w116 300sd Mercedes Hard to brake
- Thread starter Gito
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Yes first I'd consider that the booster is not working. Is this a vacuum system? If it is, test by noticing if the pedal is easier to press with the engine running than with it off. The first 2 or 3 presses after turning the engine off should be normal, then it should get hard.
Pad stops-- that sounds like fun. Leave the poor guy with no brakes instead of metal on metal, which will at least stop the car, at the cost of ruining the rotors.
When you put on new rotors, you must first clean the friction surfaces with brake cleaner. They have some sort of coating to prevent rusting during storage. If not removed, it will transfer to the pads and reduce friction.
Hydraulic problems will almost all make the pedal go to the floor without the car stopping much. If the pedal does not go to the floor, hydraulics are likely OK and the problem is something else.
Pad stops-- that sounds like fun. Leave the poor guy with no brakes instead of metal on metal, which will at least stop the car, at the cost of ruining the rotors.
When you put on new rotors, you must first clean the friction surfaces with brake cleaner. They have some sort of coating to prevent rusting during storage. If not removed, it will transfer to the pads and reduce friction.
Hydraulic problems will almost all make the pedal go to the floor without the car stopping much. If the pedal does not go to the floor, hydraulics are likely OK and the problem is something else.
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Originally Posted By: mk378
Pad stops-- that sounds like fun. Leave the poor guy with no brakes instead of metal on metal, which will at least stop the car, at the cost of ruining the rotors.
Yes, his symptoms reminded me of the first time I came across them, a hard pedal and very little stopping power. The pads were worn, but not what I would've considered worn out back then. After checking everything else, I returned to the pads and found the spring backing for the pins was a pad stop. Even my W202 has them on the rear, but wear indicators on the front.
Pad stops-- that sounds like fun. Leave the poor guy with no brakes instead of metal on metal, which will at least stop the car, at the cost of ruining the rotors.
Yes, his symptoms reminded me of the first time I came across them, a hard pedal and very little stopping power. The pads were worn, but not what I would've considered worn out back then. After checking everything else, I returned to the pads and found the spring backing for the pins was a pad stop. Even my W202 has them on the rear, but wear indicators on the front.
Originally Posted By: mk378
Yes first I'd consider that the booster is not working. Is this a vacuum system? If it is, test by noticing if the pedal is easier to press with the engine running than with it off. The first 2 or 3 presses after turning the engine off should be normal, then it should get hard.
Pad stops-- that sounds like fun. Leave the poor guy with no brakes instead of metal on metal, which will at least stop the car, at the cost of ruining the rotors.
When you put on new rotors, you must first clean the friction surfaces with brake cleaner. They have some sort of coating to prevent rusting during storage. If not removed, it will transfer to the pads and reduce friction.
Hydraulic problems will almost all make the pedal go to the floor without the car stopping much. If the pedal does not go to the floor, hydraulics are likely OK and the problem is something else.
I stopped cleaning the primer looking coating on rotors years ago. Hope that isn't the issue.
All of my rotors for all of my Mercedes cars have always come with that coating.
The coating on the front and back rotors is now gone, after driving only 20 miles so far.
Does that coating eventually dissipate or burn off from the pads?
Yes first I'd consider that the booster is not working. Is this a vacuum system? If it is, test by noticing if the pedal is easier to press with the engine running than with it off. The first 2 or 3 presses after turning the engine off should be normal, then it should get hard.
Pad stops-- that sounds like fun. Leave the poor guy with no brakes instead of metal on metal, which will at least stop the car, at the cost of ruining the rotors.
When you put on new rotors, you must first clean the friction surfaces with brake cleaner. They have some sort of coating to prevent rusting during storage. If not removed, it will transfer to the pads and reduce friction.
Hydraulic problems will almost all make the pedal go to the floor without the car stopping much. If the pedal does not go to the floor, hydraulics are likely OK and the problem is something else.
I stopped cleaning the primer looking coating on rotors years ago. Hope that isn't the issue.
All of my rotors for all of my Mercedes cars have always come with that coating.
The coating on the front and back rotors is now gone, after driving only 20 miles so far.
Does that coating eventually dissipate or burn off from the pads?
Originally Posted By: Gito
I stopped cleaning the primer looking coating on rotors years ago. Hope that isn't the issue.
All of my rotors for all of my Mercedes cars have always come with that coating.
The coating on the front and back rotors is now gone, after driving only 20 miles so far.
Does that coating eventually dissipate or burn off from the pads?
He's talking about the preservative oil that typical rotors come covered with. The "primer" you're talking about is typical on European cars and no, you do not have to clean it off.
I stopped cleaning the primer looking coating on rotors years ago. Hope that isn't the issue.
All of my rotors for all of my Mercedes cars have always come with that coating.
The coating on the front and back rotors is now gone, after driving only 20 miles so far.
Does that coating eventually dissipate or burn off from the pads?
He's talking about the preservative oil that typical rotors come covered with. The "primer" you're talking about is typical on European cars and no, you do not have to clean it off.
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