Yes, Clean the bolt heads out. I believe the one you're looking for is the #12 tripple square. You can also get one from the Snap On Tools truck. Mine cost about $15. In my mind, the extra $$ are worth it when the Snap On one has a tendency to be a higher quality one. Many people think that buying higher quality is only for longevity. I disagree. It's also for more precise heat treating and milling, and a lower chances of stripping the bolt heads and having a mess to get them out. That's my $.02.

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Too many people tip toe through life, never attempting or doing anything great, hoping to make it safely to death... Bob Proctor

'95 S320 LWB
'87 300SDL
'04 E500 wagon 4matic