Headlight range control on a W641

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Erik_Cartman
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My headlight range control isn't working. The control knob is the one behind the indicator lever shown in the link below.

It is some kind of a closed hydraulic system. Does anyone know of anyway to repair it stopping short of replacing the system (regulator, lines, actuator etc)?

Thanks.

 

https://www.google.com/imgres?imgurl=https://i.wheelsage.org/pictures/me...

consur
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Re: Headlight range control on a W641

Six posts below yours in Recent Posts there is an item on electric motor replacement of the hydraulic system.  Search the LWR Shop Essen.

Erik_Cartman
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Re: Headlight range control on a W641

Thanks. I'm hoping to repair rather than replace. I don't think I lost any hydraulic fluid. Don't understand what the problem is. 

Arnie
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Re: Headlight range control on a W641

The solution most likely to last is to convert to an electric adjustment system, as mentioned above.

The original control system is based on.a sealed hydraulic system and contains a water/antifreeze type of fluid.. The plastic parts usually crack somewhere losing the fluid.

If you find the location of the leak it may be possible to repair the crack with epoxy and to plumb-in a small header tank/container to refill the system with fluid. You will also need a small valve to close-off the tank when the system is full of fluid and the air has escaped. I think the plastic piping is the same type used in pneumatic systems and connectors and Ts are therefore cheap and readily available.

It has been reported that to install a new hydraulic system is extremely time-consuming and that it will fail again after a few years.

matthew.laight
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Re: Headlight range control on a W641

Just checked mine after reading this. Only the right hand headlamp adjusts. Presumably both headlamps are meant to adjust. Is that right?

Erik_Cartman
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Re: Headlight range control on a W641

Yes. Otherwise, it would be really weird. Kind of like cross-eyed :D

If it is such a widespread problem, I think a recall is in order.

Arnie
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Re: Headlight range control on a W641

Matt,

If one works, you may have another fault, like a dislocated adjuster mechanism. A leak would be fatal to both. You may have an easy fix. In this case.

 

matthew.laight
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Re: Headlight range control on a W641

Hi, unfortunately doesn't look like an easy fix. I took both headlight shrouds off and worked the adjuster knob. The driver side light plunger extends about half an inch when the adjuster knob is in the farthest range setting. The plunger on the passenger side light doesn't move at all. I will have to take the wheel arch cover off to investigate further, but it looks like fluid is leaking from the plunger.  Question: with the adjuster knob in the farthest setting would you expect the plunger to travel out more than half an inch? If so I suspect fluid had leaked. Photos attached with the adjuster in the farthest setting.

 

Arnie
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Re: Headlight range control on a W641

Usually the actuator (the plunger connected to the lights) will leak somewhere where the fluid plastic pipe connects., through a hairline crack in the plastic.

I think there may be a market for a retrofit kit here, made of metal parts, with a refillable fluid.