2009-2010 Honda CRF450R – Front Caliper Service

Jun 22, 2018

How To Service The Front Brake Caliper On Your 2009 – 2010 Honda CRF450R

The Tools You Will Need Are:

The Parts You Will Need Are:

This front caliper rebuild on your 2009-2010 Honda CRF450r should cost around $25 and take about 45 minutes to complete.

Pre-Service Notes

Remove the brake pad pin plug, followed by the brake pad pin, and remove the brake pads, but leave the front caliper mounted.
Pump the brake lever to extend the pistons, using the brake disc as a backstop.
If you take your caliper off the fork and pump the pistons out, they may not extend evenly, like this one.
When the pistons have reached the brake disk, remove the banjo bolt, then remove the front caliper.
Make sure to wrap the end of your brake line with a paper towel.

If your pistons are hard to remove, you can CAREFULLY remove them with pliers wrapped in electrical tape.
Remove the slide pin boots, bleeder valve, and piston seals.
Be very patient when removing the piston seals.

Clean All Front Caliper Components
1. The components need to be free of brake cleaner residue before assembly.
2. You can wash everything down with brake fluid and a clean towel, or you can rinse and scrub with water. I don’t recommend using water unless you have compressed air to completely dry the front caliper body.

Inspect
1. Check the caliper components for any signs of noticeable wear or damage.
2. One of these pistons is pitted, so I will need to sand that down.
3. Check the slide pins for any rough areas that could bind. If you feel anything, gently sand it with fine-grit emery paper until smooth.

Measure
1. Measure the inside diameter of the piston bore and the outside diameter of the piston.
2. The piston bore should be no Greater than 27.060mm, and the piston should be no LESS than 26.853mm.
3. If your front caliper bore and pistons are out of spec, they need to be replaced.

Before assembly, take stock of your new parts. Do you need parts?
I am installing an All Balls rebuild kit that includes a new set of slide pin boots, bleeder valve cap, pistons seals, banjo bolt seal washers, and slide pin.
Make sure to match the old parts with the new ones, so you don’t throw away something you need.
Soak your new piston seals in fresh brake fluid for 15 minutes before assembly.

Give the caliper bore one last wipe just to be safe.
Install the piston seals, immediately followed by the pistons.
Make sure your pistons are aligned as flat as possible, then install them in a twisting motion.
Install the slide pin boots, the short boot goes on the bracket, and the long boot goes on the body.
Install the bleeder valve cover, then the bleeder valve.
Grease the slide pin boots with rubber grease, assemble the bracket and body, and give the bracket a few pumps to evacuate any trapped air in the boots.
If everything feels smooth, pull the bracket off and install the brake pad retainer, then reassemble the front caliper.