XUI3536A Clutch master cylinder

CM246

Parameter Item	Specifications
Product Number	(XUI) XUI3536A
OE Number	31410-20061
Inner Bore Diameter (DIA)	15.87 mm
Mounting Size	Φ30 / 60 / 2-M8×1.25 (bolt fixing)
Hydraulic Connection Specification (Connecting Size)	M10 × 1.0
Mounting Method	Bolt fixing
Applicable Brake Fluid	DOT 3 / DOT 4
Cylinder Body Material	Cast Iron
Seal Material	Hydraulic-resistant Rubber
Packaging Method	Neutral Packaging / OEM Custom Packaging Available

The clutch master cylinder is the core hydraulic component of the clutch system in a manual transmission vehicle. When the driver depresses the clutch pedal, the master cylinder converts this force into hydraulic pressure, which pushes the slave cylinder through the pipeline. The slave cylinder then disengages the clutch, allowing the gear shift to complete. Simply put, without the master cylinder, pressing the clutch pedal is like leaving nothing in the way—the vehicle cannot shift gears or move.

Compatible Models: 1964–1970 Toyota TR40 / RT-80
The Toyota TR40 / RT-80 (1964–1970) were light commercial and off-road platform vehicles produced by Toyota in the 1960s. They featured a body-on-frame construction and were known for their mechanical simplicity and high durability. These models were mainly distributed to Southeast Asia, the Middle East, Australia, Japan, and the Pacific region, where they were widely used for agricultural transport, mining operations, and light engineering.

Due to their simple structure and low maintenance requirements, a considerable number of these 1960s Toyota vehicles are still in service in rural areas of Southeast Asia and Australia, while some have been preserved and restored by collectors as classic cars. Both of these usage scenarios generate real demand for parts: the former is for actual repair needs, and the latter is for collection and repair purposes.

This master cylinder serves this highly segmented but genuinely demanding market.

Core Function: Three parameters determine whether it can be installed and how well it works.

The inner bore diameter of 15.87mm is the most critical dimension of this master cylinder. The inner diameter of the clutch determines the hydraulic output force during the piston stroke, which is the feel of the pedal. The clutch systems of the TR40 and RT-80 are relatively light; 15.87mm is the standard size for this hydraulic stroke design, smaller than the 19.05mm of later models (such as the J9/J12). They cannot be interchanged; incorrect specifications will result in abnormal pedal feel or, worse, insufficient hydraulic pressure to drive the slave cylinder.

The installation method is bolt fixing (M8×1.25 bolt). The installation dimensions Φ30/60/2-M8×1.25 correspond to the bolt hole positions of the master cylinder mounting bracket on the TR40/RT-80 body. This is a typical installation structure of Toyota models from the 1960s, different from the clip or pin installations commonly found in modern models. When purchasing, pay attention to the mounting hole spacing and bolt specifications; both must be perfectly matched for a secure fixation.

The hydraulic interface M10×1.0 is the thread specification for connecting the hydraulic line to the master cylinder. If this interface specification is correct, it will form an effective seal after installation, preventing hydraulic oil leakage and system pressure loss. M10×1.0 is the standard interface for the hydraulic lines of this model. If your spare lines or connectors are of different specifications, you need to confirm in advance whether you need an adapter.

What problems can this product solve for buyers?
The supply of parts for classic cars and older work vehicles is one of the least competitive yet most customer-loyal subcategories in the auto parts market. The reason is straightforward: people willing to repair a 1960s Toyota, whether for actual use or for collection and restoration, have a strong sense of purpose and loyalty to this model. They won't switch brands for a few dollars' difference in price—they just need to find the parts and have them installed and work.

For parts dealers focusing on the Australian, Southeast Asian, and Japanese classic car markets, the original factory number 31410-20061 is itself a search term for their target customer group. Dealers who can reliably supply parts corresponding to this number will build a strong reputation among local repair shops and collection/restoration circles, resulting in extremely high repurchase rates, but this is contingent on stable supply and consistent dimensions.

For independent brand operators looking to penetrate the classic car parts category, the pricing logic for these products is completely different from mainstream modern car parts—it's not about competing on low prices, but on reliability and stable supply. If your brand can establish a reputation for being "findable, installable, and reliable" in this niche market, it's easier to build a brand barrier than selling generic parts in a red ocean market.

For multi-brand classic car parts distributors, the logic behind this product is to complete their SKU matrix. Older Toyota models still have a real presence in Australia, New Zealand, and Southeast Asian island nations. If you're already selling other parts for Toyotas from the 1960s and 70s, adding this master cylinder allows your customers to purchase more parts from one place, eliminating the need to source from multiple suppliers.