Royal Enfield Rear Brake Master Cylinder – 13 mm (OE) for Himalayan 450 & Guerrilla 450 — RAB00463/D

Restore crisp rear-brake feel on your Sherpa-450 platform bike with the genuine Royal Enfield Rear Brake Master Cylinder — 13 mm (Part No. RAB00463/D). This factory unit matches the original bore size, porting, push-rod interface and electrical provision for the brake-light circuit, so it bolts straight onto the stock rear-set bracket and connects to the OE hose without adapters. Because it’s OEM, piston seals and return spring rates are tuned for ABS modulation on the Himalayan/Guerrilla 450, delivering progressive lever travel, consistent pressure and long service life in wet, dusty Indian conditions.

Fitment is confirmed on the Himalayan 450 (MY2024-on) and Guerrilla 450 (MY2024-on); both use the same Sherpa 450 braking architecture. Avoid universal “13 mm” pumps that can upset pedal ratio or leak at the banjo/bleed points — this OE assembly maintains factory safety and feel, and helps reduce returns. If your rear brake feels spongy, sticks, or fails to build pressure after a fall, replacing the master cylinder and flushing fresh DOT 4 often restores performance. Verified by the Royal Enfield fiche/dealer catalogs that list “MASTER CYLINDER, REAR, 13 — RAB00463/D.” 

Key Features

• Genuine Royal Enfield assembly — RAB00463/D “MASTER CYLINDER, REAR, 13.” 

• 13 mm bore matched to Sherpa-450 ABS tune for predictable feel. 

• Direct bolt-on to OE bracket and hose; no adapters needed. 

• OE seals/spring rates for durability in heat, rain and dust.

• Maintains correct pedal ratio & stroke; avoids universal-part pitfalls.

• Backed by trusted dealer listings for Himalayan 450 & Guerrilla 450. 

• Compatible with OE ABS hardware and brake-light circuit. 

Compatibility Table (confirmed only)

Exclusions: Not listed for Himalayan 411/Scram 411 or any 350/650 platforms in fiche for this PN. Order platform-specific parts for those bikes. 

Variants

Single variant currently published: RAB00463/D (rear, 13 mm). (Front master cylinder for Sherpa-450 is a different 14 mm assembly per fiche list.) 

FAQs

Q1. Will this fit my Himalayan 450?
Yes — this is the OE rear master cylinder (13 mm) for Himalayan 450. 

Q2. Does it also fit the Guerrilla 450?
Yes — dealer catalogs list RAB00463/D for Guerrilla 450 as well. 

Q3. What fluid should I use and how do I bleed it?
Use DOT 4 as per the owner’s manual and bleed the rear circuit after installation.

Q4. My pedal feels soft after a tip-over — will this fix it?
If the master piston/seals are damaged or contaminated, replacing with this OE unit plus a fluid flush usually restores pressure.