has anyone ever overhauled the valve block on an l322 ,had mine in the dealers today as suspension is locked at normal ride height,computer says reservoir pressure not increasing when filling, however compressor is fine have removed the relief valve in the boot and now the problems down to the valve block or pressure sensor ,got a new sensor coming tomorrow so if this doesn't work will have to overhaul the valve block some how ,just wondered if anyone has had one out and messed about with it.