Yes, the nut between the big cable and the solenoid is to put a wrench on so that the cable is tightened between the two nuts, and not just applying torque against the solenoid body.

Replaced the solenoid with the 75 Mustang Solenoid $11.00 and some change (with military discount at Oreilly) it starts now  

just have to be careful not to over torque it.

Heres the old one

Robin, I had one of the old cylindrical (OEM) solenoids on the GT6.  It eventually died and I did not see a way to open it for repairs.  I may have been the one to tell you about the circlip coming off the inside of the shaft in the repro solenoids.Like you, I have had a couple of those "modern" repros of the pushbutton solenoid fail so I won't use them anymore.  BTW, the GT6 has been using the Mustang solenoid for several years now.  When you need one in a hurry like we did it was a very convenient swap.

The uglier "brick" Lucas solenoids however, can be opened up by drilling out the rivets and replacing them with machine screws during reassembly.  You can easily use those as pushbutton type solenoids by jumpering between the terminal with the white/red wire and the terminal with all the brown wires.  It's quick and easy.  When those "fail" it typically is burned copper contacts which can be sanded flat and placed back into service... unlike the damaged circlip and circlip groove in the cylindrical solenoid.

It is dangerous I think. So many times I've accidentally pushed that while I'm working or cleaning in the engine.

Yep, I've eaten two of the crappy "can shaped" push button solenoids shown in your picture. One of 'em didn't even last a month.

I understand that there's a circlip inside that fails and you lose both the standard solenoid operation and the pushbutton.

Probably easiest to get the Mustang one. Or, our host carries this one:
 www.minimania.com/part/SRB335/Starter-Solenoid-78-On-Mini--Mini-Cooper

It looks just like the old pushbutton solenoid but it's just a nub of plastic instead of the rubber button.
You lose the pushbutton feature but, really, how often do you want to run yerself over when you forget the car is in gear?

Found this old picture maybe February or March this year and I zoomed it in with my phone. But it's pretty much the same cosmetic condition.

I guess first time it's impressive maybe not the second time but yeah let me pull it and I'll take a pic to see if this is the one you wanted. I'm planning on getting a new one anyway. maybe a later type. Here's my email Zippy: [email protected] I don't know anyone that rebuild these In my area. 

If you do have the early solenoid with the push button, don't toss it out. I'm told it can be opened up and rebuilt. If you don't want it, I would be happy to pay postage.

And, whatever you do, don't be tempted by the "can shaped" solenoid with the pushbutton currently being sold by the usual Mini shops. In my experience, it'll leave you in the same situation in short order.

Edit: If it's available, park on a hill and bump start it until you get this sorted. No, it doesn't impress the girls so much but, you're on your way with far less drama.....

This happened to me today at the school parking lot around 12 noon. Tried to start it.. Nothing except a tiny "click" sound. Pulled the multimeter and checked the battery and I got 12.75 V.. Then checked the hot side of the starter solenoid to see if it's getting the proper 12 and it still says 12.75 V. Tapped the starter solenoid a few times with a small wrench and still nothing. Not turning over.. It happened toe a few times before but this time it just won't get unstuck. (Mine is the push button solenoid type)

Turned the gear to neutral, turned the ignition on with key (ignition light on), got out of the car and jumped the starter with a screw driver. It started. 

Chicks at school were so impressed

so what causes it to get stuck? Worn out? Intermittent connection? Too many wires hooked up to the starter solenoid? Wires are torqued too tight to it? How do I check if I have enough wires hooked up to it? 

But anyway, I'm bringing a bigger screw driver tomorrow so more chicks can see.

What part of the first post "i tried jump starting it and nothing" don't you understand.

Please don't disrupt this thread with you ignorant comments, you have already done enough damage here.

That's probably not a rubber button.  I think those were only on the early cylindrical solenoids.

Dmulder, did you try to measure the voltage on the white/red wire when the key was held in the start position?  If not, make that test before buying a new solenoid.  If there is no voltage on the white/red when the key is turned to start... the problem is not the solenoid but the wire or ignition switch.

If you determine that it really is the solenoid and need the car quickly... go to the local parts store and buy a solenoid for a 1975 Ford Mustang.  You'll have to modify the wire connections a bit but it's not hard.

EDIT:  The picture below shows the pin out of the Ford solenoid.  The small threaded post labeled "S" gets the white/red wire.  The white/yellow goes on the "I" terminal.  

The solenoid in your photo appears to have a black rubber button between the threaded posts. Push it - the early solenoids like that had a button there to close the inner contacts manually. If it works, it is just like shorting the two big terminals. If not, the contacts inside may have worn out.

