Thinking about renewing these as they're still the originals as part of preventative maintenance when my car goes in to Jimmer's for the clutch and flywheel upgrade. I have heard they occasionally fail? I believe when they fail, they can make the system wheeze a little when off-throttling. Has anyone else experienced this?

 

 

Oh that's what it was. I deleted it, should i put it back? What does it do?

 

I just thought it was a straight joiner so was neater without it.

They're check valves so imagine a ball bearing and a spring although I've never had one apart.

I'd be inclined to refit them. Check valves are also known as non-return valve, so you could be pressurising your vacuum system at the wrong point without them although I don't fully know how detrimental it would be without them. If you refit, make sure they go on the correct way round!

I'd be inclined to refit them. Check valves are also known as non-return valve, so you could be pressurising your vacuum system at the wrong point without them although I don't fully know how detrimental it would be without them. If you refit, make sure they go on the correct way round!

A quick google I think you're correct, the one way valve prevents air being sucked into of the booster. I'll refit before I cause damage :)

Good job I posted this!

Good job I posted this!

Haha, yes would have lost brake power when gone into boost!

I robbed mine off a newer Nissan at the car graveyard.

I robbed mine off a newer Nissan at the car graveyard.

 

Had yours gone bad?

No I needed an additional one for the manual conversion. Came of a primera I think.

The check valve maintains a vacuum within the servo should the vacuum provided by the engine (or vacuum pump) fail allowing some servo assistance until the vacuum depletes.

 

It also stops the servo being put under positive pressure (boost) from the inlet manifold.

 

No harm in replacing it with a new one. Probably the same valve fitted to other cars if its NLA for a Z.

The check valve maintains a vacuum within the servo should the vacuum provided by the engine (or vacuum pump) fail allowing some servo assistance until the vacuum depletes.

 

It also stops the servo being put under positive pressure (boost) from the inlet manifold.

 

No harm in replacing it with a new one. Probably the same valve fitted to other cars if its NLA for a Z.

Also remember when your on throttle (NA engine or FI) your vacuum wont be there to give assistance when you first brake after letting off the throttle so the valve again helps maintain that vacuum until the manifold vacuum increases after the throttle body is closed.