Nissan Navara D40 Yd 25ddti Brake Booster Leak

[Navara D40]

The Nissan Navara, start with a very low noise coming from brake pedal a little ssssssssss, so I start to listen carefully and there was an air leak, coming from the brake booster itself, so I need to replace all the part. And I experience a little losing off power on brakes.
Anyone knows if that air leak can cause loose power on hi RPM?????????

 

[Old.Tony]

There have been a couple of reports (over the last decade) of the vacuum diaphragm in the brake booster failing, but much more commonly it's a vacuum hose failure. The brake booster is directly connected to the vacuum control of the turbocharger, so a bad hose affects both the brake and the turbo and thus the engine power.

You could just try replacing all of the vacuum hoses. It's 3mm internal diameter and cost me (last time I did mine) $5 a metre at Supercheap Auto. I used a little less than 3m of it.

To test the brake booster - if replacing the hoses doesn't fix it - you need a vacuum pump with a gauge (most mechanics would have this, as would any brake specialist). But then you'd also have to investigate the coincidental loss of power - which could be a faulty Boost Control Solenoid, or a failing turbo, or a faulty actuator - try the hoses first and get back to us.

 

[Navara D40]

Great information,
That brake booster air leak can affect the turbo it self causing a turbo lack at high rpm?
History.
When i go hill climbing at hi altitude 2000m at 3000m the navara lose power at 3000rpm, it's like if 3000RPM be a threshold, but if the car pases 3100RPM it kicks all power but slow and reaches almost 5000RPM.

 

[Old.Tony]

Air pressure/temperature are all noted by the combination of MAFS and the boost sensor, so if the turbo is working correctly (no vac leaks, BCS is good, actuator is good) the engine response and power delivered at high altitude shouldn't be wildly different. There will be some variation, of course, but it shouldn't be too wildly out.

I assume that you're not in Australia - the highest road we have here is about 2200m at Kosciosko.

 

[Scuba Steve]

I have a D40 2008 with the same vacuum leak. It does not affect the running of the vehicle the only way to fix it is to replace the seals in the booster. If you apply slightly pressure to the brake pedal the noise goes away. I have research replacing the outer seal but you cant buy it individually. Replacing the brake booster with a reconditioned unit is the only option.

 

[Navara D40]

Air pressure/temperature are all noted by the combination of MAFS and the boost sensor, so if the turbo is working correctly (no vac leaks, BCS is good, actuator is good) the engine response and power delivered at high altitude shouldn't be wildly different. There will be some variation, of course, but it shouldn't be too wildly out. I assume that you're not in Australia - the highest road we have here is about 2200m at Kosciosko.

Air pressure/temperature are all noted by the combination of MAFS and the boost sensor, so if the turbo is working correctly (no vac leaks, BCS is good, actuator is good) the engine response and power delivered at high altitude shouldn't be wildly different. There will be some variation, of course, but it shouldn't be too wildly out.

I assume that you're not in Australia - the highest road we have here is about 2200m at Kosciosko.

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Hi, Mr Tony, I’m from Costa Rica and here you climb mountains constantly, I frequently ask for parts for Nissan cars in Australia, because here the Nissan dealer don’t have all parts and special orders take to much time to arrive, for Example they don’t sale the SCV valve as a individual part, they sale the Complete Diesel Fuel pump and it costs 2500 usd that’s crazy.
Talking about Booster Leak,
-I check all vacuum lines with vacuum tester and all lines are in good condition and in the correct place.
I-check main vacuum line from vacuum pump to brake booster and is good.

So I do test:

1- I go to a mountain to hill climbing at 2800m to reach 3100m, the test was disconnect the vacuum line from booster and sealed, so the booster don’t have vacuum, of course brake turns super heavy, and again RPM fluctuates between 2900-3000RPM and can’t pases that limit, I still full pedal to the floor, and in one second or two car overpass 3100RPM and kicks all power to almost 5000RPM reaching 90KPH, so with this TEST, I realize that the brake booster leak don’t interferes with that little loss of power.

2- I do same test with booster vacuum line connect as factory and car have same loss of power at same altitude.

I check brake booster and is damage and I will replace all the part because you can fill a big amount of vacuum loss and brake turns heavy sometimes. The tsss tssss tssss noise is getting louder inside the car.
I am thinking about the power loss or turbo lack can be the common rail return line, what do you think?, I order to Australia Denso SCV and Preasure Sensor Regulator and now from various issues, I discard some with those new parts.

 

[Old.Tony]

I'm not sure the tss tss tss sound will be coming from the SCV or the return line. The fuel going back to the tank isn't under huge pressure. Inspect the exhaust manifold for any signs of soot just in case you have a gasket that's not sealing perfectly. I had one let go on the turbo-exhaust manifold interface.

 

[Navara D40]

I'm not sure the tss tss tss sound will be coming from the SCV or the return line. The fuel going back to the tank isn't under huge pressure. Inspect the exhaust manifold for any signs of soot just in case you have a gasket that's not sealing perfectly. I had one let go on the turbo-exhaust manifold interface.

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Hi, the sound is coming from the Brake Booster, and the sound can be listen inside the cabin under dash panel under the steering wheel.
The SCV runs fine and good no leaks there.
Thanks