Cheap tools heads up

There is a weight restriction that means that anything bigger than 750kg needs brakes (gets coplex with car brakes), so most people use a little fiat or a smart car or whatever, the dolly is generally a simple Aframe that goes directly on the front of the towed car (rather than mess about underneath) Large motorhomes don't notice the small amount of extra load and it is easy to forget it is there.

Does that mean that when I towed a mate's cambelt-victim Vectra back from Wales on a hired car trailer using my 2.3TD Carlton, I was breaking the law, or would the trailer almost certainly have been braked?

AstraVanMann pretended :

Any but the smallest and lightest of trailers are fitted with over-run brakes.

like Harry said, any large trailer inc. car trailers where the total weight is over 750kg legally needs brakes, usual type is overrun and if they work well you will hardly know they are there.

I see what you mean about complex over the 750Kg limit. This links the overrun to the brake pedal of the towed car.

I can't see how a cable pulling a pedal without servo assist would be very effective. I'd also be a little worried how the lights are wired though, especially with some modern cars where the lights are connected directly to the ECU.

The other problem is when you go over to Johnny Foreigner land, the rules there are all different again (no EU harmonisation)

It depends how much the trailer weighed & how much else was in them (IIRC a Carltons rated to tow 1600KG & a Vectra weighs about 1400KG so pretty borderline). If it wasn't braked then it's illegal as it would definitely be over 1/2 the weight of the towing vehicle & over the 750KG maximum.

I have been so lucky over the years, the brakes have never worked on my car trailer and I tow it with a sierra, yet (touches wood) I have never been stopped even with a couple of tonnes on.

"Mrcheerful" gurgled happily, sounding much like they were saying:

Small problem. It's 750kg max laden not 750kg kerb weight - which means that it's only stuff like Aixams which can legally be A-framed unbraked.

Assuming you mean a car with multiplexed electrics, you either use the car manufacturer's method, which is fairly expensive but works very well, or a third-party solution that involves a box of relays.

Either way, it's a non-issue.

Chris

Even adding a (mechanical) relay to my BMW upset the bulb failure warning.

A typical car relay coil will pull 1.5W. The tolerance on a 21W lamp is greater than that.

Does your BMW have the infamous under-rated rear light cluster connector...?

Chris

It 'polls' the system even with the lights not on. And 1.5W is quite a percentage of a 5 watt tail light bulb. Get roundable by using a transistor to do the switching so as to not load the circuit.

It's a bit like a Molex between harness and PCB - and haven't had any problems with it. Yet.

I'm surprised that it is considered necessary to monitor *over* current to that degree, if it was monitored at all. Surely the point is to check for bulb failure, which would only need under current checking?

The ones I'm thinking of are the connector to the rear light cluster; probably a good bit earlier than your car. Any decent electrical or electronic tech would have thought them rated at perhaps 500mA. The earth pin carries tail light, indicator and brake light current. For a while...!

Chris

Pretty certain mine does. It's just an inline PCB connecter similar to a PC IDE connector etc. But would be easily sorted if it failed by hard wiring to the PCB and adding a more suitable in line connector.

Its a wonder you've been able to stop!

It is called driving skill, looking ahead and planning, instilled from an early age driving real old rubbish with lousy brakes, poor steering, sometimes no clutch etc. etc. If you drive well then light braking is all that is needed and the 4x4 has very good brakes in any case, now when I used to tow with the HA Viva it was a different story, that was so light and the brakes so poor that I had to double up the spidey sense since it would not have been able to stop in a hurry, likewise the Escort van with drums on the front, that used to get exciting on the way to Llydden race track.

A non-issue if carried out correctly. Like I've found with tow-bar fitters, some don't stick to simple rules.

I think this has a lot to do with the appearance. When I bought a dodgy car transporter a few years back, the first thing I did was fit new wheel-arches and reflectors making it look relatively tidy. It only ever had brakes on one axle, and no suspension at all, but never attracted enough attention for anyone to notice. That said, I'm a _lot_ happier now that I've replaced it with a decent trailer.