How to remove the motor from a Lofrans Kobra?

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homer

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It looks as though there are just the 2 dome nuts on the top of the main casting. If I undo those, should the motor just pull off (corrosion adhesion aside)? And would the oil all run out or would the worm gear shaft still seal it? If anyone has the knowhow, it would be much appreciated.
 
Undo the two nuts.
The motor should but won't pull out due to corrosion.
Drill the studding out then you'll be able to remove the motor.
Now go to the chandlery to buy new studding to make up your own long bolts.
The oil will not run out.
If the motor is corroded you may not be able to renew the studding. In which case you should just live with the motor seized on.
In this instance drilling out the studding would result in you having to renew the motor.

Others may have successfully freed the studding but I never have.
Dismantling once a year would prevent it from seizing but how many people would do that?
On new studding smear with anti-corrosion compound.
If fitting a new unit worth smearing studding with anti corrosion compound before fitting to deck.
 
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I drilled a drainhole in the bottom of the brush cover before fitting the windlass, also made a canvas cover for it. I hope never to go through the removal exercise.
 
I had overlooked maintenance on the windlass and clutch mechanisms. It took much boiling water to free the Al drum from the shaft. All due to salt water corrosion. Shaft/drum is now coated with protecting grease. That job is now listed as annual.
 
Many thanks for the invaluable info. Actually, the motor came off quite easily and it seems to be ok. Attention now turns to the gearbox as somethiing is seriously amiss. Any advice on how to strip that apart would also be very welcome!!
 
If you've been in the habit of leaving the chain on the gypsy to snub the anchor, it's likely you have stuffed the thrust bearing on the worm drive.
Time for a complete strip-down I think.
 
Aah the delightful Kobra. Mine got slower and slower then eventually popped the breaker.

The body of the motor had rusted so much in 8 years not only had it rusted solid into its housing in the gearbox, but also into its hole through the deck. I had to chisel out the oak plinth then enlarge the deck cutout with a hacksaw to extract the blighter.

The rust between the motor and gearbox eventually succumbed to drilling out with extra long 3mm bits and soaking with plus gas over the course of a week.

After removing the brushes the rotor could barely be turned by finger pressure.
Liberal use of a blowtorch freed the studding in my case, but I noticed that just backing them off half a turn freed the rotor.
Somehow the rotor had got out of line as it had marks where it had rubbed against the coil cores.

After replacing the bearings and seal I cleaned out the oxidisation built up where the bearings sit in the Ali end caps and all was fine.

When I repaired the deck I installed a length of gutter vertically between the motor hole and the chain hole to prevent the motor being splashed from the chain.

All was fine for 3 years but it has now started binding again so time for another go at it. I fear that the extensive corrosion may have corrupted the interface between the motor body and the end caps, pushing everything on the skew again.

Sorry I cant help on the gearbox stripdown, though I did free the ratchet mech on the hand action drum by squirting WD in there and working to and fro.

Steve
 
As mentioned earlier I needed a new motor after two years.
The chain running close to the vertically mounted motor is a design fault, to my mind, and the plastic seal covering the brushes wasn't waterproof.
When removed, the brushes, and brush holders were corroded beyond economical repair.
Not wanting to be paying £400 for a new motor every two years I did a bit of a Heath Robinson.
I installed a hawse pipe upside down in the chain locker, to deflect the chain away from the body of the motor. It was cut so the angle was closer to 30 degrees than 90 so gravity could do its job.
Next I put sika-flex around the cover on the brushes of the new motor to effect a better seal.
The pièce de résistance was a large plastic flowerpot, with most of the bottom removed it was Sika-flexed and screwed upside down around the motor. A bit of overkill but I don't want to have to do it again.
 
Sounds like a similar attempt at preservation although rightly or wrongly I decided to leave the motor open to as much air circulation as possible. In hindsight suspending a poorly protected electric motor in the dank and salty chain locker might not of been a good move in the first place.

Out of interest, where did you get your replacement motor. If mine is finally toast it would be good to still utilise the holes in the deck, though I certainly wont fit and forget this time.

Steve
 
Belated thanks for the info on motor suppliers.
Stripped the motor this weekend. Once the end caps were removed the armature had to be driven out of the casing it was such a tight fit.
Either the armature has swollen or the pole shoes have somehow deformed. Judging by witness marks on one corner of one shoe I'm thinking the latter.

As a last roll of the dice I might try and skim the armature in a lathe or try and lightly grind the shoes to regain some clearance and see how that lasts.

Steve
 
Holy thread resurrection! I have a Lofrans Kobra that I have just replaced with a new Lofrans Korba. I'm going to get the old one back in action and then sell it to offset the cost of the new one. Having removed the motor I can see that I need to replace the brushes... but my motor seems to be fully of rotten oil. I think that's probably because the windlass gearbox seal has been leaking - am I correct? I don't think there should be oil in the motor (which there is).

Any tips? And does anyone have a good source of replacement brushes?

Many thanks.
 
Shuggy said:
Holy thread resurrection! I have a Lofrans Kobra that I have just replaced with a new Lofrans Korba. I'm going to get the old one back in action and then sell it to offset the cost of the new one. Having removed the motor I can see that I need to replace the brushes... but my motor seems to be fully of rotten oil. I think that's probably because the windlass gearbox seal has been leaking - am I correct? I don't think there should be oil in the motor (which there is).

Any tips? And does anyone have a good source of replacement brushes?

Many thanks.
Click to expand...

Strip the motor down and clean it with paraffin or in a garage workshop wash tank.

Cannot help with brushes except stip then out and measure the width and height to help find a replacement from a motor electrical repair shop.
 
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