When to replace your volvo brake caliper.
A disc brake is a type of brake that uses a caliper set to squeeze pairs of pads against a disc in order to create friction that retards the rotation of a shaft, such as a vehicle axle, either to reduce its rotational speed or to hold it stationary. The energy of motion is converted into waste heat which must be dispersed. Hydraulic disc brakes are the most commonly used form of brake for motor vehicles but the principles of a disc brake are applicable to almost any rotating shaft.
Compared to drum brakes, disc brakes offer better stopping performance because the disc is more readily cooled. As a consequence discs are less prone to the brake fade caused when brake components overheat. Disc brakes also recover more quickly from immersion (wet brakes are less effective than dry ones).
MVS Forum Member Sinika74 asks:
Hey guys, Im a newbie and I gotta say that this is the best Volvo site Ive come across. Ok, last night I was in the middle of changing the front pads on my wife’s 93′ 940 and noticed that when I turned the front drivers side brake disk, I could hear the caliper grinding on the disk. Granted, the pads were wore down about as much as they could be. The front passenger side had the same problem, just not as loud. Does this mean that the caliper is dragging? Can I buy a rebuild kit? After noticing that, I did not install the pads but I left the car on the jacks with the tires off and forgot to lock the doors. Well, guess what? Now the radio is gone and whoever did it, cut the factory plugs as well. Now there is just a big hole with a bunch of wires and a din plug. I looked around MVS for a schematic and found one but it was for a 95′ 850. Does anyone know where I can find a schematic for a 93′ 940…minus the plugs would be nice, if possible. What does that din plug do anyways? Any and all help would be GREATLY appreciated.
MVS Forum Member billofdurham replied:
Hey, you’re like me. If you didn’t have bad luck you would have no luck at all!!
Are you sure it was the calipers catching the disc and not the metal backing of the pads? That is more likely.
Obviously you will be pushing the pistons back into the caliper so you will see if they are sticking if you have difficulty. You will also be lubricating all the other moving parts of the caliper so, again, you will see if anything is stuck. Make sure all moving parts are well cleaned of rust and dirt. For lubricating slides etc I prefer a copper grease.
As far as rebuild kits I have always kept away from them because the caliper has to be removed to the bench to rebuild it and, invariably, the bleed valves will snap off when you try to open them. I find it easier, cheaper and safer to fit new calipers.