Broken wire through rubber on solenoid controller (on mini digger)

[microdig]

Hi

First post on here, so hello all. Have tried the search facility before posting but have not found an answer. If the question has been answered elsewhere, I'd be most grateful for a link.

I think that the offending article is called a solenoid controller. It is marked with the manufacturer's name TOKIMEC (Japanese) C12 5W followed by a serial number. It is part of an oleopneumatic system on a mini digger. There are two circuits, one of which is controlled by this object.

A switch in the cab area is used to select one of two functions by opening or closing a 12 volt circuit that enters the black box via a tightly sealed rubber top. The earth wire enters a few mm away.

The wire has become disconnected where it enters the rubber. Marked on photo with red arrow.

How is it possible to reconnect this wire? I have tried gently prising the rubber out, but it didn't seem too keen, so I didn't force it. The break is right on the surface, so no scope for soldering.

Any advice would be greatly appreciated. I have Googled for a diagram, preferably in cross section and to scale, but haven't found anything. Don't want to dig down into the rubber and make things worse.....

 

[poor mystic]

Hello Microdig
what a horrible problem! I bet the module costs plenty, too, so I understand why you'd want to fix rather than replace. Still I don't think there's a good prognosis without very clever surgery. I'm not sure that I'm capable of this repair.
I suppose I'd eventually try and make a clean job of it by cutting the rubber away so I could get at the break. I'd want 10mm (3"/16) of clean, uninsulated copper to work with if I were going to try and solder it, but I'd try with less if there was no choice. If you don't go deep enough with the cut to make a good job of the soldering, the repair won't last 5 minutes, so courage will be a factor.
I'd use a brand new scalpel for the cuts. Rubber is far easier to cut when it is stretched so if I had someone helpful with a pair of sharp-pointed tools to work with me so much the better. Such a job requires patience! Or possibly the rubber could be ground away at high speed using a dremel with a small spherical tool.
As for the soldering, I'd use a really high power, small-tipped, soldering iron.
I don't think there's a hope of resealing the original rubber, so I'd re-encapsulate the whole thing.Soldered wires fracture more easily than multistranded copper, so re-encapsulation is important.

When you describe this as a solenoid controller, do you mean that the solenoid is somewhere else or is the pictured module the solenoid itself? If it's somewhere else, it might be possible to make a controller to replace the faulty one, but it'd be hard to do well, quickly.

I'm not happy with what I've told you but I don't know how to improve on it. Hopefully someone else will chime in soon and there might be a better answer.

Good luck!

 

[duke37]

I posted here before but it seems to have dissapeared.
I agree with poor mystic that if you cannot get a new cable, the old one can be repaired. It looks as if the cable goes through a rubber plug which could be taken out without damage. If the wires are plugged in to the unit, new connectors should be fixed to the shortened wires (crimped?). If the wires are not long enough for this, the existing ends can be soldered on. The cable should be sealed in the rubber bung using hot melt glue and the cable should be restrained so that it does not flex.
Wish you luck.

 

[microdig]

Thanks for the advice so far. In order to attempt to clarify what the object in question is, I enclose a photo of it along with the part to which it is connected...

 

[poor mystic]

Good one microdig! I now believe in the repair a little more.
It looks to me like the broken part is actually the solenoid valve. That makes things a whole lot easier (if I'm right) since there's nothing very fragile involved.
Inside the unit, the multi-stranded flexible wires will be connected to enamelled wire, wound around the solenoid armature. If you can dig in and find that connection, it might be the best place to re-join your wire.
I think that an experienced automotive electrical technician should do the work. That way you'll get the best result at the lowest cost, especially if he's doing it as a Saturday cash job!

 

[microdig]

Fixed it! Dug down as far as I dared into the rubber (it wouldn't come out) until there was enough metal to solder a new wire, then covered the repair with hot glue.

Thanks to both of you for your advice.