m8 stretch bolts

[gsc1ugs]

Hi

Anyone know where I can get m8 stretch bolts? my vito 2nd injector is failing the m8 helicoils so I want to put a m8 stretch bolt in save snapping a normal bolt. I know I will have to drill the injector clamp to fit but I feel this is the only way to do this right. Thread is clean with new tap.

 

[hotrodder]

Stretch bolts are typically application specific for various reasons including the point at which they stretch, overall length and grip (shank) length. This is why they cost more than a generic bolt. Easiest solution is the local stealer as it saves loads of time and you're unlikely to save much by wasting time hunting for alternative sources. There won't be many anyway

Here's one alternative source, no idea if they're actually cheaper than MB (loads of 'genuine' stuff on eblag is actually more expensive than from the dealer)... Mercedes Sprinter Vito Diesel Injector CDI Bolt + Seal Genuine MB Part | eBay Also unless the alternative source lists the part number there's no way to know if MB have updated the part in question...

 

[Danny DeVito]

I think you need this sort of thing. ++ BIG-SERT Oversized thread repair kits ++ thread repair kits for oversized holes, previously repaired threads oversized holes
Then you could use an original bolt.

 

[gsc1ugs]

Thxs for replies, the mb part is an m6 bolt they also do m7 but my van have be drilled to m8 but the helicoils are failing, ive tries a normal m8 bolt which is good fit but not stretch hence many posts saying "do not fit a notmal bolt it will snap"

 

[gsc1ugs]

I found this m8 stretch but its too long which is not the problem becaue i can shorten it but the threads not all the way up, do you think an engineering place could thread it most of the way?

http://bit.ly/16Nu0RM

 

[gsc1ugs]

Those time serts look good, better than helicoil but are they long enough? i'm in the uk where would i get them from

 

[mejermy]

Wurth are distributors. Not a cheap option, but miles ahead of Helicoil.

 

[Danny DeVito]

If the M8 hole is clean and not damaged then you could maybe put a timesert in to replace the missing helicoil. The timesert seems to lock in better. It would save having to any further drilling or tapping. Find a Wurth outlet and get a timesert. That will allow use an original bolt also. An ordinary bolt will only snap if you try to toque it like a stretch bolt too. But of course the stretch bolt will keep constant pressure on.

 

[Marku]

ThomasSmithFasteners.com seem to stock just about everything and have no minimum order. Very helpful last year I replaced all the bolts in the 450 engine and they even yellow zinc plated them for me.

 

[E270 Owner]

Use an ordinary m8 bolt with a spring washer.
The bolt wont snap if set at the correct torque.

 

[gsc1ugs]

That sounds like a great idea!!! :bannana: will it work because i'm still looking for an m8 stretch bolt, what torque should i set a normal bolt

 

[gsc1ugs]

those time serts which are m6 seem to be 7.2mm on the outer thread, ive ordered some so i will try