MG MGB and MGB GT Tech Talk
My son's 78 B keeps starting / running whether the key is in the ignition or not. The starter continues to turn as the engine is running. It almost ran into the back of my garage the other night. Is this an easy fix or something more involved? Thanks for any help.
Jeff
Sounds to me like either the electrical portion of the ignition switch/steering column lock is toast or a completely worn out mechanical section of the column lock.
Pull the column shroud, four Phillips screws, two on each side, and drop the business end of the switch out usually one tiny set screw on the bottom. Then use a flat screwdriver to operate the electrical section. If it feels good and snap returns to the "run" position after starting then you probably need the mechanical lock section.
There is another current thread below dealing with this.
Removal of the column lock is easy and there are several methods.
I prefer to use a hammer and awl or sharp punch to catch the sheered-off bolts from the top and walk them out. When you go back together you can use normal cap screws (bolts). Other folks like to use a Dremel tool to cut screwdriver slots in the rounded heads and that is certainly an option.
Jack
I've seen starters that would "catch" in the teeth of the flywheel and remain there, so that the starter gear would not retract. I agree with Jack on this one, though.
Try removing the white/brown wire from the starter relay. The starter relay is to the left of the
fusebox as you face the engine bay. Do you have a multimeter or a test light?
If removing the w/n wire stops the starter check the voltage on the white/red wire on
the starter relay with the ignition switch off. There shouldn't be anything there. If you
have voltage go to the ignition switch as Jack suggested.
Clifton
Yep, the old Bendix inertia style pinions would do that a lot, but the pre-engaged ones don't seem to screw up stuff as often.
If all else fails pull the starter or eat a bar of soap, which ever is more appealing, and have a look at the back sides of the ring gear. You will have to rotate the engine tooth by tooth with a screwdriver, but you would be looking for some really gnarly teeth that might have been chewed up because of someone trying to start the engine while it was already running.
Jack
Had the same problem, changed the lock and cylinder and switch and everything worked again.
Jack, I've got to give credit where it's due here by the way. Your article in the library helped me get the &^&^%%^(*() lock assembly out of my car.
The hammer and awl thing didn't work out for me, but those bolts were really tight. Careful use of a dremel let me cut slots for a flat-blade screwdriver in the sheer bolts. If you do need to use the Dremel, Jeff, you run a slight risk of cutting slots into the lock body as well as the sheer bolts. Mechanically, that's completely irrelevant but cosmetically it looks bad. You can cut the slots in the bolts without damaging the surround.
On this topic, I am having the same problem with my '71 GT. My ignition switch itself seems to be fine, but the metal "lock" that turns the switch broke. This is the piece that is the adapter between the key cylinder and the ignition switch.
You can see pictures of the failed part here:
http://picasaweb.google.com/WillShoots/1971MGBGT#
Does anybody have one of these leftover from a lock replacement or anything like that? I'm trying to avoid drilling out my original lock assembly, so I'd like to buy just this piece.
Thanks!
Will
'71 MGB GT
