Brake and Clutch Master Cylinders — 0.625″, 0.7″, 0.75″, 0.875″ and 1-inch Bore Sizes
The space-saving, integral design of the obp master cylinder is a game-changer for bulkhead-fit pedal boxes, making it perfect for installations where the cylinder sits conveniently in the engine bay. With the built-in reservoir, you eliminate the need for extra brake lines required in a remote setup, ensuring a leak-free operation and a cleaner, more efficient system.
The obp Master Cylinder is designed for compatibility, with a 2.25” (57mm) bolt-hole spacing that matches most standard mounting patterns in the industry. This makes it an ideal choice for a wide variety of applications, including automotive, motorsport, agriculture, hydraulic systems, and more.
Integral Master Cylinders Key Features
- Lightweight at just 350g
- Vertical Mounting Flange for easy installation
- 3/8”-24 UNF Outlet for reliable connections
- Standard 84mm Push Rod Length
- M8 Bolt Hole Size for universal mounting
Choosing the Right Master Cylinder Bore Size
When selecting the proper master cylinder size for automotive and motorsport applications, a general rule of thumb is:
- 0.625-inch Bore for front brakes
- 0.700-inch Bore for rear brakes
- 0.750-inch Bore for the clutch
- 0.875-inch or 1-inch
However, this may vary depending on the size of your brake calipers because some calipers require more brake fluid for optimal performance.
- Inlet Fitting: 7/16-inch-20 UNF
- Outlet Fitting: 3/8-inch-24 UNF
- Push Rod Thread: 5/16-inch
- Pushrod Length: 84mm
- Bolt Hole Spacing: 1/4-inch
To add some context, the 3/8”-24 UNF outlet indicates that the outlet port of the master cylinder has a diameter of 3/8 inches, with 24 threads per inch, following the UNF threading standard. This ensures a strong, leak-resistant connection, which is critical in high-pressure applications like braking systems in racing vehicles.
Why Choose obp Motorsport?
When it comes to braking accessories, obp Master Cylinders have earned their reputation as one of the most sought-after options on the market. Featuring an innovative internal double-seal setup, these master cylinders are prized for their unbeatable combination of reliability, affordability, and top-tier performance.
Whether you’re pushing the limits on the racetrack or working in demanding industrial environments, obp Master Cylinders are designed to deliver outstanding results wherever high-quality components are essential.
| Bore Size | Part Number | Piston Stroke | Max Flow |
| 0.625” | OBPMC01 | 34.3 mm | 6.78 ml |
| 0.700” | OBPMC02 | 34.3 mm | 8.51 ml |
| 0.750” | OBPMC03 | 34.3 mm | 9.77 ml |
| 0.875” | OBPMC005 | 34.7 mm | 13.44 ml |
| 1” | OBPMC007 | 34.7 mm | 17.57 ml |
| Height (cm) | 10.5 |
|---|---|
| Width (cm) | 5 |
| Depth (cm) | 21 |
| Bore Size | 0.625, 0.7, 0.75, 0.875, 1" |
| H.S. Code | 8708309190 |
UK Mainland Delivery Services and Prices
UK mainland delivery services and prices. Our delivery partner is Parcelforce
All orders received before 2pm will be despatched the same day via your requested delivery service. We will try to still despatch orders received after this time on the same day but this is not always logistically possible.
|
Delivery Type |
Cost |
Estimated Delivery Time (Excludes weekends and Bank Holidays) |
|
Standard Delivery |
from £2.65 |
2-3 working days from day of despatch |
|
Express Delivery |
from £5.25 |
Usually Next working day |
|
Special Delivery |
from £18.45 |
Next working day before noon |
Delivery outside the UK - For RRS product we are an authorised UK distributor and for this reason we can only deliver products with the UK
I cannot purchase liquids & pressurised goods - Certain liquids and pressurised goods are classed as hazardous when being transported outside of the UK via air freight. This unfortunately includes the Channel Islands, Northern Ireland and the ROI but they can be shipped on a non-Express service. For more information, please visit Parcelforce Prohibitions & Restrictions
Returns - We fully understand that circumstances can change and you might need to return an item. As long as the item is returned in its original packaging and condition along with your proof of purchase, we will be more than happy to exchange or refund it for you. We must receive the returned items within 28 days of the purchase date.
Returns Authorisation - Before you make a return, please email Returns to advise of the return, along with a reason for the return and any order details. We will then provide you with a secure returns number. We must receive your initial returns email within 14 days of receiving your order.
Packing and sending the items - Any items to be returned should be in their original packaging to help prevent any in transit damage. We must receive your returns within 14 days of you receiving your secure returns number.
Returns Address - The returns address will be issued with your returns authotisiation.
Receive your exchange, credit, or refund - When we have received your returned item we will exchange, credit or refund you as requested.
OBPMC01 OBPMC02 OBPMC03 OBPMC05 OBPMC07
