Starting Woes

Hi all, me again!
Long story short my starter has died, completely..
I've had it off and run direct to the battery with no avail, so i took it apart and with my fingers crossed gave it a good clean.
Tried it again and was simply rewarded with smoke...
So stripped it down again, the only evidence I can see of any fault is some signs or arcing/burning on the i assume bakerlite brush holder body..
Now a friend belives i can probably rebuild it, rather than try and find a replacement.
I've no issues actually doing it, but for those more electrically minded, what does it sound like has failed? Or given how vague that question is, how would one best go about testing?
Second question, if repairable, where would people go for parts?
Its a lucas 25668B or 2m100.
Ill add some photos next time I'm able to get out to it.
Thanks for any help.
Tony

Have you had a look here , a good section on starter testing , there is a parts book on that same website and google the part numbers

http://www.retroanaconda.com/landrover/2010/03/series-iii-workshop-manual/
http://www.retroanaconda.com/landrover/2010/03/series-iii-parts-book/

My series is on its third starter to my knowledge. In my ownership, it has never been a brilliant starter, it often seems as if there isn't enough juice to really make it spin. I've replaced the solenoid twice, the earth leads and the cables from the battery to the solenoid and from solenoid to starter, also I have had different heavy duty batteries, no difference. You can get replacement starters for less than £100 but they don't seem very good quality. I tried stripping my last defective starter with a view to servicing it but I gave up. When the current one finally gives up, Im going to get a high torque one, they are about £250. Starter contact brushes are available on eBay cheap and the bearings are freely available, apart from that it's just a case of giving everything a good clean, I used brake cleaner.

Col

The 200tdi one fits and started my series better than the original

I think it’s geared drive which helps, one on left has varied diameter casing is the 200tdi

steve2286w said:

The 200tdi one fits and started my series better than the original

Click to expand...

The trouble is my series is petrol. There is a high torque starter that will fit but they are nearly three times the price of a standard one. I don't know about the tdi's but the diesel series starter 3 mounting bolt holes and the petrol has two.

Col

steve2286w said:

I think it’s geared drive which helps, one on left has varied diameter casing is the 200tdiView attachment 231368

Click to expand...

Is the one on the left a two hole casing?

Col

Colthebrummie said:

Is the one on the left a two hole casing?

Col

Click to expand...

no both 3 hole mounting

Hi gents,

steve2286w said:

Have you had a look here , a good section on starter testing , there is a parts book on that same website and google the part numbers

Click to expand...

Was there meant to be a website in there?

I never really had much in the way of complaints with the starter when it was working, it did its job every time.

Unfortunately it's just given up now, here are some photos, can anyone see anything glaringly obvious?
I'm guessing with what little I know, smoke and absolutely no sign of movement would be a dead short to earth? (That's on the bench with a direct 12v supply).

Oops yes , it’s there now, I was thinking short when you mentioned the heat, you will need a multimeter , is the solenoid bit working and free
It looks quite dirty has it been rubbing

They take a lot of current, its hard to burn one out, not impossible but they are good for a few 100 amps for a split second. Have a close look at the brush holders and how they are fixed. I've had high resistance connections there and they get hot very fast.

steve2286w said:

Oops yes , it’s there now, I was thinking short when you mentioned the heat, you will need a multimeter , is the solenoid bit working and free
It looks quite dirty has it been rubbing

Click to expand...

Cheers, I'll have a ganders in a moment.
Yes the solenoid is a seperate component on this one, it clicks in and out quite definitively. Further to that bridging the terminals made no odds.

rob1miles said:

They take a lot of current, its hard to burn one out, not impossible but they are good for a few 100 amps for a split second. Have a close look at the brush holders and how they are fixed. I've had high resistance connections there and they get hot very fast.

Click to expand...

You'll have to forgive me here, but what actually happens to a motor when it 'burns out'?
Is it a degradation of the magnets, or melting the something? I simply don't know enough about them without a good amount of reading up..
I grew up in a very mechanical setting, not used to all this electrickery.
Cheers.

The attached document shows some info on testing starter motor.

Its a big DC motor. Its 4 pole which means its like tow motors together, it spins slower but produces more torque. That's why it has 4 brushes not 2. It has almost zero resistance so you will get what looks like a dead short when you test it. It also means the wires are thick. When you hit start and the solenoid kick in it takes a huge current (look at the CAA on the battery as a guide to what it could take). This is for a split second and as some as it starts to turn the magnetism in the motor causes inductance that makes it harder for the electricity to flow. This drops the current. As the motor spins fast it drops more. Never stop a starter from turning, they burn out in seconds.
The geared ones spin up faster because of less inertia and so their starting current drops faster. This makes them kinder on the cables(less copper needed) and brushes - smaller. But in the end if a starter produces 3hp it needs 3hp worth of electricity, gears or not.. You motor has electromagnets so its makes its magnetism, it will be slightly magnetic when you take it apart but its not important.
The big currents mean that any tiny resistance in a connection turns into a lot of heat and heat makes the connection worse. I have melted the ends of starters in cold weather but the wiring was undamaged (ie not burned out) so clean everything.
" of the 4 brushes are fixed to the case / earth. That fixing can be a bad connection. When my starter melted it was because of corrosion under the brush holders. I re riveted then after cleaning them up, filed it flat and it worked for several years until I got a new end cover. These old Lucas staters can strat much bigger engines than a 2.25 or 2.5. Mine Lucas M45 spins my 3.3 Perkins, that's 800 cc per cylinder at 18:1 compression with no trouble, but every connection must be spotless.