Spare alternator?

[cnskate]

Do you guys often carry a spare alternator? I have the well regarded but heavy ND in my Jeep XJ with a 120K miles. They often go 200k, but not always. I have a Deka battery and a jumpstarter too.

 

[The BN Guy]

I just installed a new one about a year ago. I keep the spare in the garage and typically don't take it out with me. Now tie rod adjusters, yes. That's a week part on my rig. The alternator is mounted super low on my Frontier. Since I don't go real crazy when wheeling I don't carry it since I can usually make it back to cibilization before my rig dies.

 

[IggyB]

I replaced mine 2 years ago and carry a spare. It helps to have 2 mechanically identical vehicles in the family - Frontier and Xterra. Spares are easy to justify.

I carry a starter too.

 

[BiG BoB]

I wouldn't worry about it if you're in a manual diesel vehicle with no computer

Anything else.... I'd be hesitant to go bush without a spare of everything!

 

[The BN Guy]

That's why I wheel with my 'San brothers and sisters!

 

[BiG BoB]

That's why I wheel with my 'San brothers and sisters!

Ahhh, but then you don't get the serenity, the joy of being on you're own with just you're faithful cruiser (and maybe a female companion to keep warm with)

 

[Grim Reaper]

ND alternators used on Toyota, Nissan and many others are pretty tough. Short of burning up the bearings for water contamination the only thing that really seems to go bad is the Brushes. You can order them for about $10. from many auto parts stores like Advance or Autozone or Partsamerica.

 

[AndrewP]

Sometimes the alternater is a critical pulley in the system. If that's the case, it's reasonable to carry a spare. If you go to the effort of buying a new rebuild, It makes the most sense to swap it in and carry the old one as a spare. I had a spare smog pump for my FJ40 for the same reason before the desmog.

 

[KMR]

Most alternators are actually quite simple to rebuild in the field. Bearings do not tend to go without warning, so if you do not ignore an issue with them they probably will not leave you stranded. The only parts that do tend to fail in the field are the brushes (as mentioned) and the voltage regulator, both are very small and light replacement parts, the VRs don't usually require anything more than a screw driver to replace, and the brushes are not much harder.
Get familiar with the alternator that you have, disassemble it and take note of what tools it requires, see if you can do it in the field and then make the decision to carry a spare.
Spare alternators are pretty heavy for a bunch of copper wire that wont actually need to be replaced.
Kevin R.

 

[cnskate]

Good point. Maybe I'll just take my used spare apart and bring the VR and the brushes.

 

[madizell]

Rather than carry an entire spare, if you are going on an extended trip, pull the alternator at home and verify, clean, and lubricate as needed so that you start with a good unit. You should at that point be good for another 5 years. If traveling in extremely dusty places, or if you submerge the unit repeatedly, particularly in muddy water, you may need to take it apart and clean it in the field. Brushes are an obvious wear item but are easy to replace. Bushings or bearing are the next wear items but if clean and well lubed before you start, they are very unlikely to fail in the field. If you submerge in dirty water, clean the alternator when you can with water (unit turned off) to remove accumulated dust and debris. I have never had one fail in the field.

However, I have had an idler pulley fail in the field, and if you have a serpentine system, it is perhaps the one thing that no one ever looks at or thinks about. Some are constructed so that they can not be serviced, in which case carry a spare. If serviceable, carry a replacement bearing as these are generally available at a bearing supply or NAPA for only a few dollars. If the idler fails, all accessories fail with it including the water pump. I would consider the idler more important than the alternator in this regard.

 

[cnskate]

Thanks for the tips. I considered the idler pulley too. It's a common problem on my Saab, so I thought one for the Jeep might be a good idea too.

 

[rusty_tlc]

Sometimes the alternater is a critical pulley in the system. If that's the case, it's reasonable to carry a spare. If you go to the effort of buying a new rebuild, It makes the most sense to swap it in and carry the old one as a spare. I had a spare smog pump for my FJ40 for the same reason before the desmog.

FYI it takes a couple of minutes to gut a FJ40 Smog pump and still leaves it functional as an idler pulley. I ran mine like that for a couple of years before the PS conversion.

cnskate: If you start carrying spares of everything that might fail you will soon have no room left for gear. Instead just carry what is likely to fail on your rig. For example Toyota's have a reputation for breaking birfields, it makes sense to carry a spare birf if you drive a Toyota. Jeep seem to break rear axles a lot.
As was posted earlier an alternator seldom fails with no notice, unless I drove a rig that had a reputation for unexpectedly losing alts I would leave the spare at home.

All that aside, if you want to carry a spare why not set it up as an onboard welder? For most of us getting double duty out of everything we can is always a plus. If you do a web search there are a ton of articles on building an OB welder system using an alternator.