Thread: D2a TD5 - low voltage when driving - sick battery or alternator?

I had similar problem with battery light intermittently coming on and Nanocom reading below 11v. I bout the kit from Uk, new bushes and regulator for about $70, pig of a job and involved making my own spanner, but did the job and that was about 4 months back. Much cheaper than a replacement alternator and reckon worth the effort trying this before buying replacement. Annoying part was that the constant charging and emptying of the battery knackered it shortly after and have had to buy new battery. But good outcome all the same.

Originally Posted by surfingooner

I had similar problem with battery light intermittently coming on and Nanocom reading below 11v. I bout the kit from Uk, new bushes and regulator for about $70, pig of a job and involved making my own spanner, but did the job and that was about 4 months back. Much cheaper than a replacement alternator and reckon worth the effort trying this before buying replacement. Annoying part was that the constant charging and emptying of the battery knackered it shortly after and have had to buy new battery. But good outcome all the same.

I found that removing and fitting the alternator to be one of the less tiresome jobs that I have done on my D2a Removing the old brushes and soldering the new ones in is bloody fiddley though and requires a bit of patience.
I didn't replace the regulator on mine as when I took the brush pack off they were worn right down and were barely making contact with the armature so it was quite obvious that they were the cause of the problem.
I paid $19.90 for the brushes from a local auto sparky But they can be had on eBay for about $8 So this job was also the cheapest repair I have ever done on the Disco and I also recommend giving this a go before spending hundreds of dollars on a replacement alternator

Originally Posted by knp

I’ve replaced the alternator on our 2003 td5 D2 and it is a real pain. Very tight squeeze in and out past the radiator. Undoing the fan was interesting too.

The original alternator failed due to oil ingress onto the commutator and brushes. I made a post some years back about that and solar powering a D2 to get home.

The source of the oil was then and still now remains a mystery.

The good folk at MR Auto are an excellent choice if you’re in Brisbane.

I'll solve the oil mystery for you , the seal on the front of the alternator wears and lets oil in from the vacuum pump.

Pulled the alternator out yesterday. Took the battery, ECU and tray out to get easier access.

Seperated the vacuum pump and alternator assemblies. No sign of failed oil seal or oil entering the alternator end.

Pulled the back off and found the slip rings unevenly worn and the brushes on the brush box matchingly uneven. Perhaps the cause of the intermittent charging and lack of volts?

Had an alternator on the bench from a mates UZJ100R that I replaced a while ago. Also a Denso OEM unit. Pulled the back off that and found it had the exact same brush box, rectifier and regulator fitted to it. Pity it was also faulty in somewhere so no point in swapping it over.

Have been debating rebuilding mine, but with out being able to determine the exact faulty part, no replacement slip rings there’s little point. By the time I purchased a new regulator, rectified, brush box, removed and replaced bearings it would be a fair bit of the price of a brand new replacement unit and still be old inside (e.g. some of the insulation etc) and the vacuum pump.

Here is a link to the slip rings for a TD5 alternator..
$15 a year ago.
Slip Ring Nippondenso 8.8 X 14.5mm

Cheers