Dogbone mount/gearbox mount thread gone! Please read very urgent.

[MattyV6]

Ive not got a clue what the actual cost was for the re tap because i had other stuff done too but they just re tapped it 

[Prawny]

I'm sorry, but retapping it to a bigger thread is NOT a better job. I don't care what anyone tells you, they're wrong.

A helicoil is a stainless steel threaded insert, you drill out the dead alloy thread, and cut in a larger deeper thread, into which the stainless insert screws and locks. This is secured into the alloy box casing in exactly the same way as a bigger bolt would be, by a bigger thread.

It won't pull out, ever, and it retains the correct sized thread and means the dogbone doesn't need drilling out.

Generally speaking, given an M12 alloy thread, or an M12 helicoil into an alloy housing, the helicoiled M12 will be stronger.

Many people using alloy components will drill out the stock threads and fit helicoils before even using them, to reduce the risk of threading the soft alloy threads.

Please don't go paying someone £100 to do this job. it's £25 for a helicoil kit with 10 inserts or more in the box. If you're taking it somewhere to have the work done, they'll already have the kit, so the parts cost to them is about 50p for the insert, and a MAX is 30 minutes labour.

I could do this work on my drive in less than 15 minutes with very basic tools. please don't get ripped off mate.

[Prawny]

and for reference, M12 was from memory. Just checked and the dogbone bolts in the box are both M10 x 1.5 thread. M12 is the engine mounts, which I've also helicoiled

[Dommy GTi]

Okay, well I've just seen your comment P and I paid £90 for some sort of machine that uses a long drill for something? And then a short one to have a permanent thread replacing, but I got the car and it feels so much better, no more tractor shaking haha.

Thanks everyone for replies and advise, at least I know now for future reference.

Cheers.

Dom

[Wayne]

Ouch £90 was a lot to sort the problem.

[Prawny]

Please don't go paying someone £100 to do this job. it's £25 for a helicoil kit with 10 inserts or more in the box. If you're taking it somewhere to have the work done, they'll already have the kit, so the parts cost to them is about 50p for the insert, and a MAX is 30 minutes labour.

I could do this work on my drive in less than 15 minutes with very basic tools. please don't get ripped off mate.

I'm definitely in the wrong trade if someone charged £90 for this, even at £40 per hour they're still claiming almost 2 hours for a 20 minute job :S