Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Recalcitrant Horn Push Fix

Hi all, this is for anyone who may be suffering a obstinately uncooperative billet Moto-Lita horn push like this:



Monty's example has never functioned with a nice reliable action requiring a firmer than ideal press that didn't always result in the horn sounding, furthermore, unless pressed perfectly in the middle the centre push often had the annoying habit of catching somehow. It would stick in an uneven partially depressed position requiring a further press to return it to its correct rest position, and flush with the outer boss.

If this is sounding familiar to you, I thought it might be helpful share my findings? Firstly, it would seem logical to assume as my horn didn't always sound when pressed, the three rivet looking push pins shown below that complete the circuit needed to be extended, the thinking being the longer the pins are, the more likely it would be they'll make reliable contact with the boss when the push is fully depressed.



Hopefully, you can just make out in the above image that each contact/push pin is installed with a tiny roll-pin down its centre?, I found you can pull on these contact pins with a set up pliers to slide them up their roll-pin, and thus extending them to bring the contact pins closer to the boss.

However, despite the logic of extending the pins this actually made the operation of the horn push worse! I discovered this is because not only must the pins contact the boss, but the sprung loaded mechanism of the horn push itself must also complete an internal circuit. I didn't open up the horn push to view these internal contacts but they're definitely in there, I proved this by touching the removed horn push to the steering wheel boss, the horn would only sound when I fully depressing its sprung centre.

It then made sense to me that the three contract pins have two jobs, obviously, the first being to make contact with the boss when the horn push is depressed. However, less obviously they also act as rivets to hold the sprung mechanism tightly sandwiched together, in my opinion it's a poor design but if the mechanism isn't held firmly sandwiched together, two things happen.

1. The central push button must be pressed deeper into to sprung mechanism to close the contacts of that hidden internal switch

2. The deeper you press the central push button the more likely it is that one or more of the contact pins will extend too far and catch the outer edges of the holes they travel in

Point 2 is why my central horn push button would often catch when depressed, and why the mechanism would stick with the central push held in a cocked-over position until I pressed it again on the opposite edge to free it off.

So, as it turns out the solution was not to extend the three contract pins, but drive them further down their roll-pins to create a tighter sandwich effect, and thus holding the whole mechanism more firmly together. This ensuries the lightest press of the central horn push now creates a reliable connection at the hidden internal switch, it also means the three contact pins never protrude past the edges of their holes so they no longer catch and become hooked up on them.

To drive the three rivet looking contact pins further down their roll-pins, I used a 1/4" drive extension with a small socket fitted to allow the roll-pin to pass up its centre. Placing the horn push on a piece of soft leather to protect it, I then carefully positioned the socket over each contact pin before firmly striking the 1/4" drive extension with a sharp hammer blow.

Driving each contact pin down over its roll-pin compressed the whole horn push mechanism holding it tightly sandwiched together, for the first time since buying Monty I finally have a nice reliable horn push that responds to the lightest press, and no longer catches in its housing. It may seem like a small thing, but for safety you do really do need a horn you can 100% trust will sound when you need to warn another road user or pedestrian of your presence in an emergency situation.

Lastly, with just a very light double tap the vastly improved horn push action finally allows me to deliver that friendly 'Toot Toot' one uses to sound your arrival, or when waking up that snoozing driver holding you up when the traffic lights turn green, this being preferable to an offensive blast that could easily scare and annoy.

I hope the above may prove helpful to anyone suffering a similarly recalcitrant horn push?

Dave.