I have an old land cruiser (1990). Son borrowed it recently to shift furniture in Bristol. Having completed the task he set off to return the vehicle. Downhill, approaching a T junction, he pressed the brakes to stop at red lights. Nothing. Total brake failure. Fortunately he sailed across the junction and up a bank on the opposite side where he came to a halt with the handbrake. No damage to driver or vehicle V fortunately. Vehicle was MOT'd about a month ago. RAC recovered the vehicle to home. Found ns rear brake cylinder shot. Replaced duff cylinder and brake shoes both sides (plus hand brake cables which showed signs of wear).
Why should the brakes have totally failed when one wheel cylinder failed in a split circuit system? Is this indicating that the master cylinder also needs replacing?
Having replaced cylinder/shoes etc I came to bleeding the system. All seemed to be fine when completed. On driving the vehicle the brake warning light on the dash 'occasionally' comes on. More worrying is that if I press the brake pedal with the engine running at tickover it very slowly sinks to the floor. This doesn't seem to happen with the engine switched off. Am I right in thinking that the master cylinder has failed and should be replaced? If so, why was there no prior warning, ie. light on the dashboard.
Thanks in advance