Brake cylinder resleeving is specialised work, requiring state of the art equipment and expert knowledge to ensure customer satisfaction first time every time. 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
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-- about 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