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120A Alternator Refurbish

naki_k
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Posts: 27709
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

120A Alternator Refurbish

Postby naki_k » Sun Oct 15, 2017 10:55 pm

Has anyone ever refurbished a 120A Alternator?
I was going to try once before, but could not undo the pulley nut. Now I have an impact gun, it comes off in a second! So a much better chance to have a go.
I watched a few You tube videos to get some kind of idea, but I suspect there will be a specific weakness of these Denso units. Any idea what parts fail?
I am hoping that most of the parts are available new. I know some parts are on JCP even.

Has anyone on here done one?

These units have quite s high failure rate now I think. Especially after a time of no use.
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 3.2 XJ6 SportPack Manual
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300

katar83
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Posts: 2458
Joined: Tue Aug 23, 2011 11:17 am
Location: Cambridge

Re: 120A Alternator Refurbish

Postby katar83 » Mon Oct 16, 2017 10:27 am

Nice to have an impact gun on hand, dont you think? Makes some of the jobs so much easier :)
No idea what's failing on these specifically but generally its usually:
1. brushes
2. rotor rings
3. voltage regulator
4. bearing
5. some other mechanical parts

Back in Poland, most of the alternators get refurbished, the cost is almost always between £20 and £30 and in some cases where more parts are needed its probably up to ~£50-£60 max for a fully refurbished unit. I swapped two alternators on my Jaguars, if I had the tools(like I do now) and parts at the time I would definitely try to fix it first.
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.

naki_k
Super Moderator
Posts: 27709
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

Re: 120A Alternator Refurbish

Postby naki_k » Mon Oct 16, 2017 10:59 am

I think it’s becoming more of a necessity with these 120A units with a high failure rate.

As always, the right tools simply make things possible.

Everything is repairable, it’s just down to money, tome and convenience really.

I just had a quick look on JCP.
The parts most likely to be needed are NLA or silly expensive. So I will likely find the part numbers off the parts and net search.

https://www.jaguarclassicparts.com/uk/j ... r-assembly

Incidentally, this unit I have spins as normal, so I know the bearings are good.

I had one refurbished a number of years ago, and multiple parts were replaced. Maybe they just swapped everything? Rather than diagnosing which component actually failed? The rectifier and regulator were changed for sure, as they are visible through the rear vent, and were clearly new. When I find the part numbers, I can price them up anyhow.
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 3.2 XJ6 SportPack Manual
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300

katar83
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Posts: 2458
Joined: Tue Aug 23, 2011 11:17 am
Location: Cambridge

Re: 120A Alternator Refurbish

Postby katar83 » Mon Oct 16, 2017 11:18 am

Silly prices indeed! I'd go with brushes check first, they can be bought on ebay for just a couple of £ and regulators seem to cost ~£20 too so not too bad.
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.

katar83
Distinguished Mbr
Posts: 2458
Joined: Tue Aug 23, 2011 11:17 am
Location: Cambridge

Re: 120A Alternator Refurbish

Postby katar83 » Mon Oct 16, 2017 11:34 am

Just had a quick look and the voltage regulator can be bought for £20 on eBay, 126000-1200

Full parts list and some numbers(that can be used to find them in UK) can be found here:

http://www.ebay.com/itm/ALTERNATOR-REGU ... 1528718571
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.

naki_k
Super Moderator
Posts: 27709
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

Re: 120A Alternator Refurbish

Postby naki_k » Mon Oct 16, 2017 2:23 pm

katar83 wrote:Just had a quick look and the voltage regulator can be bought for £20 on eBay, 126000-1200

Full parts list and some numbers(that can be used to find them in UK) can be found here:

http://www.ebay.com/itm/ALTERNATOR-REGU ... 1528718571


That would be nice and easy if it was just that, as that can be changed from the back without even opening the main unit.
Thanks for the link.
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 3.2 XJ6 SportPack Manual
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300

naki_k
Super Moderator
Posts: 27709
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

Re: 120A Alternator Refurbish

Postby naki_k » Mon Oct 16, 2017 2:31 pm

And the rectifier. Well I haven’t checked the part numbers but it’s looks exactly the same if the pics are real.

http://www.ebay.co.uk/itm/Jaguar-XJ-XJ8 ... ect=mobile

Plus a uk based supplier for the regulator

http://www.ebay.co.uk/itm/Jaguar-XJ6-xj ... 0005.m1851

And the Brush. All three parts from the same seller.
https://m.ebay.co.uk/itm/Jaguar-XJ-XJ8- ... mwBanner=1
Last edited by naki_k on Tue Oct 17, 2017 10:39 am, edited 1 time in total.
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 3.2 XJ6 SportPack Manual
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300

katar83
Distinguished Mbr
Posts: 2458
Joined: Tue Aug 23, 2011 11:17 am
Location: Cambridge

Re: 120A Alternator Refurbish

Postby katar83 » Mon Oct 16, 2017 3:15 pm

Yes and I suspect 90% of the faults will be voltage regulator/brushes related so well worth checking.
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.

naki_k
Super Moderator
Posts: 27709
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

Re: 120A Alternator Refurbish

Postby naki_k » Mon Oct 16, 2017 4:14 pm

Ok, I may just get those ordered then
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 3.2 XJ6 SportPack Manual
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300

naki_k
Super Moderator
Posts: 27709
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

Re: 120A Alternator Refurbish

Postby naki_k » Tue Oct 17, 2017 10:44 am

Those three parts are now ordered. £55 total.
Ok so the cost is not far off that of another used alternator, but if the weak points are replaced with brand new parts, it’s a better guarantee that it should last a long time?
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 3.2 XJ6 SportPack Manual
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300


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