MG Car Repair: ignition lock, instrument light, car harness

Question
QUESTION: With the assistance of this site, I am in the process of replacing my ignition lock & key. The original one did not return when starting & the satrter moter would stay engaged. I was instructed to "You must drill straight through the heads with a 3mm drill to a depth of about 8mm.  Then enlarge the hole with a 6mm drill, and the remains of the old head should come off on the drill bit.  Finally you extract the threaded parts, which usually come out easily." The problem is, I still cannot get the darn thing off. I drilled & drilled but it is still on tight - even with a 'little' knudge from a hammer. Any help would be greatly welcomed. Thank you in advance. It is a 1977 MGB

ANSWER: Hi Rick,

You could do it that way but I always found it easier to just use a very small chisel and a small hammer to rotate the head of the screw to unscrew it. The new switch will have new break-off bolts.

Howard

---------- FOLLOW-UP ----------

QUESTION: Thanks,

I did get it off (finally) & put the new part in place. Now I seem to have different wiring. The new 'harness' while it does plug into where the old one came out, leaves 2 wires without a connection. The red #with a fuse set up in it# & a brown wire. I believe both of these are included in the 'plug in' part, but apparently, plug onto a 'phantom' slot. Should I splice them so they are connected to the car?  What other options are there?  Again, it's a 1977 MGB. I could take & send a picture if that would help?  Also, what is your web site address.

Answer
Hi Rick,

The Ignition switch should only have five wires to the harness and only one of the five wires in the harness (car harness) has two wires going to one of the plug connections.

I don't know of any inline fused wire extra. Normally in any MG a red wire is a instrument light wire and a brown wire is always a power wire. So you should test each of these two extra wires by touching the red wire with a powered test light (connect the clip to a power source) then to test the brown wire connect the test light clip to a good ground and touch the brown wire with the probe to see if it is hot. This should at least tell you what function these two extra wires have. If you don't have a diagram of the car let me know and I will post a diagram on my web site for you to copy. Let me know.

Web site http://mg-tri-jag.net

Howard