Renault Assisted Gear Changers
Over the years Renault have used a number of assisted or automatic gear change systems with a varying amount of success. I run an early assisted gear change 750 and have been partially helping on a Caravelle with a slightly more sophisticated assisted system. Although in that case the decision was taken to rip it out, in doing it, a number of documents came to light that are of interest and also some differences in approach.
Maybe it is about time to pen what I have found out and hopefully in reading it, others may contribute, recommendations, corrections or alternatives as there is no way that all I write will be correct or practical. I hope to break it down into 4 sections special to the particular methods – Electric Clutch, Powder Clutch, torque convertor and “flappy paddle”. I must also acknowledge the input of The Floride and Caravelle Club of France and most importantly Jaeger in France and America (where these were more popular) for giving me a copy of the original in factory repair manual and permission to reference it. This has been used alongside Renault’s own repair manuals I have.
I will start close to the beginning (I say close because even pre war Louis had various methods for changing gear, some assisted) with the Ferlec clutch. This clutch was made by Ferodo and was of a simple electromagnetic type. It is often confused with the later Jaeger powder clutch and even initially I was surprised at how many referred to the push button system as a Ferlec, when in fact Ferodo had no involvement in it.
All a Ferlec clutch is – in basic terms – is a normal manual gear box, with a normal floor mounted gear lever. The drive still changes gear. The only bit that changes, is that the clutch plate (which is still round and covered in a friction material) is squeezed by an electromagnet rather than the springs of the clutch pressure plate and altering the current changes the pressure on the plate, exactly as your foot on the pedal changes the pressure.
The only clever bit is that there are a number of switches and variable resistors that alter the pressure dependent on revs and gear lever position and a switch to lock it in for bump starts and going down hill. Oddly the more this clutch wears the less it slips as the “pressure” disc is allowed to move closer to the magnet.
Looking at it item by item. The gearlever is a conventional lever with a rod connecting it in the normal way to the standard gearbox (although the input shaft on the Ferlec is different and there is no clutch fork or pivot). All it has in it is a switch at the base so that when it is touched, the clutch disengages. This allows you to select gears without crunching.
Between the engine and the gearbox you have a device that at fist glance does not look a million miles away from a standard clutch. You still have a disc with splines on the gearbox input shaft, although in the case of the Ferlec the “fibre material” is a brass/bronze based material rather than asbestos or cashew nuts. One side of this is a metal “contact disc” and the other side the magnet. The whole assembly is bolted to a “conventional” flywheel. All be it slightly different in design.
On the bell housing there are 2 brushes that run on 2 rings on the clutch plate. When current is supplied to one of these, the magnet is charged and the whole assembly clamps together. This is very similar to the aircon clutch in a modern car. When you release it, the pressure comes off.
The current to these brushes comes from one of 2 routes. Normally the dynamo (which means the engine must be running) supplies a variable resistor system attached to the accelerator rod. This is not a perfect variable as it actually has a number of segments, each with a fixed different resistance. As you accelerate, an arm moves to the next segment and the current goes through a different resistor. The more you accelerate the more current you get and the more the clutch is squeezed.
When the engine is not running, there is a switch under the dash (with a bright warning light) that locks the clutch in. This is used if you want to bump start or in certain other cases. The problem here is none of the other devices switch it off so you can’t change gear without a lot of luck. It is also used if you coast down a hill because in a normal car as you go downhill you can lift of the accelerator and the engine brakes the car, on a Ferlec if you lift off it free wheels. The switch locks the clutch back in.
The tricky bit is setting up the segments to engage at the right point in relation to the speed of the engine. Especially as it differs from cold to hot, also at low revs, the clutch is actually in a partial slip mode. This makes it quite hard to drive onto MOT ramps as the slope combined with the low speed leads to slip, if you rev up
you go to fast but can’t slip the clutch.
The other difficulty is the more it wears the tighter it gets. It has shims you add and remove to adjust it but at some point it needs a reline and these are not like clutch plates you can just send to your local relining specialist. It’s why mine got a lot of trailering until I got a full spare unit as backup.
The most common issue with the Ferlec is the need to make adjustments to both the carb for smooth running and then the resistor box to ensure the correct segment is selected. After that you have the normal brush wear, although these are fairly easy to access and the wear in the plate which will finally lead to the need to change the shims.
There is also the danger aspect, a mere lift off the pedal approaching a bend or a roundabout can be catastrophic as the clutch disengages, as the take up is gradual then you need to be very smart on the pedal or you can see yourself freewheeling round roundabouts and it was not unknown for these cars to come out of bends backwards as the clutch bit in and the back end whipped round.
If it is set well it is perfectly possible to sit at junctions or lights and hold it on the brake, and like a normal automatic take off gently. It’s also perfectly possible when it is not set well to depart like a demented kangaroo. In fact there is a nice little story I have got from America about a youth who bought one that I have included here.
I was a senior in high school with a driver’s license, and like others my age, I regularly pestered my father for the keys to the family car. Because of that, and because I would likely need a car to go to college following graduation (or go to work, if I wasn’t able to get into college), my parents decided to help me buy a car. The mere thought of having my very own car stripped me of whatever miniscule amount of reason I possessed as a typical dipshit seventeen-year old scouring the local newspaper for a reasonably priced used car. The year was (and I really hate to date myself) 1964.
One ad in the paper caught my eye. Someone was selling a 1960 Renault Dauphine (Yes, a
farookin’ French car) for what seemed like a ridiculously little amount of money. In fact, it wasn’t much more than my friends had paid for cars four to five years older than that. I mentioned it to my father, who
counselled, “I don’t know, Son. I’m not crazy about foreign cars.”
