Engine stand mounting bolts failed

[RrogerD]

My son has purchased an engine stand from Halfords rated at 340kg. He is swapping over the engine in his BMW from the 4-cyclinder to the 6-cyclinder.

The stand to engine fixings are 4 bolts that screw into the end of the block and the whole thing simply 'hangs' from these. He purchased 4 bolts from Halfords. He asked about suitability and the chap behind the counter says "yeah, should be fine".

So, screwed-in the bolts, let off the hoist and starts work. The bolts then fail (shear) and the engine drops to the floor a foot or so, cracking the head and other damage. Oil everywhere.

My questions:
- is this to be expected, bolts aren't designed for this or, should I suspect a flaw in the bolts?
- presumably I can claim costs of damages back from Halfords?
- anyone else experienced an issue like this?

Thanks

Edit:
It would seem that the bolts were M12 coach bolts and the doom-shaped head/s failed (I believe)

 

[sxturbo]

He should have got graded bolts, 8.8 or 10.

Bolts proper bolts should sheer with a number of tonnes on.

The bolts purchased were not up for the job.

 

[RrogerD]

He should have got graded bolts, 8.8 or 10.

Bolts proper bolts should sheer with a number of tonnes on.

The bolts purchased were not up for the job.

Hi, thanks for the reply.
Are you saying that they weren't designed for that purpose? Therefore the error is his in buying the wrong things (notwithstanding the comment from the young lad behind the counter)?

 

[freddiemercurystwin]

Edit:
It would seem that the bolts were M12 coach bolts and the doom-shaped head/s failed (I believe)

Coachbolts, WTF! Sound pretty unsuitable to me, I can't see how Halfords could be liable.

 

[Burnerman]

Coach bolts certainly won't be suitable for this.....can you give us a picture of the disaster, do you think?
John

 

[JohnD]

...The bolts then fail (shear)...

Edit:
It would seem that the bolts were M12 coach bolts and the doom-shaped head/s failed (I believe)

so did the bolts shear? Or did the heads pull off?

M12 is pretty big, it will be interesting to see a photo of the damage.

 

[Stivino]

Are you talking about one of these?

 

[RrogerD]

Are you talking about one of these?

Yes, I think so.
This is it now, hanging from the hoist. You can just about make out the stainless steel coach bolt on the left (bent) and one of the sheered bolts on the right

 

[Stivino]

I assume that the engine was secured with four bolts?

 

[freddiemercurystwin]

Just the wrong type of ungraded bolts, jeez, Halfords are idiots but then most in the know, know not to take advice from suchlike, I would also argue anyone confident with removing engines and suchlike ought to know better.

 

[sxturbo]

Hi, thanks for the reply.
Are you saying that they weren't designed for that purpose? Therefore the error is his in buying the wrong things (notwithstanding the comment from the young lad behind the counter)?

Yes unfortunately the incorrect bolts were purchased.

The other unfortunate thing is the types of people Halfords employ generally tend to know naff all about what they are selling, they will have 1 or 2 which possibly know, but mostly employ spotty teenagers.

The problem is in the wages paid, pay peanuts get monkeys so to speak

 

[sxturbo]

so did the bolts shear? Or did the heads pull off?

M12 is pretty big, it will be interesting to see a photo of the damage.

Appears the head pulled off, but that doesn't really matter as they are machined from a single piece, albeit in this case ungraded steel

 

[RrogerD]

Mmm. Oh dear.
Yes, it was four bolts but as most have said it looks like simply the wrong type used and the heads pulled off.
I'm currently researching as to what the manufacturers say and we'll go from there.
As you say, anyone with experience would know. Unfortunately my 18yr old seems to be finding his experience, the expensive way. Poor lad At least he's got the nonce to be having a go though.

 

[Harry Bloomfield]

This is it now, hanging from the hoist. You can just about make out the stainless steel coach bolt on the left (bent) and one of the sheered bolts on the right

Stainless steel bolts and screws are generally quite soft and easy to shear. I wonder if he might have begun the shear, by tightening the bolts into a blind socket?

I would not trust them to hold anything that heavy. Halfords is a very poor source of technical advice, the advice was worth just what was paid for it.

 

[sxturbo]

Mmm. Oh dear.
Yes, it was four bolts but as most have said it looks like simply the wrong type used and the heads pulled off.
I'm currently researching as to what the manufacturers say and we'll go from there.
As you say, anyone with experience would know. Unfortunately my 18yr old seems to be finding his experience, the expensive way. Poor lad At least he's got the nonce to be having a go though.

As you say it's all part of the learning experience.

We don't all know everything, and kudos to your lad giving it a go.

It's an expensive mistake but such is life, I don't think there is anyone on here or in life that has never made a mistake (despite the poop they post), and I imagine there is quite a few that have made expensive mistakes to, even in their day jobs.

Best he not get too down hearted,