Stretch Bolts

[Ouphe]

A friend of mine went to the Vdub dealership to pick up some stretch bolts for the right side motor mount (we're replacing his timing belt), and was told by the parts dept. that they have never ordered them and didn't have them in stock. After talking to the service dept., he found out that they have always reused the old bolts and have never had a problem.

I'm due to change my timing belt soon and was wondering if any of you had anything to weigh in about using the old bolts good or bad?

[noR]

Go ahead and use them. It 'should' be fine.

Don't over torque them, and don't crossthread.

I've had my motor hung by 1 bolt on that side; it lasted a few months; then after a drag race it finally snapped.

They're some pretty tough bolts.

[I crossthreaded mine... the most important thing I can think is to try to keep from putting pressure on the bolts as long as possible. jack the motor up to meet the mount, don't just tighten the bolts to bring the motor up.]

But yeah, I wouldn't buy new bolts to change mine again. That doesn't mean it's right or that it's sanctioned by vw. It just means that when I do another timing belt, I'm not going to buy those bolts. From my experience, they're pretty tough.

[Ouphe]

Thanks, I appreciate the help. If those bolts are that strong, I'm not going to worry about replacing them either.

Kindest Regards
Ouphe

[Porkchop]

I had planned to replace mine, but at $5.56 each from World Impex, I'm reconsidering.

Anyone find them any cheaper anywhere?

[hannaco]

Do not know of any cheaper. You can use standard bolts which are cheaper. Just do not tighten them the last 90 degrees like with a stretch bolt.
Just some considerations. The bolt gets it name because it stretches when tightened. The neck will narrow as it stretches. This will weaken the bolt a bit. You might get by with reusing the bolts once, but twice is just asking for problems.

[NYBugman]

You can use the stretch bolts again. I do. I have to take out 2 stretch bolts every time I change my oil because I have a Dieselgeek skidplate. Next time I am going to replace them with some hardened steel bolts, but that's just because I want to, not HAVE to.

[jim]

I don't understand "stretch bolts". When you torque a bolt you're setting it in it's elastic deformation range. This will cause the overall length to be "stretched" but since it's elastic it will return to original length when released.

Is a "stretch bolt" a cheap bolt that is used in it's plastic deformation range? I've seen folks measure the bolt length to ensure it's properly torqued, but this is misleading since the torque decreases when in the plastic deformation state. What gives here?

[jbehm]

I bought mine from ECS tuning for $13.95 for all four.

[hannaco]

NYBugman,
Jim sent you stretch bolts to hold the skid plate in place? I assume that they are the two up front you are talking about. He sent me standard grade 8 bolts with my skid plate.

Jim,
The VW stretch bolts do not "snap" back to the original form factor. They will remain somewhat stretched. Each time they are used, the neck narrows down a bit more until a brittle or work fracture occurs. The diesel may cause this more than a gas motor due to the excessive vibrations.