I'm not minded to pay a fiver each for one inch, M12 bolts (so on this car 50 quid all told just for the brake calipers alone) when I cannot see what's wrong with regular bolts just dabbed with Threadlock and done up a little tighter. Is there something I've overlooked? You will probably have guessed I'm old school and happy to be that way.
There are various grades of high tensile steel. If you use a lower grade than specified, you either won't be able to do them up to the specified torque - or you will risk over-stressing them, with a risk that they will fail.
Not a good idea for a safety-related item.
If they are stretch bolts then throw them away, they are one use only.
I pay around a tenner for the crankshaft bolts on my old Fiesta, and they're tightened up to a mental torque. Big long breaker bar, socket extension pivoted on an axle stand, and lots of grunting. I suppose that tensile bolts are meant for critical applications.
The wheel bearing nuts are weird single-use laminated things, which are just bonkers.
I have always received two of those bolts (different sizes) with a belt kit. I have got a half doazen or so new ones, I must put them on ebay.
I bought one recently because I have to change the front oil seal soon. Just waiting for a change in the weather :-) I only did the belt a couple of years ago, and I think I'll leave it in for a bit longer. The belt kits vary a bit. Some come with tensioner, bolt, and a water pump, since the job is such a pain. I remember doing the belt on a Capri - only took about half an hour. It had lost its teeth (harmlessly) on the way to my mum and dad's house. I just got the AA bloke to take us the rest of the way, and I changed it in the road outside their house - even had a spare belt in the boot. I wouldn't attempt that now :-)
Is this on your 420G? Didn't think stretch bolts were common then. And I've never seen them used on an ordinary car callipers.
and wouldn't they be UNF?
No idea, but quite possibly. Dave seems to be having some problems keeping up with all the cars I encounter. The one in question here is a
2015 Merc. I very much doubt there were such things as stretch bolts at all back in the 1960s! :-)
Funny nobody worried about such details back in the old days - yet the world didn't end!
The alternative isn't a good idea from a wallet-related PoV, though.
My mother does this. Whitters on about one thing then changes the subject while carrying on just using he, she & it about the new topic. Put more details in and we won't be left guessing.
What's the actual torque specification? Can't imagine they're actually specifying stretch bolts but they do tend to say "use new bolts" as they come pre-threadlocked.
and new pads come with the bolts, and they are not M12 by 1 inch
In that case, the wrong bolts would invalidate your insurance - which could make an even bigger hole in your wallet if detected.
Why on earth would pads come with bolts?? These bolts are M12 thread and about an inch long (obvs not exactly one inch - I'm just trying to get across how little you get in exchange for your five quid).
Surely if you have an expensive near new high performance car, you'd service it by the book?
But are you saying something like a pad change involves replacing stretch bolts?
I would but it's not mine.
Not suggesting any such thing, Dave. I think the confusion arose through a typo by Mr. Cheerful. These are the bolts that hold the brake
*calipers* to the hub carriers.
That's my understanding. I think it's just a play-it-safe way of ensuring threadlock (and the correct threadlock) is used.
They do with some VWs if you buy genuine, OE pads. It's because these bolts have to come out to replace the pads and the official manual says to use new bolts, because they come coated with threadlock, AIUI.
On some types you have to unbolt the calliper to change the pads.
Is this some form of theoretical question?
Might help if you described the actual problem.
Ah - right. So:-
'I'm not minded to pay a fiver each for one inch, M12 bolts (so on this car 50 quid all told just for the brake calipers alone) when I cannot see what's wrong with regular bolts just dabbed with Threadlock and done up a little tighter.'
doesn't actually refer to you?
Do they have to be removed to change the pads or discs?
If so, and they are one use stretch types I'd certainly replace them.
I tend to think the makers know best in this sort of safety critical situation.
Of course if it's not your car any bodge isn't going to effect you.
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