Torque Wrench / Calibration Required?

[nickh1978]

Hello Forum,

While working on my s60 at the weekend, I managed to sheer one of the M10 bolts that secure the cross-bar to the strut mounts....

I had dialled in the correct Nm setting (35Nm), but the wrench never 'clicked' to indicate the correct torque setting had been reached when tightening the bolt (used several times on wheel nuts and worked flawlessly previously).

I've been reading that a torque wrench needs to be 'wound back' when it is not in-use (which I didn't do) and wondering whether this may be the problem? i.e. its no longer calibrated.

I was planning on dropping into my local garage to see whether they would calibrate it - is this something that a garage would typically do?

For reference, the wrench is a SEALEY AK624B Micrometer Torque Wrench (http://www.sealey.co.uk/PLPageBuilde...roductid=20122)

Cheers, N.

[oragex]

Originally Posted by nickh1978

I've been reading that a torque wrench needs to be 'wound back' when it is not in-use (which I didn't do) and wondering whether this may be the problem? i.e. its no longer calibrated.

Unfortunately, you answered your own question. This is true on all wrenches. I'm not sure (and wondering) if there's anything it can be done now. The springs inside sit under pressure so I guess trying to disassemble it's not going to be fun.

[cheshired5]

You could try winding up the wrench to its maximum then loosening to the minimum safe level and repeat to exercise the spring.
Failing that, unless recalibration is very cheap, I'd be inclined to buy a new wrench as they are extremely cheap and plenty good enough for a hobby mechanic and it's only when you head towards 300Nm wrenches that costs become serious.

[benx]

I made the same mistake - I used mine at 140 Nm then promptly left it for about a year You can get them recalibrated. I looked into this and it was about 50 quid plus postage, so for my wrench just wasn't worth it.

Not sure this will explain why you sheared the bolt though. If left stored wound up you would think this could only weaken the spring, resulting in under-tightening?

[oragex]

You can also easily 'home test' the wrench, a few videos on youtube

[nickh1978]

Thanks all, think I'll probably just get myself a new one and put this down to 'lessons learnt'.....

[barrybritcher]

PS do not undo the bolts on the triangle mount (which I think is what you are referring to) as the weld to the body can snap. to remove the x bar only use the vertical bolts and the engine mount

guess how I learned

[barrybritcher]

think the word I was looking for was captive nut can snap

[nickh1978]

Thanks Barry, I hadn't heard this one before but will bear it in mind in the future. Weld looks fine, but I can see where you are coming from.

In the end I purchased a new SEALEY AK624. Works like a charm and I'm making sure I wind off the torque setting before I put it away :-)

[GreenBrick]

I tested mine with bottles of water on the handle, at a known distance from the socket. It turned out that for the range of torques used for cylinder head bolts, it was clicking at about 3/4 of the torque it was reading. I made the mistake of using it to undo some head bolts, which I instantly regretted.
Before I put my Jeep back together I am going to buy a new one, as I don't trust it very much now and it was only a cheap halfrauds one anyhoo.