Bolts - when to renew or not....

[Tonka]

Hi there, I know you knowledgeable people will know the answer to this!

Basically, I have a large project on with another car and several jobs to complete on my Surf. Haynes will often stipulate new bolts are used, but why? I can understand it for stretch bolts, but why in other cases e.g. engine mount bolts, clutch/flywheel bolts?

Is it really necessary?

Cheers!

[popuptoaster]

I usually work on cost of the damage, how easy it is to buy the bolts and difficulty of access if they break to be really honest.

I put loads of new bolts on my Cossie engined Cortina 'cos it seemed silly not to but mostly I just reuse old ones if they are not ancient and look in good nick.

I used to put new wheel studs on anything older than 20 years though after having several snap on me over the years, but they are out in the weather and are almost always over tightened many times over the years.

[Tonka]

I usually work on cost of the damage, how easy it is to buy the bolts and difficulty of access if they break to be really honest.

I put loads of new bolts on my Cossie engined Cortina 'cos it seemed silly not to but mostly I just reuse old ones if they are not ancient and look in good nick.

I used to put new wheel studs on anything older than 20 years though after having several snap on me over the years, but they are out in the weather and are almost always over tightened many times over the years.

Many thanks for your reply, Haynes and the rest though must be applying some sort of logic to this, maybe based on size of bolt and torque it's been under, would be nice to know...

[shokenore]

Hi there, I know you knowledgeable people will know the answer to this!

Basically, I have a large project on with another car and several jobs to complete on my Surf. Haynes will often stipulate new bolts are used, but why? I can understand it for stretch bolts, but why in other cases e.g. engine mount bolts, clutch/flywheel bolts?

Is it really necessary?

Cheers!

Head bolts=always.

Check for damage visible on the thread, also check to see if the bolt has stretched or is corroded.
Would I reuse a dubious bolt on a vital steering, braking or suspension part?
Probably not.
For others common sense should prevail.