Hey Brian - thanks for chiming in!

I was aware of this part, especially since it's only a buck and change... But without having inspected the state of the wiring myself, I can't tell for sure if the dealer was referring to the harness cable or the sensor itself.

I'm guessing that this sensor/cable can be replaced by itself later if need be without tampering without having to remove pads or anything like that?... From what I understand, it goes OVER the caliper and not through/inside it?

__________________
84 300SD - bought in April '06 with 237,000 mi

Correct. The sensor cable can be replaced at anytime...........or not. It's only used for the warning light when the pads get down to minimum thickness.

Thanks again, I coulda looked that up, sorry.
Anyway, you see at the top of the pads a hole for those small one time use sensor wires. Also a shot of the back, you see the round part, put some anti squeal grease there and just above the pointer, on the metal "frame" only front and rear of the pad. Some cars have shim plates that fit on the back which should help with squealing also.

The cable harness bolts to the back of the hub.

Attached Thumbnails

   

__________________
83 SD

84 CD

Thank you for useful pointers.

I got the Duralast pads at Autozone today, and they do have that hole drilled into top side, so everything seems consistent!

What's the spec torque for lug bolts?

__________________
84 300SD - bought in April '06 with 237,000 mi

110 Nm, here's chart. I do 85 ft. lbs.
Or have the shop use a yellow torque stick.

Attached Thumbnails

 

__________________
83 SD

84 CD

I replaced front brake pads today! Thankfully, I did not notice any leaks on calipers at this time.

The pads I removed should have tripped wear sensors, if the sensors were working, as 2 pads (inner ones) were ground down about half-way across that little hole in a pad where sensor lead goes.

Turns out, sensor harness cables are bad on both sides! I do not know how they got mucked up this bad, but the cables are severed near their spindle mounting. As I said, the dealer alerted me to this, while Brian suggested it could simply be damaged sensors - unfortunately it's the $50-a-piece cables. The previous owner must have somehow messed those cables up because this is the first front brake job in 3.5 years that I had the car.

I ended up installing pads without sensors because what's the point with the cables broken... When I have money, I will fix this as it was meant to be :-P

__________________
84 300SD - bought in April '06 with 237,000 mi

Brake pad wear sensors are for folks who are completely out of tune with their vehicles. And I am sure that applies to the vast majority of owners. Personally, I would not spend even $10 to make the thing work. If you check the pads at every 6000 mile tire rotation, you will never be surprised by excessively worn brake pads.

Now that I did the job, I would like to ask how other people reset caliper pistons to make room for new pads.

For outer pads, I used the flat part of a curved pry bar to leverage against inner part of the rotor (where it doesn't wear) and the blade of the pry bar against the back plate of an old pad. For the inners, I leveraged the pry bar against where the clips would sit on the caliper (there is a clip-retaining bump) and put the blade against the back plate of the pad.

This took a few tries to get proper clearance. Are there better ways to reset pistons on these cars? Anybody use a C-clamp to do this? Personally, I couldn't see how that would be done - too little surface to leverage against.

__________________
84 300SD - bought in April '06 with 237,000 mi