Girling remote reservoir master cylinder
Genuine Girling aluminum master cylinders designed to run a remotely mounted fluid reservoir, available in three bore sizes. Select your bore above. The non-integral casting is the one to choose when there is no room for a reservoir on top of the cylinder, when you want the fluid mounted higher for bleeding, or when a single reservoir is feeding more than one cylinder.
These are the master cylinders that were standard fitment on competition cars for fifty years, from the 1950’s through the 1980’s. They are perfect for formula and sports racer construction because of their compact size, light weight, and reliability.
Bore sizes and cross references
We list these under the genuine Girling part number stamped on the cylinder body. The bore size is also cast into the side of the casting, so you can identify what you already have without pulling it apart.
| Bore | Fractional | Metric ID | Girling part number | Cross reference |
|---|
| 0.625 in | 5/8 in | 15.875 mm | 64067651 | 3502-.62 |
| 0.700 in | 11/16 in | 17.78 mm | 64067884 | 3502-.70 |
| 0.750 in | 3/4 in | 19.05 mm | 64067620 | 3502-.75 |
Reading the casting: 0.625 in may appear as either 5/8 or 625, 0.700 in as either 7/10 or .70, and 0.750 in as either 3/4 or .75.
Specifications
| Specification | Detail |
|---|
| Manufacturer | Girlinggenuine, brand new, not remanufactured |
| Reservoir | None fittedtakes a remote reservoir, sold separately |
| Inlet port | 7/16-20 UNF, flat rear inletsame thread as 4AN |
| Outlet port | 3/8-24 UNF, 45° front outletsame thread as 3AN |
| Mounting centers | 2.25 in vertical57.2 mm, industry standard flange |
| Maximum stroke | 1.375 in35 mm |
| Pushrod | 5/16 in UNF, includedtypically 3.75 to 4.00 in from the mounting flange |
| Length from mounting face | 4.2 in107 mm |
| Circuit | Singlesuitable for brake or clutch use |
| Seal material | EPDMall DOT-rated brake fluids; not for hydraulic oil |
| Body material | Aluminumapproximately 340 g / 0.75 lb |
| Rebuildable | Yessee repair kits below |
| Sold as | One cylinderreservoir and inlet fitting not included |
Typical uses and applications
- Tilton 600 series pedal boxes, and most other pedal box designs on the 2.25 in flange pattern
- Formula and sports racer brake and clutch circuits
- Hydraulic handbrakes and hand-operated clutch assemblies
- Historic and vintage competition cars, where these were often original fitment
- Kit cars and specials — Caterham, Lotus Seven derivatives and similar
- Installations where the reservoir must sit high or remote for bleeding and fluid level visibility
Remote or integral
- Remote reservoir, this cylinder, has a 7/16-20 inlet port and no reservoir on the body. Choose it for tight pedal boxes, for mounting fluid high, or where one reservoir feeds several cylinders. Budget for a reservoir and inlet fitting on top of the cylinder price
- Integral reservoir carries a 1.75 in reservoir molded into the casting and needs no separate plumbing. Simpler and cheaper to install where there is room in front of the cylinder
Both share the same 2.25 in mounting centers, 3/8-24 outlet, 1.375 in stroke and 5/16 in UNF pushrod, so swapping between them is usually a matter of plumbing rather than pedal box modification.
Good to know
- You will need a reservoir. Nothing is included on the inlet side. See the reservoir options below, and note the inlet is 7/16-20 UNF, the same thread as 4AN
- Genuine, and it matters. Girling-pattern clones circulate widely and some cannot be rebuilt at all. Genuine cylinders carry GIRLING cast into the side of the body
- Choosing a bore. A smaller bore gives higher line pressure for a given pedal effort but needs more pedal travel. Larger bores move more fluid per stroke. If you are changing bore size to chase a pedal feel problem, talk to us first — it is often a balance bar or pad compound issue rather than cylinder sizing
- Mount the reservoir above the cylinder. Gravity feed is what keeps the cylinder full and makes bleeding straightforward
- Service them on a schedule. Reseal rather than wait for a failure. Front-running teams rebuild master cylinders at least once a season
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