Jake,

I'm afraid I can't tell you what's causing the jerking movement based on what you've described, but I think I can say that it's probably not caused the new brakes. There are a number of quite good aftermarket (non-genuine MB) brake pads that work just fine, and none that I can think of that would, in and of themselves, cause any kind of problem like the one you're describing. If you can give a more complete description of the symptoms it would be helpful in determining what some of the possibiities might be.

For example, by "jerking" do you mean a repetitive forward and backward motion that the whole car goes through as if there's a big rubber piece in the driveline that is flexing and unflexing, or perhaps just a slight pause followed by a "clunk" and then a feeling of decelerating?

In regards to your battery, you might want to consider doing the following:

Go to Sears and buy an automatic battery charger, a couple of those felt corrosion inhibitor rings that go on the battery posts, a battery terminal brush and an automotive battery hydrometer to test the specific gravity of the electrolyte. Try to find one that has a glass tube inside of a glass or plastic bulb syringe and reads specific gravity by numbers, such as 1.280 for fully charged, 1.240 for 75% charged, etc. If Sears doesn't have one, check any auto parts store or on the web. If your battery is the sealed type, i.e. it doesn't have removable vent caps on top, don't worry about the hydrometer. I would also recommend buying a BatteryMINDer (About $40). In addition to keeping the battery fully charged at all times you can also use it to keep power applied to the the car's electrical system when you disconnect the car's battery for charging. If you lose all power to the car for more than a few seconds you may lose some stored electronic information, such as the radio code.

If your present battery is not a sealed type, carefully remove the top caps and see where the water level is. It should be right up to the bottom of the hole. There's usually a slot on one side of the hole and when the electrolyte level reaches the bottom of the slot you can see the liquid surface suddenly change from flat to radiused at the edges. Use only distilled water to fill the cells, if needed, and do not overfill. Before filling, tip the battery to one side slightly, lift it about an inch or so and tap it on the bench (or wherever you've got it sitting) to loosen any trapped gas bubbles under the plates inside that might make it look fuller than it is.

After filling, use the hydrometer and check the reading. If it's less that 1.280, put the battery on the charger, following the instructions that come with it, until it indicates full charge. Be sure to check each cell individually, as they can vary depending on the condition of the plates in that cell. Also, keep an eye on the temperature. During charging the battery temp may rise as much as 25 deg. F. If it's much more that that, it may indicate a charge rate that's too high or possibly a shorted cell. Another reason for checking specific gravity of each cell periodically.

Initially, the charge rate may be quite high, upwards of 8 to 10 amps. This should taper off to about 4 amps within a couple of hours and down to as little as 2 amps toward the end of the charge cycle.

During charging the battery can release bubbles of hydrogen gas which is very explosive . Don't let any sparks or open flames come within 5 ft of the battery. These bubbles can also cause the electrolyte level to rise, so the "tipping and tapping" routine should be done every several hours.

The full charge cycle can take as long as 8 to 12 hours. After charging, let the battery sit for several hours to cool down. Once it's finished, wipe off any liquid electrolyte that may have collected on the outside of the battery, being aware that it contains sulfuric acid. Even a drop on your cothing (especially cotton jeans) will leave a nice little hole next time you wash them. Wear rubber gloves to protect your hands and immediately wash any part of your skin that comes into contact with it with lots of water.

Reinstall the battery in the car, clean the battery posts and cable terminals with the terminal brush, install the corrosion inhibitors and attach the cables, positive (+) cable first, negative (-) cable last. Start the car and recheck the charging system to make sure that you get 13.5 to 14.5 volts at the battery terminals.

The BatteryMINDer leads can be permanently attached to the battery and plugged into the BatteryMINDer whenever the car will be sitting for an extended amount of time, or as often as you like. It can't hurt the battery, only help it last longer. I've been using several on my cars and motorcycles for a number of years now with excellent results. It works especially well for the deep cycle battery in my little pop-up camper, which doesn't get used for months at a time and then gets used for 5-7 days straight without charging.

Hope this helps.

Gary

P.S. - Here's a link to the BatteryMINDer Owner's Manual . It gives a good description of how it works and some general information on charging flooded lead acid batteries (your typical car or motorcycle battery). Also, I've dealt with BatteryWeb.com several times and would recommend them without hesitation. I have no connection with them other than being a satisfied customer.