Naturally, I didn’t listen to him and badgered him to “just go look at it with me, PLEASE?”
When we arrived at the address given in the paper, it was easy to spot the car parked in the street, as Renaults were not at all common then (and thankfully, now either). It was a little white car that looked sort of like this. I say “sort of,” because what really caught my eye (which obviously, by this time, was not connected to my brain) about this particular car were the two blue racing stripes that ran longitudinally across the car from the front bumper, over the hood, roof and trunk, to the left of the center line, all the way to the rear bumper.
Those stripes turned the rather non-descript (even dumb looking) French piss pot car into something unique. My underdeveloped seventeen year-old brain saw myself driving up and down the main drag in town in a car that would be instantly recognizable by everyone. I wanted that car, and it was priced right.
We met the owner and he showed us the interior. Again, my emotions and desire for the car completely overpowered my reason, when I saw that there was ONE seatbelt in the car – on the driver’s side. I knew that cars (back then) did not come “stock” with seatbelts and that, if you wanted seatbelts, you went to a place like Midas Muffler to have them installed. And, if you were going to RACE the car, you only needed one seatbelt – on the driver’s side. Given the presence of the racing stripes and the single seat belt, one didn’t have to be Sherlock Holmes to know that the car had been raced. I knew it, as did my dad, as evidenced by his trying to talk me out of my brainlessness.
Forging ahead and completely ignoring the obvious Red Flags (and my father’s advice to “let this one go”), I looked closer at the interior and saw a stick shift on the floor, but noticed that there was NO CLUTCH. I asked the owner about that, and he told me that the car was equipped with the then state-of-the-art “FERLEC clutch.” The FERLEC clutch was an electro-mechanical affair that permitted one to change gears without the need of a clutch. All you had to do was press down on the stick and shift the car as you would a normal stick shift. I thought that this was absolutely fantastic, but my father was, to say the least, highly
skeptical. (“Jim, I never heard of such a thing, and it sounds like a horseshit idea to me.”) My father’s advice went in one ear, passed through my car-mush inside my head and went out the other ear.
We bought the car.
What a disaster.
Proper use of the infamous FERLEC clutch required that when the car was stopped, you had to press down on the shift and put the car in neutral. The problem was that finding “neutral” was not easy and, because of the idiotic design of the electric clutch, finding neutral was often impossible. When you thought the car was in neutral, it really wasn’t, and it would stall (exactly as a standard shift car would if you stopped and did not engage the clutch). Once the car stalled, you had to “find” neutral, but knowing what gear the car was in was always a crapshoot. Not knowing what gear the car was in became a huge problem when trying to re-start the car after one of its episodes of stalling. If the car was still in gear, it would lurch when the ignition was engaged. If you turned out to be in first gear, the car lurched forward. If you were in reverse, the car lurched backwards.
So, one night, I was “showing off” my spiffy car with the racing stripe to a buddy of mine. We had successfully completed a couple passes up and down the main drag. On about the third pass, we stopped for a light in the center of town. This time, the infamous FERLEC clutch failed to work properly and when I put the car in what felt like neutral, the car stalled.
As I fiddled with the shift to make sure I was in neutral, the light turned green, and the guy in the car behind me beeped his horn for me to get moving. I turned the key in the ignition, and BAM!!! My car flew backwards into the car behind me. My friend in the passenger seat started to laugh his ass off, but I could tell from looking in the rearview mirror that the guy behind me was clearly surprised and not at all amused.
Anxious to simply get away from the embarrassing scene, I fiddled again with the stick shift and again turned the ignition to re-start the car, and BAM!!! I flew backwards into the guy’s car a second time.
By now, I was shit scared and sweating bullets, as I saw the guy in the rearview mirror, seriously pissed and opening his car door to get out and kick my ass. However, he abruptly changed his mind when BAM!!! I hit the son of a bitch a THIRD TIME! He must have concluded that I had to be some kind of homicidal nut, because he hopped back in his car, flipped a U turn and drove like hell the other way.
It was a basket case, but my friend in the front seat damned near died laughing.
The next day, my father followed me to the dealer a few towns away (keeping a safe distance behind me at intersections). At the dealer an honest mechanic took us aside and told us that the FERLEC clutch was a worthless piece of shit design failure and that Renault stopped putting them in cars after that model year. Fixing the thing was expensive and next to impossible. He recommended spending some serious money to install a regular transmission and clutch.
We placed a “For Sale” ad in the local paper the next day.
I should have listened to my father in the first place. It wasn’t the first time I told myself that, nor would it be the last
Does it make for easy driving, not really. It’s also less tolerant. If a dynamo goes on a “normal” car you can disconnect it and get a few miles on the battery. If the dynamo goes on mine the clutch goes too, you can use the little switch but it is like driving with a broken clutch cable which is not fun. Especially starting off (cranking on a 6v starter in gear is just not viable). It’s also just not automatic. The car does not change gear for you, it is really just an assisted clutch. Whilst aimed a lot at the American market, who struggle when presented with 3 pedals, and of course those who need perhaps a 2 pedal solution, its market share was not great. Oddly in the 50s it was probably exempt import duty if you were disabled as it is technically a disability aid.
It lasted from its introduction in 1955 to the Dauphine era and made it to a 12V version but its days were numbered when Jaeger came along with the next stage (shared with Peugeot) the powder magnetic coupling. The clutch itself still has uses in car air conditioning units and oddly in some of the current fast change gearboxes. Where magnets pull the plate into contact with different discs to change from gear to gear.