2.0hdi brake servo problem

[Rowland]

Hi, 

I'm new to the Berlingo and the forum.

Have owned a 2002 Berlingo 2.0 Hdi for a few months which came with no history.  Last weekend the brakes semi-failed in a strange way.   With the engine running the brakes feel fine for the first couple of presses then the pedal goes hard as it would if the engine is off.  After a while it recovers and I get a couple more presses with assistance before it goes solid again.

Maybe related, the exhaust makes weird noises, like there is a leak but this seems to go away when accelerating.  There isn't any turbo boost as far as I can tell.  

Thanks in advance.

[Sol]

Check the vacuum pump, and any vac hoses such as the main one to the brake servo drum. You have a vacuum leak somewhere of course.

Diesels have no vacuum at the intake since they have no throttle butterfly like a petrol, and need a working vacuum pump and a reservoir to hold that vacuum. Find that, and check all hoses coming from it. This is also how the turbo boost is controlled. They will all be related.

Splits on hoses tend to be near clamps or clips, and underneath where oil can collect when dripped or sprayed, also engine heat affects the bottom of hoses more than the top (since heat rises up from below) so look at these areas.

Service history is irrelevant for a fault, because faults stem from failed components and the failed items are not always "service items" which are checked during the service procedures.

[Rowland]

Check the vacuum pump, and any vac hoses such as the main one to the brake servo drum. You have a vacuum leak somewhere of course.

Diesels have no vacuum at the intake since they have no throttle butterfly like a petrol, and need a working vacuum pump and a reservoir to hold that vacuum. Find that, and check all hoses coming from it. This is also how the turbo boost is controlled. They will all be related.

Splits on hoses tend to be near clamps or clips, and underneath where oil can collect when dripped or sprayed, also engine heat affects the bottom of hoses more than the top (since heat rises up from below) so look at these areas.

Service history is irrelevant for a fault, because faults stem from failed components and the failed items are not always "service items" which are checked during the service procedures.

Thanks for the reply.   Is the vacuum pump driven by the alternator belt or from a shaft?   Also, could this be why there doesn't seem to be any boost?

[Sol]

It's driven off the cam with a dog drive end, there are seal kits on eBay for them too. Yes that could be why you have no boost - but are you certain there's no boost? You cannot hear the turbo spooling on most of these. It has a baffle / resonator on the outlet.

[Rowland]

It's driven off the cam with a dog drive end, there are seal kits on eBay for them too. Yes that could be why you have no boost - but are you certain there's no boost? You cannot hear the turbo spooling on most of these. It has a baffle / resonator on the outlet.

Interesting - there’s no lag and it’s really slow so I assumed no boost.   The noise it a bit crazy, it’s like a blown exhaust that modulated by load so sometimes it’s quiet.

[Sol]

Is it a 1.9d or a 1.6 HDi? The 1.9 has no turbo at all and is deathly slow but reliable.

If you have crazy noises coming from the exhaust, then you have problems and may be better to seek the help of a garage who know what they are doing.

[Sol]

A mi me pasa lo mismo en el escape, ayuda por fa

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