cjp69

Need help removing exhaust bolts / french locks

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I have a slight exhaust leak at the manifold on my 65 Riviera.  My mechanic friend has been soaking the bolts for a couple of days and is now ready to try and remove them (hopefully without breaking them).  Any tricks to getting the locking tabs off, especially in a tight space, like where the AC parts are?

Thanks in advance, Chris

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Hi Chris,

From previous experience mate I’ve found it’s best to snatch the bolts rather that slowly increasing pressure when undoing the bolts there’s more chance of them snapping undoing them slowly!

Some people advise slightly tightening first? But never I’ve found any benefit mate..

hope this helps. Let us know how things go.

Go luck.

Scuff...

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Got it, Thanks Tom!!!!

 

I will put the answer here as well, in case someone else needs it in the future.

 

Use a long 6 point box end wrench or a long 6 point socket & a ratchet. Give them a "Snap" to break them loose. If their frozen still use a little heat from a propane/map grass torch. Heat well & try again. As rusty as they can get I've never broken one using this method.
I have the french locks in stock if needed.

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Hi Chris,

  I`ve never really had a problem with snapping bolts on the Nailheads. That is not to say it couldnt happen as exhaust fasteners can be problematic in any application. The problem I have most encountered is the size of the bolt head seems to shrink from its original size, likely due to heating and cooling cycles,  promoting rounding of the heads. That is why Tom T is suggesting a 6 point wrench or socket because these are less likely to round the heads versus a 12 point tool. In a pinch I have forced a metric size wrench/socket via a few hammer blows onto the undersized head to get a good bite. Good luck!

  Tom

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A 14mm with the same specs is slightly smaller than 9/16ths & may do the trick. If corroded badly a 13mm in the same specs is slightly larger than 1/2" & mostly will need to be hammered on like Tom above suggested.

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1 hour ago, KongaMan said:

IMHO, a 6-point socket is almost always preferable to a 12-point in any application.

 

I think I almost never use a 12-pt socket. I also wish I had a few more 6-pt wrenches.

 

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To remove any exhaust bolt with a minimum of headache, get yourself some "Mopar Rust Penetrant" (this is a rename of the Mopar heat riser solvent from the 1960s). Soak em for a day or 2. If you can continue driving the car, and you can heat cycle it once or twice, that helps a lot.

 

Rust is brittle, and if you can shock it, it will probably crumble. Never use a 12 point socket for anything, especially this. A small impact gun (or butterfly) can be helpful here. I do not mean the big one you use on wheel lugs, at least not at first. Another thing you can do is hit it with a hammer with some tension in the "unscrew" direction. For instance, with your 6 point socket and a (relatively small) breaker bar, hold some tension and smack the back of the breaker bar (where it makes the corner) with a brass hammer. Keep smacking until you feel the fastener start to turn.

 

If you need to use a metric socket to get a tight fit, then do it. The hammering to get it on there can only help.

 

No matter how you accomplish it, a shock wave is your friend when trying to break up rust. Lots of good advice in this thread so far.

 

 

Edited by Bloo (see edit history)

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