Hydraulic pressure slow to rise

KevMayer · Unread post by **KevMayer** » 01 Aug 2009, 15:55

My Activa is still very bouncy for the first minute or so after start up. I've had my rear electrovalve off again and extended the small spring a lot more than I did last time. I'm sure the small spring is responsible for pushing the plunger forward when the valve is energised which enables the block to change to soft mode.

I've also changed the rear height corrector.

However, the suspension still remains hard at the rear even though I know the electrovalve is energised and working. So, the only reason for the firm ride is that the hydraulic block isn't switching until the system pressure is greater than the pressure in the Hydractive sphere.

i.e. the electrovalve switches but it won't change to soft mode until the system pressure rises above the centre sphere pressure at which point the piston in the hydraulic block will change state.

I don't have any hydraulic leaks, so, why does my pressure rise so slowly?

Xaccers · Unread post by **Xaccers** » 01 Aug 2009, 16:22

I've got a similar thing with Juliet, the back is very hard until suddenly there's a clunk and it drops, and is then lovely and soft.
I wonder if it's the rear activa ram keeping things up.
I also think my pressure is down as if the engine is just idling the steering gets heavier.
Makes me wonder if the crank pulley is slipping, causing the aux belt not to go round as fast as it should so the hp isn't pumping as hard as it should.

Sid_the_Squid · Unread post by **Sid_the_Squid** » 01 Aug 2009, 22:20

Makes me wonder if the crank pulley is slipping

Think you'd hear an almighty squealing, mine sounded like a stuck pig before Jim and I* changed it.

*well mostly Jim

Unread post by **CitroJim** » 02 Aug 2009, 16:29

Yes, either a squeal from the pulley or from you as it makes a guest appearance in the drivers footwell

Seriously, those pulley can be dangerous.

Kev, I'd be inclined to go see Martin at Pleiades and have your pump and pressure regulator looked at. The regulator does fall out of calibration after a while and the pressure falls. Martin recalibrates them as part of his refurbish.

He did my V6 regulator the other week and the suspension is now so much better in all ways. Definitely worth doing as low pressure will seriously affect the electrovalve's ability to reliably switch into soft mode.

Activas do take a long time to get it up. Mine takes a good 45 seconds whereas my V6 takes maybe 10 seconds. Remember you have 10 spheres to blow up and two hungry rams. It is going to take a while.

red_dwarfers · Unread post by **red_dwarfers** » 02 Aug 2009, 17:06

How would an out of calibration pressure regulator effect the standard hydropneumatic setup?
Basically, would it be worth getting refurbished as precautionary maintenance on a certain high milage Xant?

Unread post by **CitroJim** » 02 Aug 2009, 17:15

It's only critical on a Hydractive car Kev, where a certain level of pressure in the main hydraulic circuit is needed to move the hard/soft shuttle valve in the hydractive block. It's rather critical apparantly and low pressure will fail to switch modes hydraulically even though the electrovalve is switching OK electrically and mechanically.

The usual reason to have a regulator overhauled is because it leaks at the end. That's why I had mine done and the pressure recalibration came as a nice billy-bonus

KevMayer · Unread post by **KevMayer** » 04 Aug 2009, 17:49

Thanks for the replies.

I've just posted another thread without reviewing this one first. It may be slight duplication

I certainly would benefit from -

"I'd be inclined to go see Martin at Pleiades and have your pump and pressure regulator looked at".