23-04-2018, 06:05 PM
(This post was last modified: 23-04-2018, 06:10 PM by carlukepeugeot.)
It works a bit differently to what it would appear looking at it I think. As far as I remember, what actually happens is that when you put your foot on the brake, the hydraulic 'pressure' drives the piston outwards, increasing the volume of the chamber and decreasing the remaining pressure available to act on the brakes. The lever attached to the piston presses against a big spring. It's a bit like a 3rd wheel cylinder in the circuit.
When the trailing arm rotates upward due to extra load at the rear of the car, the spring is compressed making it harder for the piston to come out - so it comes out less - thus the volume increase is less than in the unloaded condition and more of the pressure is retained to act on the brakes. It will always be in the 'closed' position when the brakes aren't being applied. If I remember correctly there is a small return spring to bring the lever / piston back in too so when you lift the car all that happens is that the big preload spring goes slack as the trailing arm drops.
Mine started leaking and I nursed it for a while until it was leaving puddles on the pavement. Was a ballache to replace, mainly because I ended up having to renew most of the brake lines due to the unions being rusty and seized. In the end I just bought myself a decent brake pipe flaring tool plus a roll of cunifer pipe and the fittings, dropped the axle down at the drivers side and set about it.
When the trailing arm rotates upward due to extra load at the rear of the car, the spring is compressed making it harder for the piston to come out - so it comes out less - thus the volume increase is less than in the unloaded condition and more of the pressure is retained to act on the brakes. It will always be in the 'closed' position when the brakes aren't being applied. If I remember correctly there is a small return spring to bring the lever / piston back in too so when you lift the car all that happens is that the big preload spring goes slack as the trailing arm drops.
Mine started leaking and I nursed it for a while until it was leaving puddles on the pavement. Was a ballache to replace, mainly because I ended up having to renew most of the brake lines due to the unions being rusty and seized. In the end I just bought myself a decent brake pipe flaring tool plus a roll of cunifer pipe and the fittings, dropped the axle down at the drivers side and set about it.