W209 Idler Pulley Stripped Threads

[CPR]

Hi guys,

I finally got around to fitting new idler pulleys on my 07 W209 CLK 280, the smooth pulley has gone on fine, but whoever replaced the previous grooved (top) pulley seems to have over tightened it and the replacement will not tighten up fully/snug and appears to be stripped.

While the bolt is not coming out and has had no movement after driving it for a while, I had a chat with my friend who thinks drilling and tapping it with a helicoil would be the best bet and then putting in a new idler pulley, as the bolts are supposed to be one use only and come pre mounted to the pulley.

Has anyone had this previously, or has any thoughts on if this is the best way to go?

Any advice would be appreciated.

Cheers.

 

[Deleted member 131833]

Definitely use helicoils, buy a kit with a drill, tap and inserts for the correct metric screw thread probably a metric coarse thread. Use Zeus chart to determine thread size and pitch of threads.includes a tool to insert and break of the tangs of the helicoil


What is clearance like? Might need right angled drill to open out hole for tap?

 

[CPR]

Great, my friend has an assortment of helicoil kits, so should have the correct size.

Clearance is not too bad, probably around 8-10 inches, so think we might be okay without having to remove fan, etc.

Will probably be next weekend before we get a chance to do it, but will post an update.

Cheers.