When to use impacts vs hand tools

Is there a general rule on when you'd want to avoid using an impact on something and go for a hand tool instead?

I got my but kicked today trying to get an A/F sensor out of a Titan manifold and ended up using my impact to get it out. Had some threads to clean up, but cripes was it in there and I got lucky.

I'm not just wondering about the bigger power applications. Even smaller stuff like 10mm with a 3/8" impact vs hand.

I'm trying to avoid breaking crap and there is so much speculation in the field on topics like this.

Nissan Technician

It's no secret that I cut my teeth in the junk yard before becoming a tech, everything was 1/2" drive impact then, even 8mm Ford hood bolts.

Now, not so much. Anything that's threaded into an insert that's potted in plastic I remove by hand. Intake manifold bolts and small stuff like that I feel out with a ratchet. If the first couple don't fight I use an air ratchet. I prefer air ratchet to an impact for 3/8ths fasteners. Less violent, more control.

I'm also a huge fan of oxy/acetalyne!
I don't spend a lot of time screwing around. If an oxygen sensor is giving me a rough go, the torch comes out without much reservation.

Yeah, that's how I tend to work too. You just always have someone telling you when and when to not use heat or some other technique.

I tend to break a lot of the smaller 10mm stuff using my m12 3/8" impact. I'm working on using better judgement there, ha. Damn rust belt.

I ended up using the torch and 1/2" impact on that 02 sensor. I've never done that before, used the big impact on an o2.

I tried heat and a 1/2" long ratchet with no luck, just as someone comes over to tell me, "whatever you do don't heat it up or it will gall the treads when it comes out."

These types of comments, do you ever really know what is going to work? I feel like you just keep trying different techniques until something works and that becomes the proper way, since it worked.

One note on breaking bolts loose - from what I gather, slowly applying more and more force is what usually breaks stuff rather than quick shocks, which is what impacts can be so effective. Correct?

It's like the industry of speculation!



Nissan Technician

I've mucked up the threads on maybe one pipe. No big deal really. There's a thread restorer for it, and if you really did a thorough job pulling out the threads you can weld on a new bung or section of pipe. (Most of the time).
It just takes time to find the finesse.

I would sugjest laying off the power tools until you become proficient with just feel..
That will tell you when its time to break out the torch or the impact..
I've seen to many young techs turn a simple 1hr job into a all day thing becuse they snapped off a bolt head..
Remember the shop can only charge what the book says it takes for that job and they will only pay you that .. If you break a bolt that's on you.
Get it out no matter how long it takes but we only gonna pay you the 1 hour the book says it should of taken..
Do it again and you can roll your fancy shinny new Matco or Snap-on box out the door..

Wow, your boss is a real slave driver.

I would have been fired from or quit that place a long time ago!

Please don't take offense, this isn't a personal shot at you. I'm always amazed at the cultural difference between repair shops. I guess I'm just lucky to work for a guy who realises that shit happens.

I'm 58 so I impact everything I can not including small bolts. It's basically up to you. It also saves me a lot of time. My wife bought me this electric impact ratchet… I use the hell out of that thing! I'm careful with it when I'm tightening small stuff so as not to strip the threads out. I just bring it up snug and hand wrench the rest of the way... Still saves time doing it like this.

When taking bolts out an impact is less likely to shear a bolt than a lot of force on a short bar. When tightening I always run bolts in by hand, then a small battery impact or power ratchet the tighten using the appropriate hand tool. For spark plus depending on access tend to enter them by hand using a socket extension as a hand driver or a speed brace then hand torque. With spark plugs use a magnetic socket never the type with a rubber insert.

If assembling an engine the speed brace is again my tool of choice before torquing, especially for fitting cam carriers and covers and oil pans .

Yup spanners are made the correct length to suit the required tighten torque for. The bolt size.
But must confess I now have a set of US-Pro extra long aviation wrenches that now have become my tool of choice for a lot of jobs.

L

Tutti57 wrote: It's like the industry of speculation!

Ain't that the truth. :silly: Anecdotal evidence is about as good as it gets for us, unfortunately.

I see nothing wrong with the way you removed that O2, for what it's worth. Heat, no heat, impact, no impact, whatever. That sensor wasn't coming out cleanly no matter what you did.

There's a lot of those pitfalls in the industry. Can't always avoid them. Ever align a WK Jeep? The lower control arm is slotted for camber/caster. The rear bolts ALWAYS break off. Every. Time. First couple alignments, I spent hours trying to massage them out. Then I just started carrying the correct bolt/nut in my toolbox and charged accordingly. :lol: Snap 'em, beat the remains out, slap the shiny new bolts in.

Maybe I'm an animal? But I'll often use impacts in situations that I technically shouldn't. Whenever possible, I'll impact spark plugs out. Especially the 5.4L Triton engines. Reinstall by hand, obviously.

That is the preferred method of removal for Ford 3V spark plugs here as well.