Rear locker motor rebuild - 'scuse my ignorance but ..

[Chris]

The rear locker packed up in Russia. No biggie. I managed. But electrically it all felt and sounded right, just no activity at the motor. I was right - when I pulled it tonight, the magnets had all come unglued. Now they are in order but all stuck together in a clump. Am I right in thinking that they go 12, 3, 6 and 9 in the top hat? It's just that the witness marks inside look like they are unevenly spaced. Well that can't be right can it?

C

 

[Trevor]

From memory it is the quarters of the clock face as you describe. Witness marks from previous owner attempt or magnets moved position before last glue attempt had dried fully?

 

[uHu]

Pics of the magnets:
https://forum.ih8mud.com/threads/nijas98hundie-build-thread.1060066/#post-11677665

One more:
https://forum.ih8mud.com/threads/du...d-cruiser-sas100.773545/page-10#post-10311906

 

[Chris]

That's the dog's. All I need. Been a very long time since I did one and this is original never before touched inside. But the glue has just given way after 23 years.

Case closed.

Ta

 

[frank rabbets]

You might have to reopen the case if you don't know the polarity position of the magnets.

P>S> I used araldite on mine.

 

[Chris]

Magnets all in place Frank. I opened it very carefully from experience and they were all stuck to the rotor. All marked and in order ready to go in.

 

[frank rabbets]

A wise move to mark them Chris. Something I fell down on.

 

[Chris]

Well it's not helped me Frank. Locelr was working perfectly in Russia then it stopped. THen one day miraculously it came back for a while then stopped and that was that. It came off the axle in one. All the bolts undid easily and the casing is in excellent condition. The plugs are clean and well sealed. I have replaced the magnets and since checked that they hadn't come off again but it doesn't work. The magnets are in the correct order, that I can assure you. I marked them 1,2,3 and 4 as well as N & S before they ever came out of the top hat. With the residual glue on them, they could only go in one way. So that's a banker. When I spin the motor by hand, the actuator rod moves effortlessly from limit to limit. The brushes are clean and sliding in their tracks. I have tried the power probe in there and get a circuit but no motor activity at all.
It might be that the internal limit switches are jammed so I will heat the bolts slightly and get the gear casing open for a look. Aside from that it might be one of the small electrical components in there. Now, sure it could be the cabling and lock computer, but that was working perfectly and the magnets had come off so I am betting the ECU which is firing the centre and front lockers perfectly is working just fine. I can hear it click when I turn the dial. Easiest way is to connect a working motor. Which obviously I don't have!

 

[Chris]

OK so the case is open and it all looks quite decent in there. However the motor spindle feels a little tight. It might be that it took a know when the magnets came off so I shall check it for true. It's only a 12v motor hardly a 1HP monster so if it's jammed then it might just not want to spin from the get go.

 

[StarCruiser]

Could it be that the glue has set with a magnet slightly touching the armature? There isn’t much gap usually and sometimes glue can bulk up a bit. I believe @Ben had a similar problem when he rebuilt his.
It may pay you to isolate the motor contacts and test it with a direct 12v supply on the bench if it’s possible and you haven’t already.

 

[Chris]

Don't think so Rich. It was superglue so no bulking. There's quite a bit of clearance in fact. I've been trying with 12v supply all day and nothing. Not even a strained buzz. Nothing on the actual loom either when I plug it in.

Grrrr

 

[StarCruiser]

You could try putting a 12v bulb in series with the motor and rotating it. This will limit the current while showing if you’ve got a circuit through the armature and brushes that is passing a current. Fairly limited use but might show up a problem. The true test is to check on Ohms between adjacent commutator segments and get roughly the same reading. If the reading varies and goes highish between two by comparison then there is a break. It may be the motor stopped, dropped the magnets, then sat with Power connected long enough for the winding to burn out.

 

[Chris]

Sorry, what?

Ha ha

 

[frank rabbets]

From memory there is an adjuster to set some end play in the arm' spindle. I would flick the contacts with a live wire to see if there is a spark which proves some level of circuit pathway.

You'll find it.

Could be the Russians have jammed it.

 

[Chris]

There is Frank. I have removed and cleaned that out. Yes it adjusts the end float in the spindle. But wait, there's progress. I was pondering what Rich had said (given that he often does make some sense ) and whilst I knew the magnets were in correctly, I did wonder if the rotor might be touching. Looking at the wiring diagram I saw that putting current across the two green wires should spin the motor. Nothing. I loosened the top hat and started to rotate it. Bzzz. Bit more Bzzzzzt, bit more Whizzzz. It lives! I am guessing that the top hat probably met with a blunt force trauma (no idea where that might have happened ) so it's not round any more. I do have an old motor up at the unit so I shall rob that for spares today and see if I can't Frankenbuild one.

 

[frank rabbets]

I thought for a minute it was stuck in limp mode.

Parts are interchangeable...... one of the beauties of mass production.

 

[StarCruiser]

I thought for a minute it was stuck in limp mode.

Is that where one wheel goes faster than the other…?

 

[Chris]

Done, sorted, fitted, working. Diff locks and unlocks. Robbed a top hat from a duff centre diff lock. In perfect fettle, spun up straight away. Bit fiddly getting all the internals lined up again though.

 

[clivehorridge]

Done, sorted, fitted, working. Diff locks and unlocks. Robbed a top hat from a duff centre diff lock. In perfect fettle, spun up straight away. Bit fiddly getting all the internals lined up again though.

Great that it’s sorted Chris, is the old top hat visibly distorted?

It’s good to note these findings. I’ve a new actuator on the rear diff, but nothing’s new forever...

Just found I’ve got an almost invisible puncture in the can on one of my OME rear shockers, peeing oil or whatever is that’s inside them, that cost me 2 new replacement rear shocks...

 

[Chris]

Hard to say. What I think it is, is the alloy mating face had 'blown' as it so often does and had distorted the rim of the hat. When I cleaned it all up and refitted the can, I pulled it down to what was effectively a new face. I reckon that was enough to twist it somehow. The spare one I had actually came away clean with the original rubber O ring, so I bedded it down on that and the resat as they say is broccoli.