Disc Brake Service
Replacing your front brakes is not that difficult. However, there are a few key things to remember if you’re going to service them yourself.
One of the main mistakes I see people making when servicing disc brakes is not opening the bleeder valve when compressing the caliper piston. If you don’t open the bleeder valve when compressing the caliper piston, you can actually damage your master cylinder. This won’t happen all the time, but it only takes once to ruin your day. The master cylinder is designed to move brake fluid in one direction. Sometimes when you force brake fluid in the opposite direction through the master cylinder, you ruin its seals and cause it to fail. I’ve seen more than one occasion where someone did this, only to find they have no brakes or a very spongy brake pedal after replacing their brake pads. The fix is to replace the master cylinder.
To avoid all this, open the bleeder valve when compressing the caliper piston. It really doesn’t take that much effort and it potentially saves you the expense of having to replace your master cylinder in addition to the brake pads.
- Vacuum Brake Bleeder $48.95
Another common mistake I see is improper lubrication on the caliper slide pins. These are the pins that the caliper slides on when active. These pins are found on many brake calipers (but not all brake calipers).
The proper lubricant is silicone paste, not grease. Grease is petroleum-based and will eat away at the rubber boots on the slide pins. Once the rubber deteriorates it can cause the pins to bind and not move correctly. In addition to that, when the grease mixes with the silicone that should already be lubricating the slide pin, bad things happen chemically. In addition to all that, grease was never designed for the heat that your brakes produce, so it tends to dry up. After it dries up, the caliper slides don’t work and your brakes don’t work as well as they could.
In addition to grease, DO NOT USE ANTI-SIEZE to lubricate caliper slide pins. It’s probably the worst thing to use on caliper slides, because it dries up and causes the pins to seize. I know that sounds ironic considering the lubricant’s name, but it’s true. If you do have anti-seize on your caliper slides or any other lubricant that shouldn’t be there, clean the pins, the bores, and the inside of the dust boots thoroughly before using the proper lubricant. Failing to do so can cause issues with the lubricants mixing. Bad things can happen when you mix lubricants, so do your best to avoid it.
I get asked about other lubricants all the time, but I stick by my recommendation of 3M Silicone Paste. You can use other lubricants designed to lubricate caliper slide pins, but I recommend the ones that are silicone-based or synthetic, not the ones that are petroleum based. Here is a link to the silicone paste that I use.
That covers the main points about servicing front brakes. For more details on how I perform a disc brake service, watch this video.