Howdy to all,
Hope someone with expert (Brake System) knowledge can help me to resolve this issue?

I read many threads that discuss potential for vacuum leaks in hose connections from Engine Intake Manifold to Brake Booster Unit.
Some threads show photos of an inline 'Check Valve' fitted between Intake Manifold and Brake Booster.
PLEASE NOTE: My X-Type DOES NOT have a check valve in place.

My Query are;
1. Should there be one installed ?
2. What is the function of the Check Valve ?
3. What is the consequence of not having a Check Valve installed ?
4. Does absence of a Check Valve - effect Brake Booster performance ?

Could it be that someone in the past has simply fitted a continuous hose (without Valve) to eliminate a failed or leaking valve ?

If a Check Valve should be there.... can someone please advise if it is something special (peculiar to X-Type) or where I can get one from.... ?


Thanks to all for reading....

 

LCGI, your car should have one. The purpose of the check valve is to maintain the maximum vacuum possible (as I understand it) at the brake booster so you have maximum brake effort with minimal foot pressure. Now, with this being said, a lot of cars don't have this check valve and they function just fine. The idea is that when you go to wide open throttle (in the case of your throttle failing), the manifold vacuum drops to a very low value and therefore decreases the amount of aid that the brake booster provides. Is this a big issue? Depends on if you have a strong leg or not. The one video I saw of a "runaway" motor where they were measuring the amount of foot pressure on the brake pedal needed to overcome the engine (they were using a Ford Taurus as I recall) was 175 pounds (think of trying to go from a squat position to standing upright using only 1 leg). This would be needed to be applied with a single foot. Without the check valve, you may be looking at requiring more force than that.

So, is this an issue? For a short period of time I would say no as the likelihood of having a failure like this is unlikely. But, as time goes on, it can be.

As for getting the correct part, your local Jag dealership will have it. The hose is like $15 as I recall. Worst case, you have JPLV which will ship it to you, there is Jaguarparts.com that will ship it to you, or you have Hennessey Jaguar (of Atlanta, GA, sponsor here) which will ship it to you. All 3 of these places have good prices on the parts.

 

Hi Chris,
Thank you for your comments and wisdom.

I will get the Check Valve and then simply cut and then insert the valve into the existing hose.

I assume this Check Valve has a simple 'non-return' function - therefore the direction of flow is critical to proper installation.... can you confirm the correct direction of Flow..? (TO or FROM - the Brake Booster Servo)

Cheers

 

I was able find and download the attached PDF... explaining the function of the Brake Booster and the Check Valve.

Thought others here may find this useful reading and reference too.

 

LCGI, you want the high pressure side of the check valve to be facing the brake booster. That way, any time the brake booster is at less of a vacuum than the intake manifold, it will bring the brake booster to the intake manifold vacuum. If I need to explain it a different way, just say so.

 

Chris,
Clear as mud is that explanation )

As I understand it, flow through the Check Valve can only occur in one direction and that flow direction must be away from the booster - so that a vacuum can be established and maintained inside the Booster. (provided by Engine Intake suction)

Another interesting point here, I have just read that some Boosters have built-in Check Valves and I am wondering if the Brake Booster on my Vehicle is the original Factory fitted unit? For instance, if the current Booster is a replacement unit (say with integrated Check Valve) then there would be no need for the mentioned IN LINE Check Valve hence as to why it is not there ?

I have attached some photos of the existing unit to see if anyone recognises it as being an Original Factory Unit or otherwise !

I can tell you the label on the Booster has the following info;

BOSCH 0204024044

Product 20-06-03
of France

1X43-2B195-BF

I suspect it is the Original Brake Booster. That being the case, then I would appear to require (the missing) Check Valve.

Cheers,

 

LCGI, you have the right idea. Flow is away from the booster. Once you get the correct part, how you put it in will be very obvious.

From the looks of things, someone put in the wrong line between the booster and the intake. Get the new one and all will be good.

 

UPDATE:
Have been in touch with Jaguar Australia - via my Local Dealer.

They have told him that what we thought was an inline Check-valve is NOT a Valve at all,
but is a simple Rubber Grommet - to prevent Vacuum Line contacting with surrounding surfaces.

Therefore, the Dealer has confirmed that (by looking at my photos) the installation was correct.

This then tells me that the non-return or check-valve must be located inside the 90º elbow that fits directly into the Brake Booster.
Incidentally, the Dealers RRP for replacement Vacuum Line is AUD$134.00

Dunno Chris, maybe the check-valve configuration and its position is peculiar to US models?

Anyway, tomorrow I will remove the existing vacuum line and its connector to the Booster
and do a simple flow-test through it. If air pressure only goes one way - I will have my answer and solution.

Will keep you posted....

 

I don't know ...

Please see TSB XT206-05 for reference on check valve ...
JagRepair.com - Jaguar Repair Information Resource

 

Hi David,
The plot thickens mate..... but I thank you for your interest and information.

I have forwarded your TSB Reference to my Local Dealer and asked that he talk to
Jaguar Australia again.
However, the photo of the Intake Manifold shown in the TSB is not the same as on my Model (see photos)
Could it be the Check-valve mentioned in TSB XT206-05 is related to 2002 (and earlier) Models only ?

I will keep this thread posted with any further information received.

 

UPDATE:
My local Dealer has now finally found the correct Part; C2S17552

It seems all the previous confusion - stems from Jaguar Australia who are in the process of consolidating their resources.
ergo;
• Parts Warehouse - is now located in Melbourne.
• Parts Office - still remains in Sydney.

Go figure that - eh.... ??

Anyways, attached is image showing what part: C2S17552 - looks like.

RRP mentioned is; $AUD 116.00 (incl. 10% GST) + freight.

Cheers,

 

Hi. i have quik question, 2003 jaguar xtyp 2.5. im try Replacement Brake Booster Vacuum Hose Check Valve Tube. Booster side its easy, but how is comeout, take out intake side ??? Thanks...

 

You should be able to press down on the ring around the tube and gently pull it straight out. The ring and the sealing O-Ring stay in the manifold

 

Ok. Thank you let me try. U let you know.

 

I wish I had seen that picture at the beginning. Obviously someone tried to fix a vacuum leak with silicone. Scrape all of the silicone off. Hopefully you will still see the black ring. If so push down and extract the hose. I it isn't there then use what ever force necessary to remove the hose.
If the ring is still there then you will need to change out the O-Ring inside the black plastic ring. If the ring isn't there you will need a new a new vacuum hose connector kit. SNG Barratt if you go to there web site and do a parts search you will see what the connector kit looks like.
The brass ferrule will still be in the manifold. You can remove the plastic ferrule and O-Ring from the kit and install it into the brass existing ferrule.