Battery Not Charging

[NEG]

Guys looking for advice/guidance,

The battery on my 1.3 Sprint isn't charging, dash light is staying on and voltage when running is 12v with not variation.

Alternator is Bosch, there seems little to service, I've pulled the brushes and they are below the the 9mm mentioned in the Haynes manual.

Is it worth a punt in changing them or should I look for a new unit?

[Sud 145]

Can you take them out and reverse them - just a thought. Or while it's apart fit new ones, they can't be much surely.

[junior]

I had same problem. Took it to a local car electrics place. Chap tested it, found it okay and said

`look I will just clean this and that and it will be fine for years'.

Did not charge me, so I gave them a tenner for their Xmas do and put it back on to find it worked.

Hope your equally lucky.

[Sud 145]

£10 well spent.

[NEG]

I've cleaned the brushes up but no dice so I've ordered what I hope is the right replacement part....will see if it fixes it.

[NEG]

Swapped the regulator and still no luck, looks like it’s the diode pack or one of the windings. It is producing a voltage around 6v @ 2000 rpm so there’s hope!

[NEG]

Having been quoted £175 for an exchange unit Decided to have a go myself.

Hopefully, this may help somebody else, although at the moment I'm waiting for parts.

Couldn't get the pully off so undid the 4 long bolts and took the rear part off first. These are slotted set screws so use a correctly sized screwdriver, you don't want to bugger these up. They gave an initial 'crack' then seemed to require more forces to let go. Use a vice to hold the alternator. Thankfully all went ok.



I then used a small nylon headed mallet to knock the unit apart.



Some wear on the slip rings, the bearings need replacing.



Stator and Diode pack, soldered coils.



The rotor continuity tested ok and the three coils on the stator where all ok, except that they tested for continuity to the alternator case. Hmmm, I'm not sure that is correct...

So, I decided to remove the diode pack, this one is soldered, don't try to unsolder until you have knocked the stator coils out with a small drift and hammer from the rear opening in the case.



Use a good 25w iron to unsolder and make sure the wire ends are straight before you struggle to pull the red hot wires with burning fingers!

I cleaned the diode pack up a bit and it looks like this:





This is from JCR Supplies so I've ordered one £23.... http://www.jcrsupplies.co.uk

Just need to find the bearings now.

Oh, managed to undo the Pully nut by holding the rotor in a vice with just enough grip to keep it still...



Washer Sequence:

[alfadave]

Have a look at ebay item
281856141840

recon alternator £58 delivered 12month warranty

Seems to be for an S1 Alfa 33 , so should fit your sprint ok?

Dave

[NEG]

Thanks for the link, it looks the same, I’ll keep it in mind if mine doesnt work out

[Spacenut]

Yes, keep going NEG, you're nearly there now! If two of the phases are shorted to ground that would explain a reading of 6v - only one of the 3 phases is still working. I can well believe the unregulated (full-field) output would be 18v or so. Replace diode pack, re-assemble and hopefully away you go!

I've got an old alternator with failed bearings that could do with a rebuild, so I am keen to see how you get on. Good luck!

Lauren

[KevJTD]

I've never taken an alternator apart so am keen to see how you get on, electrics easily confuse me!

I haven't bought a new one in ages though, far too expensive. A local auto electrical place does them up usually with a quick turnaround, usually around £50 done too.

Really keen to see how you get on though.

What causes the alternator to drain the battery? The 145 drains it within a couple of weeks, previous owner told me an auto electrician diagnosed the alternator at fault...be handy to try and fix it myself..

[kammatic]

Fair play to you for taking that to bits mate

[Simonsud]

Diode pack will cause drain diodes are basically a one way valve for electricity
. The alternator on my sud is the front part of the original Bosch one with the rear and insides from a vw do it’s now 60 or 70 amps can’t remember exactly or what model it came from but it’s a lot better than 45amp original

[NEG]

Many thanks for the words of encouragement!

PartII

Found the bearings on-line here: https://www.qualitybearingsonline.com

Pretty impressive service, ordered yesterday after the diode pack and they where on my hall mat by 8:30 this morning!

The bearings I needed for this alternator where SKF 6203-2Z and SKF 6201-2Z

First job was to pull off the front cover, use a 6" three leg puller, 4" is too small



Once that is off you need to undo these two set screws to get at the bearing, they are tight and as before use a vice and a flat blade screwdriver of the correct size



Dried up grease...strange thing is this bearing was only sealed on one side, the replacement is sealed on both.




