Centre diff.lock actuator

uHu

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Two weeks ago when I started the car I heard a sound of a flickering relay. Sounded like behind the RHS kick panel. Tried to remember what was behind there, and started switching things off and on to see if something would stop the relay from flickering. Turned out it was the centre diff.lock relay, and when activating the lock-button, the relay was stable. But the diff lock light did not come on. Drove like this for a week, until I had some time on my hands. Measured a bit and found that the actuator motor was open, i.e. no connection between the two outer pins of the plug to the actuator itself. Since I had a spare one in the garage, I changed the actuator, and all seemed to be ok. Diff.lock worked and the relay was stable. Opened up the old motor and found a burnt rotor.
At the time of installing, I was trying to figure out how to be certain to put the actuator in in the right position. The handbook doesn't help much, it says: "Hint: At the time of reassembly, set the motor actuator in differential lock condition". I thought that couldn't be right as the diff was not locked, so I put it in in the unlocked position - same as the broken one was.
Now, after a week, the relay started flickering again !!!!! wtf. [email protected] My suspicion now is that the actuator can't quite move into it's fully unlocked position because it is mechanically stopped by the gear to the diff.lock, and that this was the problem all the way. As the contacts for the actuator motor are in the actuator itself, it has no idea about the status inside the transfer/differential unit. I'm thinking that this is was also the cause of the original motor to burn.

Is this theory sound - is this my problem? And: is there a foolproof way of positioning the actuator correctly upon installation?

I'm thinking of just moving the gear one tooth towards locked, or rather just move the contacts 2-3 mm past the end of the contact path for unlocking, and try again.

As it seems like most peeps on this forum have 80-series - I think the diff.locks are exactly the same.
 

warrenpfo

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On removing mine this is how I reinstalled it.

I plugged it in and then flicked the switch on the dash to extend the rod. With the actuator rod fully extended it was far easier to get the locking fork bolt hole lined up and the bolt installed.

I then with the help of an assistant aligned the actuator body to the 4 bolt holes and got my assistant to flick the actuator switch again to bring the actuator rod in and at the same time pull the actuator up against the diff housing.

Depending on where the locking fork is it may disengage if it was locked or it may not but so long as it brings the actuator body up against the diff housing you can then install the 4 bolts that hold it in place.

From there on its just a case of putting the cover plate back on and the other bits and bobs.

Hope that helps.
 

uHu

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This sounds like the rear diff lock. On the centre one there is no rod or fork visible when you just take the actuator out. There is only a gear-wheel visible, and the large-to-small gear wheel which is attached to the actuator.
On removing mine this is how I reinstalled it.

I plugged it in and then flicked the switch on the dash to extend the rod. With the actuator rod fully extended it was far easier to get the locking fork bolt hole lined up and the bolt installed.

I then with the help of an assistant aligned the actuator body to the 4 bolt holes and got my assistant to flick the actuator switch again to bring the actuator rod in and at the same time pull the actuator up against the diff housing.

Depending on where the locking fork is it may disengage if it was locked or it may not but so long as it brings the actuator body up against the diff housing you can then install the 4 bolts that hold it in place.

From there on its just a case of putting the cover plate back on and the other bits and bobs.

Hope that helps.
 

warrenpfo

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Sorry my bad I was too eager to help and did not read the post properly. Yes that is for the Rear.
 
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Jon Wildsmith

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I'm sure someone did an 80 series howto for this on ih8mud. Try having a look in the FAQ sticky in the 80 section of mud, I would look for you but food is waiting to be eaten :whistle:
 

frank rabbets

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uHu
How long have you had the car? If was installed incorrectly why would it suddenly play up?
I think your theory about moving things on by 1 tooth is all you can do. Presumably the wheel in the gearbox is not moving enough to fully disengage the contacts so needs to be retarded by one tooth.

I thought mine had locked on and removed it only for Jon W to come over to help and show me that I had pressed the diflock button. Didn't even know I had one as I had only just taken delivery and my 80 hadn't got a button. But it all went together OK.

Frank
 

uHu

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Finally got around to fixing my CDL, after getting a new actuator from Karl.

Took off the crossmember and jacked down the rear end of the box/engine assembly, took off the CDL actuator and connected the new one. I left the actuator outside the box, and tried working it with the cdl-switch. Yes, it worked OK. A few times. Then it didn't react anymore. Tried the switch several times, ign off/on, but no. Took the actuator down again to have a look at it, and at the plug. Funny, the motor was warm, a bit too warm for having run for a total of 5 secs. Tried changing the relay - same thing, no worky. Brought out the multimeter, found the problem - after some serious thinking. With both the relay and the actuator disconnected, there was still ground-connection on the pin/conductor for one of the endstop switches, telling the motor to run still. This ground is supposed to come only from the endstop switch, and with the actuator disconnected that's not possible. So the problem is in the loom somewhere. Started tracing, but as soon as I touched the cabling, the problem disappeared. I left the multimeter connected, set to "beep" (sound when connection), and tried all kinds of movement on all parts of the cabling, over and under the engine, and along the auto-box, but never managed to get it to short-circuit again. Until I find the problem, and nail it, I don't dare to connect the (still) good actuator. I suppose the easiest (fastest) is to put a new cable, outside the original loom, for only the actuator, or only that one signal. Not that elegant tho'.

Please fix it for me, by tomorrow morning please:mrgreen:
 

frank rabbets

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I wonder if the wiring fault is somewhere by or in the switch itself. This may have been moved around more than other parts of the loom over the life of the car so far.

Frank
 

uHu

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I wonder if the wiring fault is somewhere by or in the switch itself. This may have been moved around more than other parts of the loom over the life of the car so far.
Frank
The switch? This was measured with both ends of the cable disconnected. Well, disconnected from the relay at the upper end and the actuator at the bottom end, measuring at the pins of the plug for the relay, so no switches attached, only loom w plugs.

Couldn't find any suspicious-looking parts, plugs, cables, connections; but there must be somewhere I haven't checked. Could be in the J/B behind the RHS kick panel, next to the relay, or the plug next to the starter - although it looks good.
 

frank rabbets

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Faulty earth screw?? I can't see a wire being broken inside a loom.


Frank
 

frank rabbets

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The plug next to the starter might be worth taking out of its socket. It should be sealed but there could easily be corrosion inside. It's a bit of a ..........to unplug. I soaked mine in WD40 before I put it back in.

Frank
 
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