TR2/3/3A Starter Solenoid Push Button

[Perrymip]

I've used this luxurious feature for all kind of things including adjusting valve lash, setting points gap, moving the engine tp TDC, and so on. But twice in my life that solenoid has stuck ON. This is an unpleasant moment, the starter racing on and on, all one's first first instincts unproductive, then, finally, wrenching free the battery cable to shut everything off.

My first instinct: replace the solenoid. The reason for this is that I feel so snake-bit after the failure, that I really don't want to lean over and press that button again. So I put a new one in. But the "new' ones are not the "old" ones, beefy and hefty pieces of Lucas engineering. And I recently had a "new" one commit this same ugly failure.

Any advice, other than avoid using the solenoid button?

 

[dklawson]

I feel your pain. The modern, reproduction pushbutton solenoids that I have bought (3 of them) were all junk. They were bought at different times so I cannot blame them for all being from one bad production batch/lot. Inside the pushbutton solenoid is a pushrod that moves the contacts. On the pushrod are a couple of circlips. The circlips do not stay in the grooves very long and when they come out you either have a solenoid that doesn't work or one that sticks on. This
failure does not occur with the pushbutton feature... only with normal use of the key start.

My advice takes two approaches. If you have an original solenoid... keep it but don't use the pushbutton. You can easily make a little jumper wire and slip it into/under one of the brown wires spade terminals on the solenoid. Tap (tap not hold) the other end of that short jumper against the solenoid terminal with the white/red wire. That will energize the solenoid just like the pushbutton so you can bump the engine over on the starter. Remove or tape off that jumper wire when not in use.

The second approach is to say that if you are into originality and no longer have an original solenoid... you are stuck. For the "look" you need the reproduction or a functioning original part. Just be mentally prepared for the failures I mentioned above if you select the reproduction. If you are not concerned about the original look, fit the later "brick" shaped Lucas solenoid or one from an early 1970s Mustang and use the jumper wire in place of the pushbutton.

I wish there were quality reproductions out there. I would like to have them on both the GT6 and the Mini.

 

[Born_Loser]

I have used the button hundreds of times, never giving it a second thought. One of my chokes occasionally hangs just a bit, and I usually raise the bonnet for a cold start - just to double check the chokes seat. Since the bonnet is up anyways, that's usually how I cold start the car. Better re-think that!

 

[Geo Hahn]

Mine has stuck on twice - both with near disastrous results.

First time I had the car in 4th and pushing it backwards to free a jammed starter. Well it freed alright, then I found out that the solenoid was on when the car began lurching forward running over my right foot and towards a block wall about 4' in front of it. Got the ground cable off just in time.

Second time the solenoid sticking coincided with a short in the starter that melted the battery cable (and created a lot of acrid smoke) before I could pull the very hot ground cable off.

Sorry, I don't have a good solution. I like the button feature so much I added a button in a discreet location to my other British car that did not come with a separate solenoid. I suppose that would be one alternative.

 

[dklawson]

I like the button feature so much I added a button in a discreet location to my other British car that did not come with a separate solenoid. I suppose that would be one alternative.

That is similar to the jumper wire method that I mentioned. I like the idea of a discrete switch... much cleaner than a temporary jumper.

 

[Geo Hahn]

... I like the idea of a discrete switch... much cleaner than a temporary jumper.

Mine happens to be the fast idle test button from a '71 Fiat, though any sturdy push button should suit.

That piece of fuel hose over the end is to prevent accidental use (as in 'Ooh, I wonder what this does?').

 

[Perrymip]

Excellent and much appreciated suggestions. I've dug out my original solenoid, and will either use it with a jumper or I'll install an external switch, likely not so elegant as Geo's. I too have always used the button solenoid for under-the-hood starts and thought this a wonderful feature.

The failed "new" one I'll attempt to autopsy.

This is not the first time I'm glad to have held on to old parts, although this does get to be a lot of boxes, very loosely catalogued.

 

[dklawson]

This is not the first time I'm glad to have held on to old parts, although this does get to be a lot of boxes, very loosely catalogued.

When people ask me why I store so much junk I have to remind them that I own older British cars and that there is an unwritten code that you throw away "nothing". I do draw the line and throw out old bits of burned wire, rotten rubber parts, and any old brake seals. My children will hate going through the boxes and shelves after I die.

EDIT: George, that bit of fuel hose is a great idea !

 

[Andrew Mace]

Never had one of these stick myself. I wonder, though, if just spraying around under the rubber button with electrical contact cleaner (or maybe even WD-40?) might free up a stubborn one? Just guessing here, as I haven't tried it....

 

[Perrymip]

spraying around under the rubber button

By the time I got the failed one off it seemed just fine. The plunger went in smoothly and seemed to return the same. And everything tested, from the outside, with a meter, okay.

The issue is that once this occurs, one loses confidence, no matter how many hundreds of times it's worked just fine.

 

[martx-5]

My original push button relay was toast, so I bought one from Moss. It lasted about a year and then stuck on when I was checking the valve clearances. Fortunately, I never really tighten down the ground cable and was able to pull it off. Then it happened once when starting it from inside the car. Fortunately, since it was the first fire up of the season, I had the bonnet up and was able to pull the ground cable off in a reasonable amount of time. I immediately went down to the FLAPS and bought a Ford starter relay. Haven't had a problem in over four years now...better knock on wood just in case. :wink-new:

I do like the idea of a starter button under the bonnet instead of using a piece of wire or screwdriver.

 

[TR3TR6]

Perry, I've never had the solenoid stick on my car, but I installed a battery cut-off switch on the battery post which is within easy reach of the solenoid.