impact air wrench

Newbie Joined: 17 Nov 2004 Posts: 13

Maybe not a direct renault question, but I did not find other place for this question.
I tried yesterday to remove the nut that keeps the driveshaft to the disk. It's a 30 mm bolt(or maybe 32, I'm not very sure). I used 1/2" wrench with about 1 meter rod (extension). It bent at the fulcrum.....

So, I decided to buy a impact air wrench system. Now, I do not know what to buy. I've seen some electric impact wrenches at decent prices but they ranges about 250 Nm (appx 200 Ft/Lbs). Don't know if it is enough. As the all mechanics are using air compresors tools, but the air impact wrenches range is so wide.....

What would be a proper tool to buy to handle that kind of torque? 200 Nm, 300 Nm, 500 Nm(appx 200 -> 400 Ft/Lbs)??

Site Subscriber Joined: 02 Oct 2004 Posts: 1575

http://www.retro-renault.com/viewtopic.php?t=1848 this might be usefull as regards compressors.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

With hub nuts air ratchets don't usually get them undone, usually its a breaker bar for them. Sometimes they do, if the cracks quick enough they will wind off but usually steady high leverage is whats needed on them.

I have to say I have not really struggled with the hub nuts.

I have a 24 inch 1/2 halfords breaker bar which I use. Wire brushing the driveshaft threads and wd-40 helps though.

Air ratchets etc are good for undoing things but not to be used for tightening really. 200ftlb's will be fine for pretty much anything on the car, aside from rusted on bits where the break off torques really high like say a hub nut.

Level 6 User Joined: 04 Nov 2004 Posts: 134

get yourself the right size socket a small extension bar, and a decent i.e. long, high pressure torque rench with that poundage and a little more and it they come undone easy peasy.

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

i wouldnt use a torwue wrench for undoing things.

i had to undo the hatchs hub yesterday, it was well 'ard!

i got a breaker bar (24" as well i think) thats usually enough but this one obviously hasnt been off much, so i have a length (1200 i think) of steel box section which i can slide over the end of the breaker bar...even then, with the car out of gear i was rolling the car forward by turning the nut!!! this was also with handbrake on!! so a lot of torque was being applied!

stuck in gear it finally gave...

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

normally I end up with the cars road wheel spinning on the ground so someone in the car with the foot on the brake also helps.

Gay Rights Activist Joined: 07 Apr 2004 Posts: 1268

elviscat wrote:

get yourself the right size socket a small extension bar, and a decent i.e. long, high pressure torque rench with that poundage and a little more and it they come undone easy peasy.

why the hell would you use a torque wrench??!

Site Subscriber Joined: 29 Dec 2004 Posts: 395

Torque wrenches usually have much longer handles for better leverage and are specifically designed for tightening and losening high torque parts.

It's the right tool for the job!

Site Subscriber Joined: 29 Dec 2004 Posts: 395

Or just a long bit of tubing over an ordinary ratchet and socket.
Needs to be a good ratchet though or it will just give way under that kind of pressure.

Gay Rights Activist Joined: 07 Apr 2004 Posts: 1268

no, they are used to tighten a fastner to a specific torque.

just becasue they have a long "handle", doesnt mean they are the right tool. the right tool would be a suitably long breaker bar...as discussed.

anyway it would be no longer than a 24" braeker bar!

Site Subscriber Joined: 29 Dec 2004 Posts: 395

I know that, but he's going to need a torque wrench to replace the nut afterwards anyway, so he might aswell buy one and try that to remove it first.

Gay Rights Activist Joined: 07 Apr 2004 Posts: 1268

JohnelP wrote:

I used 1/2" wrench with about 1 meter rod (extension). It bent at the fulcrum.....

why would he waste money on a Torque wrench to undo it, when a longer set-up already failed?!!

Site Subscriber Joined: 29 Dec 2004 Posts: 395

Like i said before, although a torque wrench is a tool designed for tightening to a specific torque. It has also been engineered to cope with much higher stress than a standard wrench, hence the long handle. If ordinary wrenches were designed to cope with the pressure they would be made longer which is why in the warranty for most tools like that states it does not cover the use of extention bars.

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

wouldnt like to use a torque wrench to undo things that are real tight. How can you get a torque wrench that is rated to the torque required plus a bit if you dont know how tight your rusted/siezed bolt/nut is?

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

mixpioneer wrote:

Like i said before, although a torque wrench is a tool designed for tightening to a specific torque. It has also been engineered to cope with much higher stress than a standard wrench, hence the long handle. If ordinary wrenches were designed to cope with the pressure they would be made longer which is why in the warranty for most tools like that states it does not cover the use of extention bars.

a torque wrench can handle more stress than a breaker bar?

Gay Rights Activist Joined: 07 Apr 2004 Posts: 1268

i give up! he obviously knows what he's talking about Rolling Eyes

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

i just use my 1/2" halfords ratchet + a steel tube table leg (or Simon's Maglite with the battery cap removed) for everything, hasn't broken yet Smile

Gay Rights Activist Joined: 07 Apr 2004 Posts: 1268

LOL that'll void the warranty you know!

Site Subscriber Joined: 29 Dec 2004 Posts: 395

We use a torque wrench to change the rear wheels on our tractors as nothing else will do the job. Have got through loads of spanners, ratchets, usually lucky if the socket doesnt split open aswell.

Have had no problems with our torque wrench.
It is 1m long and is rated at 100 - 500 ft/lbs

If theres anything on a car over 500 ft/lbs i'd be amazed

Gay Rights Activist Joined: 07 Apr 2004 Posts: 1268

right, your torque wrench is 1m long....therefore, ANY method of extension using the same socket WILL WORK...it doesnt have to be a torque wrench!!!!

using a torque wrench has no benefit over using a breaker bar of an equivalent length.

Newbie Joined: 17 Nov 2004 Posts: 13

Now i got it. Actually, to be honest, I did not have a breaker bar in the exact sense, I had a bar where the 1/2" 'father' (what you stick into the right size sockets) was sliding. I had an extension pipe of 1 meter (a pipe for old water installations) attached to it; But, still, overall it was 1 meter.
It was the little rather short sliding support bar that bent; the one that was inserted in the 1 m pipe.

Now i am thinking that the breaker bar has two articulation points for the socket, while my combination had only one stess articulation point where it bent. So, my mistake, sorry;

Now, back to the thread. Chris, what do you mean a breaker bar is better for undoing nuts (driveaxle nuts) than an air impact wrench?
The mecanics are not using breaker bars as far as i could see! Only air impact wrenches. And with impact wrench, in half a second they have any nut undone! What I do not know is the torque ratings of their tools.

I noticed the electrical impact wrenches do not go beyond 200 ft/lbs. Only the air tools go to 500 ft/lbs or more.

Hmm, do you believe a breaker bar is more reliable to have the job done than a air wrench tool?

Can I use regular tools from auto shops, or do they have to be Wurth or Kokon, or any real brand name?