Use the puller to get the other bearing off the rotor as far as possible and if necessary use a drift and hammer to finish it off. The shaft on my puller was larger than the rotor shaft so it only came part of the way off. If you also have a 4" puller that may work better.

Old and new:



At this point I cleaned a few bits up with Paraffin and found the Bosch part number under all the crud:



Next, put the new bearings in. For the smaller bearing use a 12mm socket on the inner race to tap it down the shaft until it seats fully.





The front bearing simply pushes in, don't forget the cover plate.



With luck the diode pack will turn up tomorrow.

[NEG]

Diode pack will cause drain diodes are basically a one way valve for electricity
. The alternator on my sud is the front part of the original Bosch one with the rear and insides from a vw do it’s now 60 or 70 amps can’t remember exactly or what model it came from but it’s a lot better than 45amp original

The diodes shouldn't allow any current to flow in the reverse direction unless their reverse bias (voltage) limit is exceeded and generally, if that's the case, they are destroyed. They usually fail open circuit. There may be a current leak back through the voltage regulator or the suppression capacitor ...

Kev, maybe measure the current draw with a multimeter when everything is switched off, things like alarms, clocks, boot lights etc. can drain a battery...you could also see if there is a resistance between the B+ terminal on the Alternator and the case/negative, ideally is should be an open circuit.

[KevJTD]

Impressive stuff there, always satisfying to repair yourself. Electrics though baffle me..
So if I check between the B+ and casing there shouldn't be any reading? If there is then this could be the cause of my voltage drain?
I've checked the usual culprits like boot light, radio etc. It does have an aftermarket alarm which I don't use, maybe that could be the cause? Must find it and unplug it..
Would rather be the more scientific method of checking though...
An idiots guide for me to use on checking would be greatly appreciated sorry for the thread hijack by the way!

[amichie]

This is worth a read.
https://alternatorparts.com/understandi ... ators.html

[NEG]

Part III, final reassembly…

The diode pack has arrived, well, it arrived yesterday but I didn’t know, postie had left it in the garaged my dear missus forgot to tell me!

Old and New…



First step is to screw it into the rear housing



Then offer up the stator, making sure the three phase wires match up to the diode hoops and are fed through and bent into place.



Use a 25w soldering iron and solder them up

Time now to fit the front cover and bearing to the rotor, it should just push on.



Place the washer raised ridge down facing the bearing, this is an interference fit and will require tapping down with a deep socket, an old spark plug socket will do.







Here I ran into the first of two problems. The rotor was stiff to turn, not terribly so but it was stiff and it should turn freely. What I found was there is enough moment in the plate that holds the bearing in for it to not be central and so rub against the rotor shaft…..this plate:



So I had to pull the blasted thing off again re-centre the plate and reassemble! This time is span freely.

My next issue, like a muppet, I’d forgotten how the washers went back on despite my photo from earlier! If they don’t go back in order the pulley dishes won’t mate with the key and the nut won’t go on fully. 2 hours later of mucking about, tea breaks, head scratching I remember there is an exploded diagram in the Haynes manual! Doh! “Assembly is the reverse of the disassembly” yeah but not if you are a muppet!

The fan blades go on first followed by the large washer the right way around like this…



Then the thicker washer



Pully halves/dishes





Then the last washer, split washer and nut.



Now reassemble the back and front parts and screw back together, note the orientation of the cutout to the mounting lug…



The last thing is to put the regulator back in…it pushes against a spring contact on the diode pack, it needs a bit of force to go back in, hold it in place and get the screws in. I’ve reused my old one, the new one I’ll keep as a spare.



I bolted it back into the car and connected it all up, started the car and the bloody warning light stayed on! Gave it a few blips on the throttle, light still on, %$^%^%&^$£&^

Got out of the car, attached my volt meter to the battery and blipped the throttle again, the voltage jumped up! Yes, it works, not sure why it took a bit of time to get going, I may have not had the regulator brushes seated correctly on the slip rings. I get 12.5v on idle and 14v now at 2000rpm and the light is now out!

Result. Im one very happy (and relieved) bunny.

Costs:
Un-needed regulator £12
Diode pack £23
New bearings £8
6” Puller £16

Total £59

[junior]

Good effort , rather impressed at your determination.

[Spacenut]

Well done NEG, a good result and a well written and illustrated guide for the rest of us to follow!

[KevJTD]

Fantastic effort, well impressed

[Sprint88qv]

Well done indeed. There’s something very pleasing about using old school knowledge and skills to beat the odds

[Kegsti66]

Excellent result and write up.
Nice one, very useful.