Will be removing at least some heat shielding if not also the headers from a Subaru Outback. The car spent the first 6 years of its life in PA and has an excessive amount of rust on the bolts that need to be removed.

I have a penetrating oil and large breaker bar. Any other tools I need to gather or prep that should be completed before I attempt removal?

2 Answers 2


Sadly, I have a lot of experience with this exactly situation. We're not quite as deep into the Salt Belt as PA but still....

Will be removing at least some heat shielding ...

For this part of the task, the most important tool that you need is replacement bolts. Those little heat shield bolts are the absolute worst: they're cheap metal holding other cheap metal together, they're exposed to every sort of rust-inducing element on the road and they do nothing but cycle from one heat extreme to the other. I'd expect that every single one of yours will snap.

So, plan for it. You'll want a decent metal drill bit (or extractor) to remove any remains of the bolts. If you're "lucky", the nut side of the bolt may have rust welded itself to far side of the shield. You can decide whether it's worth trying to salvage its threads or just chisel it off.

I saw something very similar to what I expect you'll see when I removed my turbo heat shield. Every single one of those little bolts snapped on me. My solution: purchase a turbo blanket and toss out the old heat shield material.

if not also the headers from a Subaru Outback.

Header bolts (and studs) should be much more robust (i.e., grade 8 or better). However, their failure mode is much more annoying and / or destructive. My advice is patience: use penetrating oil, vibration and temperature changes (repeating this cycle many times) before you hulk out on the breaker bar. For example, my little electric impact wrench is unlikely to break off a header stud. However, I was able to snap a motor mount bolt in the block with my breaker bar (admittedly after a great deal of effort).

If things go that badly wrong, you will likely need to drill the bolt out of the block (or have access to a shop or kind soul who will take care of that for you) and fill the newly larger hole with a helicoil.

So, the recommended procedure is:

  1. Patience
  2. Return to step 1
  3. Breaker bar and hope for the best (how did you end up at this step anyway? ;-)
  • Might a Bolt-Out set be a useful addition in step 3 if the bolt is at all rounded off from rusting? Commented Dec 2, 2013 at 3:25
  • @R.., I think you're moving into step 4: "Hell if I know. What do you think we should do?"
    – Bob Cross
    Commented Dec 12, 2013 at 1:39
  • Sometimes you can hammer a 12-point socket from the "other" socket set (metric if standard bolts, standard if metric bolts) onto the rusted and partially rounded-off bolt, but that's a half-baked solution for when you don't have a proper bolt extractor set (looks like sockets with kindof curved cutting edges inside).
    – dannysauer
    Commented Aug 30, 2016 at 20:50

A good fitting single-hex socket is a must. Heating the bolt to red hot in most cases will loosen a rusted exhaust bolt, a sharp rap or two with a hammer will help in some others. If all else fails and the bolts break off in the hole, you are more than likely bound to be taking off the part with the broken bolt in it and drilling and tapping the bolt out. An Old Hands trick to avoid removing parts to drill and tap the part with the broken bolt in a case such as this, is make up a few strips from an aluminium or other metal sheet. Pop-rivet a strip to the heat shield at one end, and attach the other end of the strip to a conveiniant bolt near-by. The heat shield does not carry any weight which makes this a viable option.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .