Is it always safe to put an impact on a strut nut?

[norakat]

Is it always safe to use an impact on a strut nut?

When I tightened my strut nut with a medium breaker bar, you can feel after it snugs, the flexing of rubber (assuming that is the strut mount).

Some manufacturers actually recommend using an impact; that it is the only way to tighten their product like this company -

However on Toyota and Lexus struts, there is a groove on the strut rod and mount that prevents the rod from rotating in relation to the mount. So in this case is it still safe to put the impact on the strut rod nut? Can you damage the strut mount?

I have a strongest Milwaukee Lithium Ion Impact which boasts “1400 ft-lbs of nut busting torque”. I don’t want to rip my strut mount apart; but at the shops you see them use the pneumatic impact (which is a weaker impact) on the strut nuts all the time.

 

[rayra]

That “1400 ft-lbs of nut busting torque” is for taking frozen nuts OFF, NOT for putting things ON.

Is it not adjustable, as with an air tool?

And is there not a torque spec for the strut nut?

Either way, I would not sit there and hammer on it. Run it down until the first stop. Use a breaker bar if you think it needs more.

 

[norakat]

That “1400 ft-lbs of nut busting torque” is for taking frozen nuts OFF, NOT for putting things ON.

Is it not adjustable, as with an air tool?

And is there not a torque spec for the strut nut?

Either way, I would not sit there and hammer on it. Run it down until the first stop. Use a breaker bar if you think it needs more.

On a recent job I torqued it to spec 59 ft-lb and it was still rattling making clunking noises. I tightened w a breaker but after watching the video above was thinking of giving it a few zips w the impact like it suggested.

I was just worried I might damage something..

 

[toddmorr]

Kyb says specifically to not use an impact on their struts and mounts in this area.

 

[kaymccampbell]

I've always given them a zip with the air wrench, till they're down and get the first real dugga or two. Then I check the torque spec. If it's still loose-ish, then I just let er rip with the air wrench. Now the the little bolts that hold the top plate to the car get done by hand.

 

[rooster59]

I would say 1400 ft lbs is way too much.

 

[CraigStu]

I generally use my air impact. But it is adjustable so I use the lightest setting.

 

[norakat]

Kyb says specifically to not use an impact on their struts and mounts in this area.

That’s interesting. OEMs are KYB. Do you happen to have a link or document?

 

[toddmorr]

Kyb says that in the paperwork enclosed with the strut, they say it "weakens the threads".

 

[RumRiver5.0]

I've watched and known of people air busting down struts and axle nuts and have nothing but problems. Can you get away with it? Maybe but torque specs are stated for this very reason.

 

[Squankum]

Man in video is silly. You can do it with hand tools. Holding an L-shaped Allen key with one hand while turning the ratchet/breaker bar/some other lever arm with the other? Of course not.

I've been using two hand tools (and a socket that allows you to put an Allen bit (connected to one ratchet) through the top) since the 90's. Call me boring by-the-book guy.

When it comes to disassembly, now that I have air tools, sure, go for it. The goal is to avoid spinning the shaft and making the seal unhappy. Of course, if you use your air gun responsibly, and maybe put a hand/finger on the chromed rod to feel so you know it's not spinning, sure.

 

[39CAMC]

I've been using two hand tools (and a socket that allows you to put an Allen bit (connected to one ratchet) through the top) since the 90's. Call me boring by-the-book guy.

When it comes to disassembly, now that I have air tools, sure, go for it. The goal is to avoid spinning the shaft and making the seal unhappy. Of course, if you use your air gun responsibly, and maybe put a hand/finger on the chromed rod to feel so you know it's not spinning, sure.

The threads being too weak thing is silly, IMO. Yes of course, big enough impact can strip anything so if you lack any mechanical judgement and find yourself breaking large studs with impacts all the time then put the impact down and use hand tools.

Squankum is correct though. The seals aren't designed to be spun quickly and are the real concern. Triple time if its an adjustable strut like a Koni. But there are a lot of struts where you can't get anything but a socket down in the strut bearing and almost have to use an impact. Keep your hand on the rod to make sure its not spinning and be gentle. I don't know if the shaft turning matters for the magnetic ride struts any more than regular ones, but I never use an impact on these - $1000++++ struts scare me - but so far all of those have been easy to access with strut sockets (the ones with the window cut out of them for a wrench to hold the shaft)

Like everything, its a judgement call.

DaveW

 

[Wrench97]

They do not want the strut rod to spin fast and heat up and damage the seal, and if you over tighten using a impact there is a good chance of snapping the top threaded part of the shaft off. That said I do usually use a impact to remove and install the nuts some struts are almost impossible to do with a deep off set box and allen socket.

 

[Squankum]

My strut nut tools, for my little world (80's watercooled VW.)

My first, made by me, using a Craftsman SAE socket and primitive hand tools? Mill file and lots of time, I think. Hacksaw? Dremel? I don't think I had a Dremel that year... I made two flats for a Crescent wrench so I could put a 5 or 6mm hex bit through the center.



Another hint that it was hand tools: I sure quit early on side two! Gave it a try, it worked, done.



Then I bought a proper "special tool" -- manufactured by Schley Products, Inc., then modified by Techtonics Tuning on a lathe for better clearance into the depths of the stamped steel upper strut retainer. (Still not enough clearance, this thing only fits one of two front strut retainers on my GTI.) I think I see similar clearancing on the socket in the video above.



Oodles of clearance through the hole:

 

[rjacobs]

Kyb says that in the paperwork enclosed with the strut, they say it "weakens the threads".

An impact, no matter the direction, can always weaken the threads on anything. Im always very careful with my impact due to this... especially loosening lug nuts. I always break them loose with a breaker bar first.

 

[Squankum]

Putting away the above sockets, I found this one! 7/8's deep socket again, but with a window I cut into it with a Dremel.

 

[norakat]

I've watched and known of people air busting down struts and axle nuts and have nothing but problems. Can you get away with it? Maybe but torque specs are stated for this very reason.

Yeah but on a recent job I torqued my font strut nuts to spec - 59 ft-lbs and I had problems on one side - clunking / rattling. I later re-tightened with a 16” breaker bar and it turned very easily about 3/4 turn then stopped at which point you can feel the flex of shock mount rubber. After that the clunking went away.

 

[firebirdparts]

As long as you don’t snap it off, I am not aware of anything it could hurt.

 

[dchawk81]

Kyb says that in the paperwork enclosed with the strut, they say it "weakens the threads".

I'd like to see that paperwork. Maybe they mean don't "screw" the bolt through the holes with an impact. Meaning, line the holes up good enough that you can push it through by hand.

 

[v10climber]

You can absolutely damage struts (especially adjustable ones) by using an impact on them. That doesn't stop people though and I'd wager most people who have an impact available to them will use it. You just have to be careful and pay attention to what you're doing.