280SEL electical problem

Hi,

I just picked up a 1970 280SEL yesterday. It is in beautiful condition, with only 73,000 miles. This body style has long been a dream car for me, and my wife and I put almost 100 miles on it last night. We love the car.

But I have already ran into my first problem. I was just getting home today, when I heard ignition noise in the radio. It got worse, until it drowned out the radio station. Then I noticed that the wipers (there was a heavy rain) seemed to be running slow. As I backed into my parking place, the engine quit and would not turn over. The car had no electrical power. I tried to start if for a couple of minutes, and noticed that accessories came back to life. However, it still won't turn over. What gives? I appreciate any input.

I also have a slight brake problem. The cars pulls to the left during hard braking. Otherwise, they are just fine. This seems to be an adjustment problem. My Haynes manual states that the brakes are self adjusting. I remember that on US cars of this vintage, you could adjust the brakes by driving backwards and braking several times. Will the same tactic work in this case?

You can also E-mail responses to CostaTravl@aol.com.

Thanks! I appreciate your kind assistance.

Pat in New Orleans

[Mark DiSilvestro]

You need to charge the battery, then check why the alternator isn't charging (Loose belt, Bad alternator/regulator, wiring?)
That 'back up to adjust' is for drum brakes. You have 4 wheel disc brakes which should 'self adjust' during normal driving/braking. You could have a sticking brake caliper or blockage in a rubber brake hose. Hope this helps.
Happy Motoring, Mark DiSilvestro

[Aaron]

I agree with Mark. Check the alternator for output and check the belt, etc..

On the brakes, I'd amost bet it's a rubber hose. I always recommend to my customers they they replace all four rubber hoses while under there. They're not expensive and last a long time. Hell, I just replaced all of them on my '77 450SL which has 170K on it and all hoses were original. And of course, when you replace the hoses, it's always a good excuse to change the brake fluid

Remember to use a good DOT 4 type, such as Ate SL

[cth350]

Your car has a voltage regulator external to the alternator. Follow the 3 prong connector at the back of the alternator and its wiring will go to the regulator. It's a metal can about 3" x 3" x 2" and has a colored stripe of tape. You can replace it with a junk yard one, presuming it has the same color tape (yellow, which fades white, or light green).

The alternator can't charge if the generator light doesn't first go on as you turn the key. Once you boost the battery on a charger a bit, make sure the light goes on.

WARNING: the thick wire(s) at the back of your aternator carry 12v at all times. Do NOT get a wrench back there without first disconnecting the battery. You will have an awful mess on your hands should you make a mistake.

As for the brakes, check the dates on the rubber hoses. The hoses should be less than 5 years old. Most likely, they are old and have swelled, keeping the fluid from releasing back to the master cylinder. Be sure to replace them and the little metal clips that hold them in place. You will need to pick up a decent set of flare wrenches from sears for this job.

Lastly, get a real service manual. You can find the manual for passenger cars starting 1968, 108 109 111 113 on ebay for about 30$. Brand new, it's not much more than that and still available. You can also find it on CD.

-CTH

My experience with European cars is that the ground wires corrode and build up oxide. Make sure that the battery is sufficently charged. Clean the negative battery post and the internal portion of the terminal clamp. Then try to start it. If it is still weak, put a jumper cable from the negative battery clamp over to the alternator bracket. (make sure it is clear of the fan) and then try it. If this clears up the problem then you either need to put a new clamp on the cable, or clean or replace the end that connects to the chasis.

Good luck

Thanks for the input. It is pretty neat to be able to go on the net and have all of these experts give me their insight. I appreciate the time you all have spent on this for me.

On further review, we found that this was a combination of two problems.

The battery cables were loose, and the negative had one of those aftermarket replacement clamps. The connection at the chassis was badly corroded as well. I cleaned everything up and replaced the cable. There was an immediate improvement.

However, I noticed that the headlights seemed a little dim. A friend (who is a Mercedes addict. Incurable, I'm afraid) told me about a local mechanic that specializes in german cars, particularly electrical. He ran some tests, and determined that the alternator was fine, but the voltage regulator needs replacing. I am bringing it back on Monday for this, and to have him check out the brakes.

Again. Thanks alot for the input.

Pat in New Orleans