How To Service The Rear Brake Master Cylinder On Your 2009 – 2010 Honda CRF450r.
The Tools You Will Need Are:
- 12mm Socket
- 7mm Socket
- 12mm Wrench
- 10mm Wrench
- 8mm Wrench
- 8mm Hex
- 5mm Hex
- Small Pick
- Stiff Brush
- Long Nose Snap Ring Pliers
- Torque Wrench
- Shop Towels
The Parts You Will Need Are:
- ’09-’10 Honda CRF450r Rear Master Cylinder Rebuild Kit
- Dot 4 Brake Fluid
- Rubber Grease
Brake fluid will damage almost everything it touches, so make sure you have your shop towels handy!
Clean And Inspect:
Scrub every part inside and out with brake cleaner and a shop towel.
Inspect every component for damage or uneven wear.
If you find any rough spots, gently sand them down with fine-grit emery paper.
Measure the inside diameter of the cylinder bore and the outside diameter of the piston.
The cylinder bore should be no Greater than 9.575mm, and the piston should be no LESS than 9.465mm.
If your cylinder bore and piston are out of spec, they need to be replaced.
New Rear Master Cylinder Parts:
Before assembly, take stock of your new parts.
I am installing an All Balls Rear Master Cylinder Rebuild Kit that includes a new pushrod boot, banjo bolt seals washers, piston cups, spring clip and piston spring.
Rear Master Cylinder Assembly:
|(Click to Enlarge)|
|Start your assembly with the piston. Install the piston cups with the large side facing the spring end.|
Take your time with the cups; if they are damaged during install, your brakes won’t work.
|Install the piston spring.|
|Coat the master cylinder bore with brake fluid, and install the piston past the first cup.|
Install the piston in a twisting motion to avoid rolling the cups.
|To install the pushrod, start by holding the cylinder body with your left hand.|
Apply a layer of rubber grease to the pushrod, then position the push rod and spring clip.
|Firmly press the pushrod down with your left thumb, and clip the pushrod into place.|
|To make sure the clip is in the groove, use your pick to rotate it. If it moves, it’s seated.|
|Apply some rubber grease to the inside of the new boot, and slip it over the pushrod.|
Push the boot into place with the round side of your 8mm wrench, and make sure the top of the boot seats in the groove past the nut.
Wipe off any excess grease.
|Install the diaphragm and reservoir cap.|
Rear Master Cylinder Installation:
|Install the banjo bolt with the new seal washers, and make sure the shank rests on the tab.|
|Install the master cylinder mounting bolts.|
|Install the brake lever and attach the return spring. After your rebuild, make sure to bleed the rear brake system!|
Rear Master Cylinder Torque Specs:
|Mounting Bolts||10 ft-lbs|
|Banjo Bolt||25 ft-lbs|
|Pivot Bolt||27 ft-lbs|
Keep Your ’09-’10 CRF450r Running Right!
- Service Specification
- Clutch Replacement
- Fuel System Service
- Engine Top End
- Front Suspension & Steering
- Rear Suspension
- Wheels & Tires
- External Shift Linkage
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