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Today at Atelier Kaz - Private NSX Enthusiast, ex-Honda R&D engineer with F1, Indy/CART background

Eng Refresh, Health Check, etc 37

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Didn't like the level of corrosion at the brake banjo bolt so replaced both RR & RL ones.
Bleeder screws were fine at all four corners so just re-used them.

As we are not replacing the Brake master cyl, very important to use the pressure bleeding method.
Otherwise, you could destroy the old master cyl if you use the old text book method of pressing on the brake pedal.

Due to the effect of the white balance of the digital photo, not easy to show how dirty the air filter was.
It was almost like black. New OEM green one to be installed.

As reported earlier, disconnected the suspicious fuse from the wires hidden under the side sill pad.

New clip at the rear upper trim athough the fixing point was already damaged so I have a feeling that it will come off again.......

Compression check after the Eng Refresh.

Interestingly, the data from all three cyl at the rear bank were almost exactly the same as the ones measured before the start of the service.
However, the front cyl were dramatically improved by carrying out the Eng Refresh.
Normally, it's the rear bank that people tends to make mistake due to limited space.

Very happy with the result but already expected it when I fired up the engine with the rhythmical sound.
The owner will receive the full data through email later.

The missing spacer under the IG coil cover. Without this, the water can enter behind the IG coil cover.

New Rear IG coil cover and applied silicone grease to the gasket on both covers.

Adjusted the base idle rpm and checked the IG timing as well.
If your engine is properly adjusted and tuned, it should be able to idle even at about 600rpm. If it stalls, you have some sort of problem.

Already knew someone touched the idle air bypass screw as there was no locking paint.
Sealed it with the liquid gasket.

Updated 21-02-2015 at 08:23 PM by Kaz-kzukNA1

TB/WP/Valve Service


  1. hazman's Avatar
    Great job/write up as usual, Kaz. Out of interest, why could the master cyl. be destroyed by using the normal bleeding method - is the issue specific to the NSX? I ask because I'm about to carry out the process on my other car!
  2. greenberet's Avatar
    I think it's because when you brake, you don't push the pedal to the floor, as you do with the clutch. You push the brake master cylinder in only a certain percentage of the way. Behind that point, dirt builds up. If you push the pedal all the way to the floor when bleeding the brakes, you'll push the rubber seal over that dirt and there's a good chance you'll damage the seal in the process.
  3. Kaz-kzukNA1's Avatar
    Itís not NSX specific and depends on the age and design of the master cyl on any cars.
    In Japan, we used to be forced to overhaul the brake master cyl every two years by law so it was common to re-use the cyl bore/body and just replaced the piston /seal/cup. Thus, well known fact within Japanese automotive industry.
    As greenberet mentioned, over many years, the piston/seal/cup inside the master cyl would travel almost exactly the same distance and eventually, the cyl bore would worn out with stepped finish at the very end of the travel. The black residue at the bottom of the master cyl filter is the trace of worn rubber as well as the aluminium dust from the cyl bore.
    So, during the brake bleeding process, if you floor the pedal to let the piston/seal/cup assy to travel through this stepped worn edge, you are very likely to damage the lip of the cup or even let the cup to be reversed and as a result, the brake pedal will feel almost no resistance or very weak feeling.
    Also, there are certain cars that donít like vacuum bleeding.