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Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 22905
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Jaguar XF diesel 2011. When I come to start my car first thing

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Jaguar XF diesel 2011. When I come to start my car first thing in the morning the brake pedal is very hard and and I have to exert some pressure to actuate the micro switch which connects the starting circuit. Subsequent restarts that day are fine and there has been no deterioration in braking performance that I've notice. I don't pump the pedal after switching off or before starting. Is this a problem with the servo vacuum seals? Should I be concerned?
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Customer: replied 2 years ago.
I'm still needing a reply, Shantal
Hello I'd say that this sounds like the vacuum pump may have a leakas being a deisel there's a pump driven off the end of the cylinder head and looks like this there will be a rubber hose that runs from this pump to the brake servo so check along this pipe for any signs of leaks , crack and tighten any clips that are present
Customer: replied 2 years ago.
Yes that's an interesting possibility, Matt. Obviously vacuum is leaking overnight from somewhere (i.e. air is getting in). Is a vacuum normally retained in this pipe after the engine is turned off and the pump stops? I'll look at the pipe but it's dark and cold at the moment - I'll look tomorrow! Thanks
Hello there should be a 1 way valve in the pipe to hold some vacuum in the brake servo so it works form the 1st push
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Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 22905
Experience: BEng hons Mech engineering, in auto industry 22 years
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Customer: replied 2 years ago.
Don't worry I always intended to reply. There was no visual damage to the vacuum pipe. Anything more than that I wouldn't have attempted myself so I took it yesterday to a jaguar specialist. They started it cold and road tested it and tell me there's nothing wrong with it. So, there you are! I'm worrying unnecessarily
glad to hear it