noz
October 12, 2011 08:08 am
Hi Brian,
The problem with the hydractive sphere and the brake accumulator (assuming you have either or both in an S1) is that they trap pressure behind their respective valves. The way to depressurise the system is to pressurise it first and this opens the said valves, hence my previous suggestion and your initial question. The system can then be depressurised in sequence and safely.
If your model has a hydractive sphere on each axle then you can unscrew the tubing nut on the large 10mm dia pipes going to the wheel spheres. They are of the conventional flared end type whereby slackening them off will allow any pressurised fluid to safely escape past the threads. You'll just need a bucket underneath.
To depressurise the brake accumulator (again assuming it has one), open the bleed nipple on a brake caliper and press the brake pedal. This will allow the contents of the sphere to empty safely through the bleed nipple.
Trying to de-pressurise by slackening off one of the traditional Citroen pipe ends is not a good idea. In that tubing arrangement the threads of the tubing nut take no part in the sealing process. The rubber ferrule on the end of the pipe does all of the sealing. Hence, even when you slacken the tubing nut nothing will escape. That is, until you reach the last thread. Once the tubing nut threads clear the last thread on the fitting the pressure then pushes the entire pipe out of the fitting with an immediate and explosive release of pressure with obvious consequences. However, if the car is scrap anyway, you can afford to cut the pipes with a pair of snips. Cover the point at which you are going to cut the pipe with a rag and cut the pipe with the snips underneath the rag. As you press on the snips handles you'll crush the pipe somewhat in the process. This will limit the hole out of which the pressure can escape. The presence of the rag will eliminate the velocity of the resulting jet of fluid and safely allow the pressure to escape.
Hope that clears up any confusion.
cheers
noz