VelocityAP Manual, EGear + RTronic Audi R8 Lamborghini Gallardo Release Bearing Slave Cylinder Interchanges for 086141671 086141671M

With the age and condition of the vehicles we are now encountering issues with the hydraulic systems causing failures.  We are now hearing from customers who are purchasing from VAP who have seen OEM bearings fail within 2000 miles, which is indicative of underlying issues.  Please see below for additional guidance, and why we strongly recommend complete fluid replacement and inspection/testing of all the components of this system during installation.

Particulate contamination / metallic debris
A hydraulic release bearing/slave cylinder has a dynamic seal moving repeatedly across a precision bore or piston surface. Fine hard particles can get between that seal lip and its running surface and effectively turn the fluid into a lapping compound. Particle sizes particularly associated with hydraulic wear are in roughly the 4, 6 and 14 micron ranges. i.e. contamination far smaller than what you can readily see.  The pump element, valve block, actuator bores, damaged fittings/ports, or even debris introduced during previous work can all contribute.  Audi actually issued an R-Tronic TSB where damaged hydraulic sealing elements were traced to poorly deburred valve attachment ports in the hydraulic unit, so cleanliness matters enormously to seal longevity.

Wrong or chemically contaminated fluid.
Contamination with ATF, conventional power-steering oil, solvent, cleaning fluid, etc. can easily affect seal durability. Seal manufacturers emphasize that elastomer life depends heavily on chemical compatibility; incompatible media can cause swelling, softening, shrinkage, hardening or cracking.

Aged/oxidized CHF and water contamination.
We STRONGLY recommend replacing all the hydraulic fluid in the system at the time of installation.  Excessive temperature and fluid aging degrade hydraulic oil and can accelerate corrosion and component wear.  Free water is particularly undesirable and can be present once temperature solubility levels are breached (ie, when your original clutch/bearing overheated & failed.

Abnormal pressure spikes / pressure-control problems. The main system runs at about 40–50 bar, but pressure at the bearing is controlled downstream. A sticky clutch-control valve, contaminated valve spool, pressure-regulation issue or unusual transient can cause pressure fluctuations the seal is not designed to withstand.  This includes a weak or failing accumulator.