Clutch Master Cylinder for Mazda B2000 B2200 B2600 B Series – XUI3018A

CM246

Vehicle Compatibility Overview

Vehicle Model	Production Years	OE Reference Numbers
Mazda B2000	1966–1987	UB39-41-400 / UB93-41-400
Mazda B2200	1987–1993	UB93-41-400 / UC86-41-400
Mazda B2600	1987–1993	UB93-41-400 / UC86-41-400
Mazda B Series (UF)	1985–1999	UB93-41-400 series
Mazda B Series (UN)	1999–2006	UC86-41-400 series

Cross Reference Numbers

Reference Type	Number Details
Part Model	XUI3018A
Cross Reference	CM246
OE (primary)	UB93-41-400 / 400A / 400B / 400C
OE (alt 1)	UC86-41-400 / 400A / 400B
OE (alt 2)	UB39-41-400
DORMAN	CM111151A
D-MAD	DM53411

 Technical Specifications

Item	Specification Value
Model	XUI3018A
Bore Diameter	15.87 mm
Mounting Size	Φ29 / 60 / 45° / 2-M8×1.25 (bolt)
Connecting Size	M16 × 1.5
Installation	Direct replacement
Packaging	Neutral box / OEM custom branding

Clutch Master Cylinder for Mazda B Series — Four Decades of Pickup Coverage
The Mazda B Series pickup ran from the mid-1960s through 2006 across two distinct platform generations (UF and UN), spanning B2000, B2200, and B2600 engine variants. XUI3018A covers this entire range under a single part number — one of the broadest single-SKU fitment windows in the Mazda pickup aftermarket.
Original OE references for this component went through multiple revision suffixes (400 → 400A → 400B → 400C), all superseded by the same physical unit. XUI3018A is manufactured to the final superseded specification, ensuring direct installation without compatibility concerns across the full production run.
The clutch master cylinder on B Series pickups is firewall-mounted and directly coupled to the pedal assembly. These vehicles were designed for working use — commercial hauling, agricultural applications, and daily utility transport — meaning the clutch system sees higher actuation frequency than typical passenger vehicles. This accelerates seal wear over time, particularly on high-mileage units that have not had hydraulic fluid changed at recommended intervals. Degraded fluid accelerates internal corrosion and seal swelling, both of which reduce bore sealing efficiency and shorten component life.

Common failure signs on B Series pickups:
Clutch pedal sinks slowly to the floor under sustained pressure — internal bypass past worn piston seals
Fluid loss from reservoir with no external drip — seal failure consuming fluid internally
Pedal feel changes noticeably between cold start and operating temperature — heat-sensitive seal degradation
Clutch won't fully disengage after highway driving — pressure bleed-off under sustained thermal load

Identifying these symptoms early prevents secondary wear on the slave cylinder and release bearing — components that can be damaged when the master cylinder delivers inconsistent or insufficient pressure over an extended period.

Market Application
North America — B2200 and B2600 remain active in the classic truck and restoration market; DORMAN CM111151 drives consistent Amazon and catalog demand across AutoZone, RockAuto, and O'Reilly channels
Australia & Southeast Asia — B Series UF and UN were strong sellers across Australia, Thailand, and the Philippines; independent workshop demand continues as these vehicles pass 20+ years of service age
Latin America — B2000 and B2200 pickups remain in daily working use across Mexico, Chile, and Peru; aftermarket manufacturing is the only available supply channel for hydraulic clutch components on these platforms

Q1: The OE number has four suffix variants (400, 400A, 400B, 400C) — which one does XUI3018A replace?
All four. Mazda issued revision suffixes during production without changing the physical specification of the component. XUI3018A is manufactured to the final superseded specification and replaces all suffix variants directly with no fitment differences.

Q2: Does this fit the Ford Ranger that shares the Mazda B Series platform?
Some Ford Ranger variants — particularly the ER/EQ export platform built on Mazda B Series architecture — use the same clutch master cylinder specification. Verify against OE number UB93-41-400 or DORMAN CM111151 before ordering to confirm your specific Ranger variant is covered.

Q3: The bore is 15.87mm — smaller than many aftermarket cylinders. Does this affect pedal effort?
Yes, and this is an important fitment point. Bore diameter directly sets the hydraulic ratio between pedal effort and pressure output. The 15.87mm specification is correct for B Series models. Installing a larger-bore cylinder will produce a lighter pedal feel but reduce maximum pressure output — potentially causing incomplete clutch disengagement under load, particularly at low engine speeds.