installing shocks with an impact wrench
« Reply #10 on: November 30, 2023, 05:27:44 PM »
Got rid of them.  Been to the future.  Came back to ride it out.   ::)

If only foresight was 20/20.   :(

LOL