840 Brake Discs and Pads - Help needed
Discussion
It should be pretty easy.
I always remove the complete caliper via 2 bolts on the back, circa 16mm, and then pry the caliper about a little if it needs to get over a lip at the edge of the disc.
Once the caliper is clear, flip the pads out, and you then can either fit the new ones in, or start by pushing the piston back. Either a g-clamp, or just a some sort of lever will do it, you'll need a steady constant pressure and they'll retract at their own pace.
The discs will have a retaining screw which will probably be the worst bit, as these are allen keys that like to round off.
Oil it at the first oportunity while you are getting the calipers off to help.
If needs be, you can either cut a slot in a stuck screw, or hammer a torx bit in if it rounds to get it out. They are vital, they just stop the disc coming off if the wheel isn't there.
A bit of copper grease will come in handy, a little on the back of the pads will help prevent squeal, and also put a little on the retaining screws if they come out OK.
Some people put a little copper grease on the hub face/back of disc, but you need to only have the slightest greasy feel left on it. Wire brush it and rub a little in, but any blobs of grease can make the disc sit at an angle and you'll get a pulsing through the pedal.
Once you have done one side, jump in and press the brakes, this will put the pads back in contact with the disc. Sometimes, if you have both or all calipers pushed back as far as they can go, the fluid reservoir will overflow, so this cuts down on the risk.
You should be good to go, other basics are clean the disc with white spirits, and a quick buff with coarse sandpaper to remove any oil they put on them to stop them rusting.
If you have some hammerite, you might as well paint the bell (the bit you'll be able to see between where the wheel sits, and the inner bit of the disc.
Good brakes tend to rust quick, so this keeps them looking clean.
I always remove the complete caliper via 2 bolts on the back, circa 16mm, and then pry the caliper about a little if it needs to get over a lip at the edge of the disc.
Once the caliper is clear, flip the pads out, and you then can either fit the new ones in, or start by pushing the piston back. Either a g-clamp, or just a some sort of lever will do it, you'll need a steady constant pressure and they'll retract at their own pace.
The discs will have a retaining screw which will probably be the worst bit, as these are allen keys that like to round off.
Oil it at the first oportunity while you are getting the calipers off to help.
If needs be, you can either cut a slot in a stuck screw, or hammer a torx bit in if it rounds to get it out. They are vital, they just stop the disc coming off if the wheel isn't there.
A bit of copper grease will come in handy, a little on the back of the pads will help prevent squeal, and also put a little on the retaining screws if they come out OK.
Some people put a little copper grease on the hub face/back of disc, but you need to only have the slightest greasy feel left on it. Wire brush it and rub a little in, but any blobs of grease can make the disc sit at an angle and you'll get a pulsing through the pedal.
Once you have done one side, jump in and press the brakes, this will put the pads back in contact with the disc. Sometimes, if you have both or all calipers pushed back as far as they can go, the fluid reservoir will overflow, so this cuts down on the risk.
You should be good to go, other basics are clean the disc with white spirits, and a quick buff with coarse sandpaper to remove any oil they put on them to stop them rusting.
If you have some hammerite, you might as well paint the bell (the bit you'll be able to see between where the wheel sits, and the inner bit of the disc.
Good brakes tend to rust quick, so this keeps them looking clean.
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