Ok, so I'm pulling the heads on my 93 Z28 and the last thing to do before I finish removing the head bolts is to remove the two "banjo" bolts that hold the steel coolant lines to the back of each of the heads. Now, I tried a 9/16 but it was too small, so then I tried a 5/8 but that was too big. "Ok" I think "Then it's a 19/32 (aka size 15)" So I try a 15 and it ends up almost stripping one of the bolts. So I try it on the other side and find out it's just a hair too big! Dang it! So I'm thinking a 9/32 should be pretty snug and be able to get it, what do ya'll think? Anyone know which size should be used? Any advice to give when removing those lines? Thanks in advance,

 

I've been successful with a 15 mm.

 

19/32 and 15mm are virtually the same, with the 15mm being the tiniest bit smaller. Use a 6 point socket and try "cracking" them loose with pop on the wrench or ratchet handle by a mallet.

 

I took those bolts off yesterday for my heads and cam swap. Yea, they were a s.o.b. Someone thought it would be funny to make them 15 mm when almost everything else on the car is standard. And even using the 15mm it is very possible to strip them since the bolts are so shallow. The Haynes book makes a note of this. Like someone suggested, be sure to use a 6 point or else even if you are using the right size wrench you may strip them. I actually only took off the one on the RHS head and took the other one off the LHS once that head was out. If you leave the pipe on the other head you just have to take off the black sensor or whatever it is that catches the water line first.

 

15mm wrench and hammer worked fine for me.

 

Yea, I tried a 15mm and a rubber mallet, but all it did was start to round off the bolt! So I soaked them last night with some WD40 so hopefully they will be a bit more forgiving when I go back out there and give it a second try.

 

If you need to and have a second hand, you can pull the heads off together, leaving them connected.