Greetings,
Had this problem with one of our fleet, starting after install of a new battery, tried the felt rings, grease, etc., etc.,......., for a couple of years. Finally cleaned around post well and sealed with black RTV.
The seal around post was broken and acid was constantly wicking up around it, a year later it is still uncorroded.
My 2 cents.

Hope this helps, rcs

probably just a bad battery, had the same thing happen, clean it & a month later there would be a big snowball on top of the post, battery finally gave up the ghost and have had no problem with the new one.

I'm surprised to hear so many Coke recommendations.

I would use baking soda if the battery was removed and you were worried about acid that had leaked down around your battery tray, but I wouldn't dump either one of these products on your battery while it is installed. This is a receipe for a rusted out battery area.

Personally, if I am in a hurry, I spray both terminals with WD-40 or PB Blaster or a similar product to prevent corrosion. Otherwise, I use a Q-TIP and spread wheel bearing grease on the terminals and connectors.

I haven't had to clean terminals in the last 20 or so years due to corrosion build up on any of the cars I maintain, and I just replaced my last battery after 6 years without ever having to clean the terminals or jump start the car.
--
If it needs to be maintained, repaired or replaced on a 1990 240, I've probably done it. '90 240DL, 254K looking forward to 300K badge (or sticker??). >>You haven't really worked on a car until you draw blood<< :-}

Thanks to you all.

Dale

2 different types of plate materials for positive and negative. Lead peroxide vs lead antimony if i remember correctly.
The negative plate always seemed to gather corrosion better than the positive plate. I think it is a oxygen and humidity thing combining with the particular lead alloy
In the five thousand or so batteries I have changed it was always the neg plate that gathered chalk.
Nasty stuff when it gets in your eye, up your nose or heaven forbid if you do not wash reallllly well before going to the washroom you will leave burning finger prints where fingerprints should not be.
--
73 ES, 91 240, 98 S90

I agree with Farm Boy regarding the battery being damaged. I think that happened to my previous battery since it would have the exact same type of buildup around the negative post. I would regularly pour a water and baking soda solution on it to neutralize the acid, only to have it reappear again. I've since bought a new battery and no leaking so far.

I did install one of those felt rings around the post which did slow down the leak.

If the battery is five years old or older, I'd consider replacing it. Also, check to see if any of the acid got into the battery cables. If so, replacing it may not be a bad idea. My battery cables were corroded so I replaced both of them.
--
Mike F - 1984 244 DL - 265,000 miles
Original engine, transmission, drive train, alternator, starter
Undergoing reconstructive surgery with POR-15

Sometimes overcharging will aggravate this situation. It might be worthwhile to do a voltage check
on the charging system. 13.5-14 volts is what you want. If it is more than that it uses up the water
in the battery and accelerates corrosion. I agree with the other guys- those felt rings work pretty well.
Be sure and put the red one on the + post.
--
George Downs, Bartlesville, Heart of the USA!

The battery is defective or was damaged when it was handled/installed.

There are seals around the posts where they pass through the case. If you pick up a new battery by the posts, or if you twist a post when tightening the clamp with a wrench, you will damage that seal and cause liquid acid and vapor to leak out around the post, corroding the clamp as you see here.

The best thing you can do now is to put on No-Co pads between the clamps and battery case, and/or seal the clamps using No-Co spray.

30 years ago, I used to use No-Co spray to seal the clamps on every battery I worked on, but I find that if everyone who handles the battery treats it with care, there is no need for No-Co.

As for cleaning it, Coke works, but bicarbonate of soda and water is a lot less sticky, and does not attract flies.

Just pull the cables, clean thoroughly with brush. I've heard Coca Cola is good too. Maybe replace the terminals or wires if it looks like the corrosion has gone into the wire itself... but if the car has been starting and seeming fine electrically, it's fine. You can get them anti battery terminal corrosion felt thingies at the parts stores (ask for that product exactly.. 'anti battery terminal corrosion felt thingies')... that might help.

You'll probably get better advice ffrom someone else.. I'm of the 'if it ain't broke, don't fix it' ilk... but definitely do clean things up. Watch your clothing.. any of that stuff gets on your clothes will turn into holes. Don't rub your eyes with that on your hands.. all that safety stuff. It's nasty.



--
-Matt I ♥ my ♂