Snapped bolt heads and torque wrenches

Following on from my disc and pad change thread where I thought I had lost one of the bolts, it actually turned out that I didn't undertighten it, if anything, I overtightened the bolt and the head snapped off!

I have never had a torque wrench and would always just do things up as tight as they would go, being gentle with things like spark plugs.

But my latest episode got me thinking - should I invest in a torque wrench?

Should I buy one or should I stick to the school of theory that you should do things up as tight as they would go?

Buy a torque wrench

Halfords do two decent ones and with a trade card it's quite cheap.

Hand tight is good until something goes wrong

Following on from my disc and pad change thread where I thought I had lost one of the bolts, it actually turned out that I didn't undertighten it, if anything, I overtightened the bolt and the head snapped off!

 

I have never had a torque wrench and would always just do things up as tight as they would go, being gentle with things like spark plugs.

 

But my latest episode got me thinking - should I invest in a torque wrench?

 

Should I buy one or should I stick to the school of theory that you should do things up as tight as they would go?

This theory is simply asking for trouble and depending on what your actually tightening up

will bite you in the ass sooner or later.

You can apply way more torque to a bolt or nut than it should have very easily, all your

doing is stretching the thread though risking it failing straight away or at a later date.

A torque wrench is an essential piece of kit to have in my opinion. You`ll save yourself money, grief and possibly your life by tightening nuts and bolts to the recommended torque:)

Right then, I will go and invest in one, thanks guys. I guess my next question is how do I know what torque rating I should tighten various bits to? eg. wheel nuts, caliper slider bolts, that kind of stuff

Just had a quick look, as far as Halfords Pro wrenches go, there are two:

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_180255_langId_-1_categoryId_165469

or

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_178621_langId_-1_categoryId_165469

Should I go for the second one as it has a higher range 60nm - 300nm vs. 40nm - 200nm for the 1st one?

Right then, I will go and invest in one, thanks guys. I guess my next question is how do I know what torque rating I should tighten various bits to? eg. wheel nuts, caliper slider bolts, that kind of stuff

A workshop manual is an invaluable asset if you are determined to maintain your own car.

But I think an awful lot of that info is actually located in the club download section at the top of the main page.

They do a pro wrench that goes from 8nm to 60nm which is what you'll need for lots

of applications such as the caliper bolts, cam cover bolts etc etc

If your planning on doing all you own work i'd splash out and buy the 8 - 60 and the 60 - 300

If you look on the home page in the top left corner click on repair manuals and pretty much most things to do on a mkiv are covered inc torque figures

Just to give you an idea, the cam cover bolts are 8mn, wheel nuts are 105nm approx and

the crank pulley nut is 330nm

Thanks guys, appreciate the help / knowledge. Will drop round Halfords later this week.

I need to buy the same ones too...thanks for the links.

Group buy?

No need, I have a halfords trade card ;-)

Nice! I have access to one too, I'd be interested to see what that brings the cost down to...on some things like bulbs it's a great discount, on things like oils its marginal eg. £1, on tools its supposed to be decent.

you wont regret it- torque is very important!

i had a cheap one for years, upgraded to a halfords one about 6/7 years ago and its great. my low range one is a clarke from machine mart, but thats a pain in the a55 as it only has lb/ft force and inch pounds on the scale, so you have to use a conversion table for NM readings from toyota manuals. just something to consider if you look elsewhere not just halfords

Just print off a conversion table and pop it in your toolbox

i have......... they even provide one with the wrench! but i find it a pain in the a55, maybe i'm just lazy

ooh another thing- if the wrench at halfords is on offer, get them to check whether its cheaper or not on trade card rather than just using it- sometimes it can be more expensive as they only discount the "usual" price.

Thanks guys

Nice! I have access to one too, I'd be interested to see what that brings the cost down to...on some things like bulbs it's a great discount, on things like oils its marginal eg. £1, on tools its supposed to be decent.

The £85 torque wrench I got from halfords was £32 with my trade card

Hi Al, I don't know if it is store dependent or if you got yours a little while back but I called up yesterday and it was £39.99, still not a bad deal at all!

Can I use the wrenches with impact sockets too?

In all my years as a mechanic my experience is none mechanically trained punters tend to grossly overtighten things, especially wheel nuts and bolts. Once you have a year or two of getting the "feel" of how much effort on X length spanner equates to Y ft lbs, you tend not to use them except on critical engine components, you just get the knack. Having the knack means you instinctively feel a thread starting to pull out, or when undoing something any harder will result in it breaking. You still have the odd whoopsie, but until you gain a feel for things a cheapish torque wrench is vital.

Hi Al, I don't know if it is store dependent or if you got yours a little while back but I called up yesterday and it was £39.99, still not a bad deal at all!

 

Can I use the wrenches with impact sockets too?

Sorry, the torque wrench I got was the big one, and it was a year ago I bought it.

Just been to my local Halfords, they have the 3/8 drive 8nm - 60nm wrench in stock and the 1/2 drive 40nm - 200nm one in stock. The 1/2 drive 60nm - 300nm is out of stock...shall I wait for the latter to come back into stock or should I just get the 40nm - 200nm 1/2 drive one and be done with it?

I'd wait and then you will cover a much wider range of torque

and you can use whatever sockets you like with them

Thanks Dunk. What I think I'll do is jump in the car again on the way to the gym and go to a different branch slightly further away, hopefully they will have stock! I checked, for both of these, with a trade cars its just under £90, bargain!