Worn out or coroded  brake and clutch cylinders can cause loss of braking efficiency, pedal vibrations and leaks. New cylinders cost a hefty amount. We can resleeve the master and wheel brake cylinders and clutch master and slave cylinders to make them just like new. Fly wheel and rotor disc machining services are also available.

 we can stainless steel sleeve almost any hydraulic cylinder as either a

  • bare body (no internals) for the person who prefers to be involved in the reconditioning process

Or

  • as an assembly (straight off the vehicle and ready to bolt back on when completed)

A stainless steel sleeving job is generally completed in 24 to 48 hours.

 

There are a few steps to the resleeving process, which are outlined below.

 

1. Cylinder Disassembly

 

The first step is the disassembly of the cylinder, which we have a special area for; including a trough that drains all the old brake fluid direct to the oil water waste separator. Cylinders are stamped with a job number to ensure tracking through the process and for future reference.

 

2. Ultrasonic Cleaning

 

 Cylinder bodies are bead blasted in either a dry or wet blaster, and internals are cleaned using our ultrasonic cleaning system, which is also excellent for alloy bodied cylinders and plastic reservoirs.

 

 3. Cylinder Boring

 

 Cylinders are bored in a precision jig using a 6 point adjustable cutter. Sleeves are predominantly press fitted which ensures the hydraulic sealant used is only a secondary precaution. Some brake remanufacturers use the ‘clearance fit’ method, which certainly is faster and easier, but experience has proven it not to be as reliable. We often see resleeving done by this method and in many cases the cylinders have piston to bore clearances in excess of critical factory tolerances, which causes leaks and short service life.

 

 4. Sleeve Preperation and Pressing

 

 Cylinders and sleeves are put through another cleaning process, and then are pressed in on our hydraulic press in one continuous stroke. Cylinders are cured for 30 minutes at 100°C

 

 5. Drilling and Honing

 

 Next the cylinder port holes are drilled. Compensating type master cylinders have the compensating hole drilled in them with a 0.7mm drill. Following drilling, cylinders are honed and all holes deburred. Honing is important firstly to ensure all holes are deburred so seals are not clipped and to give the bore a surface that will retain brake fluid for lubrication. Too fine a finish and the seals will have trouble sealing, and too coarse a finish the seals will wear prematurely.

 

 6. Sleeve Testing

 

 Some resleevers will say “we don’t have to test because ours never leak!” Great in theory, but in practice, some cylinders, such as alloy master cyls can leak because of porous casting. NBS test all cylinders at 2000psi, and yes, some do leak- 1 in 500, but this one reason why we test. If leaking does occur we have a specialized process developed to rectify this. We test our cylinders to guarantee you peace of mind, and offer an industry leading warranty.

 

 7. Quality checking

 

 Next a quality check is done to ensure all holes are drilled and surface finish is up to standard. Bore sizes are measured with a bore micrometer, and records kept as part of our commitment to quality, and ensuring factory specified tolerances are maintained. This meticulous record keeping has allowed us to build up a database of what does and doesn’t work across a wide variety of cylinder models. Our reconditioning workshop is designed for smooth flow from one process to the next, to offer fast turnaround on reconditioning.

 

 8. Cylinder Assembly

 

 The next step is the assembly if so required. As most would be aware, NBS carry a large range of brake rubber components. We run this program to ensure the quality of our rebuilding. Nothing could be more true than the saying “there’s rubber and there’s rubber.” We use OE quality components, not inferior imports. Pistons are measured for size and to ensure manufacturer’s tolerances are maintained. Finally cylinders are function tested on our purpose built jig to ensure correct operation.