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Water/Mud proofing alternators


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Seems every time I dip into a bit of muddy water my alternator dies (TD5 Disco if that's makes any odds).

Just wondering if anyone has overcome this problem as getting them overhauled at £50 a time is a bit of a pain!

I WD40'd it before hand this time, but still the charge light comes on :angry:

This never happened in the past, but I guess it might have something to do with:

a) bad luck

b) me removing the plastic under tray (well, it removed itself actually).

My starter motor took a hit this time also.

I don't fancy fitting another plastic undertray (makes repairs and maintenance a pita, and the old one is in bits/the bin).

Just after some ideas to save re-inventing the wheel :)

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I'm inclined to believe its "one-of-those-things"...

Jens old 300tdi disco had this problem, if it sniffed water the alt light would illuminate... anything from a faint, homely glow to a full-on blind-a-thon!

Our 300tdi camel 110 on the other hand, which uses the same alternator as the disco's gets a regular dunking and has yet to show any problems... and before anyone asks, yes, the bulb is still in the dash! :lol:

As Fridge says the brush packs are easily removable and fairly cheap to replace. Take yours to your local motor factor (Partco and the like keep a stock) and they should be able to find a match. Its certainly cheaper than buying a new alternator!

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You can't 'waterproof' an alternator, as the open design that lets the water in, is required for air flow for cooling.

As already mentioned, usually all that is required is a bit of a clean up of the brushes. On the older A127 style alternator you can remove, clean and replace the brush pack without removing the alternator.

On occassions, when the alternator has taken a proper dunking, I've actually poured clean water on to it, to wash the mud out. This works pretty well and has the alternator back up and running again, once it's dried out a bit.

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My 110 used to eat alternators, almost every time I played in the mud.

I started pressure-washing them before playing then WD40ing them, then as soon as I finished playing I cleaned the lights etc then sloshed the remainder of the water I carry over the alternator before driving home. Once back I re-pressure-washed it and reWD40'd it and I haven't had a problem since.

Will :)

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Why did they do that? What advantage is there for a road-going car?

Presumably in their top-end cars (140A+ alternators) there is so much stuff drawing power that the alt is working hard and insufficient airflow / space to keep it all cool. They (Bosch) were claiming space savings & reliability benefits from the setup too. Water is more efficient at moving heat around than air is, after all.

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A lot of buses have a ducted clean-air supply to the alternator, due to high engine bay temps I guess.

The 140A alternator on my BMW E34 breaker has this setup (the alternator is for sale if anyone is interested!  :P)

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Well I picked up my "refurbished" alternator from the local auto electrical specialist...not good :angry:

I got it home and, ignoring the bench vice marks and the chisel gouges where they's split it, and the fact that they hadn't cleaned one bit of it, and the seal was damaged when tyhey'd refitted it (yup, the old one!) I thought I'll fit it anyway and do the next one myself...

Bolted on the vac pump and the thing is seized solid. The drive bearing is sat cocked I think, that or the shaft is now bent :angry:

I've cleaned and refitted my other one and it works perfectly. What I thought were carbon brushes was actually grey coloured clay :lol:

So now I have a running vehicle, free to repair, and am able to take the shambles of a refurbished alternator back for a proper job or refund in the morning :angry:

Now I know why I do things myself <_< It took more time to f**k about with the "specialist" than it did for me to fix it myself :(

I have been looking and I don't reckon there's much of a way of sealing it against this sort of thing (or shielding it and ducting clean air to it). Don't think I could afford water cooled and there's really not much room to fit any extra bits of pipe etc.

Looks like I'll just get used to taking 'em off and cleaning 'em up :rolleyes:

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I did try that. The brushes have rubber seals over them, only loose fitting though. Loose enough to stop water and WD40 getting in, not tight enough to stop mud pushing past, and by the looks of it I mean pushing!

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You may be able to shield it from the worst if there is an obvious way that dirt is getting to it. BMW did fit sealed water-cooled alterators to some of their top end cars but I doubt you'd like the price or indeed the hassle of fitting.

last time i changed one on a merc the alternator itself @ Cost to the garage was about 650+v & was a special order from germany from the stealers

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I have used this company: http://www.woodauto.com/ to supply both new alternators and parts for alternators. On the whole, a complete new unit is usually cheaper than a supposedly 'recon' one!

Woods supply much of the trade with replacement and upgraded alternators - but will sell to anybody!

When I had a Lucas Alternator, I used to carry a new spare brush pack (about £10) and just swap them over when one became jammed. Then I could clean it out at my leisure.

I think you may find that many water cooled alternators brushes are just as exposed as an air cooled unit.

Si

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