I've just noticed that the battery on my '78 280slc was over charged, and after a little investigation my voltage regulator is supplying over 16v at idle to the battery, and over 17v at 2000(ish) rpms.
My understanding is that I need a new voltage regulator, but on the Pelican Parts site they list short an long types of voltage regulators.
The EPC lists them based on the alternator number, but I cannot find any number on my alternator body (I have not removed it from the engine, though).

So my question is: do I need a short or a long brush regulator?

EDIT: forgot to add: my voltage regulator number is 0 192 052 008 EE

Take it apart and measure, don't drive the car as you are _GOING_ to damage electronics and the battery.

Alternator is the problem and not the regulator .

Doubtful.

If the regulator fails in a full-output condition, high voltage is the result. Typically 16-18V for most automotive applications. Very fast way to ruin a battery and do catastrophic damage to anything solid-state in the car.

The OP should probably add an OVP relay to their shopping list. If it worked and did its job, it's probably damaged by now.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

So about the short or long thing: after some googling, I found out that there are two commutator (the thing the brushes ride on) sizes, 28mm an 32mm.
If you have the 32mm (my case) you need the short brush type, and vice versa. Taking the regulator out of the alternator body does involve some mechanic's Yoga, though.

I wont drive the cat util the new regulator arrives. The only electronic device on this car is the ignition module. For curiosity's sake, I took it apart and it looked pretty clean, no burned marks or anything (see attached pic).

In my understanding, when alternators fail they normally don't generate enough voltage, if at all. I have the opposite problem, too high voltage.

I forgot about the OVP. Thanks.

Attached Thumbnails

 

Please expand on this.