I tested like you said. Even when turning the key I get no voltage on the threaded post going to the starter. I did test by jumping and the starter ramps up. I hear no clicking on the solenoid. My guess is the solenoid. Just orders a new one. Means I'm riding my bike for the week

I want my advice to be final and executory...

ok,so you parked your mini car for the weekend, it means that is 2+ days, and anything can happen in two days right?...

so ,you turn the key on and you heard  the electronic pump priming, radio, lights etc. works... i tell you what,  a battery with 10.5volts left in it can prime an electronic fuel pump, turn on lights BUT cannot ,..again, it cannot turn the car starter. , car starter require at least 12.5 rockin' volt to make it turn over the engine... i suspect you have a low voltage battery, might have partially discharged during the efin' weekend. 

check the voltage of your battery/ charge it, if it still don't work after charging,then the solenoid is the next culprit/  or worst , the starter must have shorted(not likely but the possibility cannot be discounted).

What you are showing in your picture is the starter solenoid that I mentioned in previous posts.  While it is a relay, it isn't called that.  Later cars with the pre-engaged starter motors have a separate component called a starter relay so it would be confusing to call the inertia starter solenoid a relay.

Your picture orientation changes depending on whether you are looking at the picture in the embedded link or open it in an external viewer.  Therefore, I will refer to the orientation a bit differently than "left" and "right".  You SHOULD have 12V on the threaded post with all the brown wires.  You should NOT have any measurable voltage on the threaded post next to the inner wing UNTIL you turn and hold the key to the start position.

Repeating a bit of what I said earlier, get a helper and measure a couple of voltages.  
Engine off, key out, look for 12V between a bare metal spot on the engine/chassis and the solenoid post with all the brown wires.  If you don't find 12V on that terminal... nothing in the car will work.  Nothing.
There are two small spade terminals on the starter solenoid (spades without brown wires).  One will have a white/red wire, the other will have a white/yellow wire.  Neither will have measurable voltage between them and earth with the key out of the ignition.  Have an assistant turn the key to the start position and hold it there while you measure between each spade lug and earth.  When your assistant turns the key you should hear a "click" as the solenoid contacts close.  Both white/red and white/yellow wires should measure 12V.  If the white/red wire does not measure 12V with the key held in the start position, you have a problem with that wire or the ignition switch.  Don't worry about the white/yellow wire at this time.

If the white/red does have 12V on it with the key in the start position, have your assistant release the key.  Use a pair of pliers or a heavy screwdriver to bridge between the two threaded posts on the solenoid.  If the starter motor spins up, then you know the starter is good and the problem is with the solenoid.  Make sure the solenoid has a good earth connection and try again to start the car.  If making sure the solenoid earth connection is good and clean does not address this problem, try a replacement solenoid.

So I think it is the relay that is bad. Do these go bad?

So I think the power block is bad. I have voltage on the left side (when looking at it) but none on the right. 

I think a '76 would still have the inertia starter.  Find the starter motor on the engine and follow the large cable back from it to the starter solenoid.  The solenoid can be mounted a few different places.  You will easily identify it.  There will be a large cable coming from the back of the car connected to one of its threaded terminals.  That terminal will also have a bunch of brown wires connected to it.  The other threaded terminal will have cable which is connected to the starter motor.  There will be a small white/red wire connected to a spade terminal on the solenoid.

The white/red wire is the trigger supply for the solenoid.  It comes from the ignition switch.  If you have a multimeter, connect it between the white/red wire terminal and have an assistant turn the key to the start position.  The meter should show about 12V.  If it does not, that says the white/red wire is broken, disconnected at the ignition switch, or the ignition switch has failed.

The suggestions earlier about jumpering across the two threaded posts on the terminal will tell you if the starter motor itsel is OK.  A screwdriver or pair of pliers bridging the two threaded solenoid terminals is going to pass battery current to the starter without using the solenoid contacts.  If the starter motor spins, at least you know it is OK.

If you have 12V on the white/red wire when the key is in start and the starter motor spins when the threaded terminals are jumpered, that says the internal contacts of the solenoid have probably failed.

To get an idea what some of these things look like, visit our hosts parts/inventory pages.  Search for items like:  solenoid, starter motor, etc. 

Doug, 

It is a 76 with an 848/850 in it. Brand new to this game so identifying is a little difficult for me. I didn't hear anything. No click no soft or loud sound nothing. In the 10 minutes I had I found I had power to the coil and coming from the coil. Checking what appears to be a power block next. 

One of the smaller wires (white/red maybe) that go to the starter is the ignition source, it only energizes when the switch is in the crank position. Sometimes it is just a connection issue if it is not getting current you need to back track it to the switch, sometimes it is easier to run a seperate wire rather than splitting the harness to find the problem. Sometimes the starter engages and sticks, if so you need to "rock" the car in 2nd or 3rd gear to disengage it you should hear a clunk when this happens.

Follow Doug's instructions to figure out the issue you have.