It depends on the condition of the unions.I have had problems to unscrew the hose from the brake pipe union because it was to tightened previously with too much pressure.Add to this that on the left side the clearance is limited due to the gearbox (2.1td).But as a procedure it is fairly simple.You drain the hydraulic system and depressurise it,replace the hose than refill the hydralic system and pressurise it.
Spyrious, August 2008
