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MG MGB Technical - Solenoid going?

My 67 BGT has started to have a little issue. When I turn the key I get a click coming from the area where the solenoid is. The key is also sticking a bit so prior to buying parts that may or may not be going bad, I thought I would get input from the group.

After a few on/off with the key, the starter kicks in.

I am figuring to totally clean the connections on the solenoid and also do the same on the battery as well as checking the connections on the key switch are tight. This will be part of my preparations for my across the US trip at the end of the month. I know I can jump across the solenoid if it fails to switch on, so I don't think if it did fail it would slow me down much.

Bruce Cunha

Bruce - If you have an original solenoid, there should be a rubber cover on the opposite end from the terminals. You can push that rubber cover, manually engaging the contacts. If that doesn't work of takes a lot of pressure on the rubber cover, I would suggest that you just get a new solenoid - they aren't that expensive to have to put up with any guff from them. Cheers - Dave
D W DuBois

Bruce,
for the key sticking try cleaning and polish up the key a little (with something that's a light abrasive rather than a liquid type polish)

and for the ignition barrel try a little dry graphite, works a treat, you can buy a small bottle and use in all other locks on car and home or make your own with the right type of pencil

don't forget the tip of alternating the use of your spare keys so that you know where they are and that they work the locks easily (and to help to even out wear a little) as I'd guess you'll want to know where your spare keys are and that they all work well when you're on your long trip
Nigel Atkins

Thanks for the reminder Dave. The solenoid button is one of the interesting little items on the MGB.


Nigel another great tip I was going to use some electrical contact cleaner in the key slot, but graphite is a better idea. I have a bottle of this so, I can put it to good use.
Bruce Cunha

Bruce,
if you've got a separate solenoid then do check the bottom foot, screws/bolts and body panel it's attached to are all clean and free of rust and that there's good electrical contact for the solenoid to earth through it's attachment to the panel

clean up and protect with something like copper grease or electrical contact grease
Nigel Atkins

Bruce, these solenoids rarely go bad. I only replaced the one on my '67 B due to it having become soaked in oil after a line burst. I still even have the original ignition switch and both sets of keys it came from the factory with. Check all of your connections for cleanliness and tightness. RAY
rjm RAY

I am thinking that also Ray. Typically if a solenoid goes bad, it fails, this one is intermittent so I am thinking a bad connection.

Nigel, I was going to ask about if a dielectric grease was a good idea on the connections. I have used it for things like spark plug boots, but typically just clean/buff the brass connectors for things like the solenoid and starter motor connections.
Bruce Cunha

Bruce,
a dielectric grease is a barrier so no as it's doing the opposite to what you want it to on connections

personally I prefer well made HT lead set to having to supplement its sealing but in a way you could say that adding a contact grease to cleaned connections is a belt and braces approach but I'm sure you've seen hidden gunked up connections on your car so if you can help to prevent them it must be a good idea

some say not to use anything with silicone in as a contract grease

here's just an example of a contact lube, see two thirds of the way down the page for car use - http://contralube.com/contralube-770/
Nigel Atkins

If you have the remote solenoid see if you have 12v on the stud that has the motor cable connected to it when you get the click but not the crank. If not, make sure you still have 12v on the battery cable stud. If not, the connection back towards the battery is bad. If you have 12v on the battery cable stud but not the motor cable stud, the solenoid is at fault. If you have 12v on both studs check the voltage is on the starter cable lug as well, and on the motor stud. That will tell you whether it is connections or motor.
Paul Hunt

Thought I would post an update.

This weekend I went through the whole starting system. Starting with the battery, all cables and terminals were cleaned. Next took off the wires on the solenoid and cleaned all the terminals and connectors. I did find some play in the spade connector for the brown wire. Just a little tightening of the inner nut.

Took off the starter wire and cleaned the terminal and the connector. I did note a little play in the starter motor body. Attachment bolts were tight, and I could not get the threaded rods that go through the motor to tighten up at all.

Also added a small amount of graphite to the key and worked it to get the powder around in the switch.

After all this, car started perfectly. Today I get in and Click. Turned it of and tried again and it started right up.

I note that the solenoid is like $22 from Moss, so will probably just replace that.

Can;t get it to fail enough for the tests that Paul suggested, but I am getting a good 12 V to the solenoid and from the solenoid to the starter during cranking.
Bruce Cunha

The trick is to position a voltmeter in the cabin where you can see it, and semi-permanently connect it to each test-point in turn until you get the fault, then based on the result of that decide where it has to be connected next, and so progressively isolate the fault.
Paul Hunt

Bruce,
you don't want a lot of graphite but I think you were being a bit too careful with it by putting a little on the key to transfer it to the lock

I've got a small 16 gram plastic puffer bottle of it and gave my ignition lock three good puffs as I inserted the key in three stages, I'd suggest you do the same and on the doors, hatch, glovebox locks

I gave my home front door lock about 5 squeezes of the bottle - just wipe away the excess - that made an amazing difference to it's easy of use

I went round doing other locks and still have half of the 16 gram bottle left

Nigel Atkins

Nigel.

That is pretty close to what I did. I have a older graphite bottle with a blunted needle on it. Great for getting into locks.

Paul. Got it. I can set that up fairly easily

PS. Did it again today, but again, one click, turned the key off and then tried again and it started right up.
Bruce Cunha

Bruce, I had exactly the same symptoms on my BV8, turn key - Click, turn again - starts. Changing the solenoid cured it completely.
Mike Howlett

This thread was discussed between 08/07/2014 and 18/07/2014

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