NSX Health Check Service

[Kaz-kzukNA1]

1. Brake Calliper
Until several years ago, in Japan, we had to carry out the calliper overhaul (OH) every 2 – 3 years by law.
Since the rubber material has improved a lot, we are no longer forced to replace the boots, seals, cups and etc under the new law. However, it is still recommended by many reputable garages in Japan to have the calliper OH every 2 years in order to inspect the inside of the callipers and to prevent the rust from getting inside.

It seems that for UK NSX, the calliper OH is not carried out on a regular basis. In fact, I noticed that this is not just the case for our NSX but also for many other cars on the road.

I was lucky enough to drive many NSX based in UK and none of them were showing the same level of stopping power or the solid pedal feeling of the original spec.

One of the reason for this seems to be that the owner believes or being told that the OH is not required if the car was not driven regularly or if it is at low mileage.

Especially, among the owners with super low mileage NSX, the calliper has never been touched for nearly/over 10years.

This is very worrying as the piston(s) inside the calliper just sits at the same position for many months/years if the brake pedal or side brake were left without any movements. Unless your NSX is kept inside the 24Hr air-conditioned garage, the moisture in the air will eventually get into the calliper causing the rust slowly. It will damage your piston, cause seizing and in the worst case scenario, it will cause brake fluid leakage or entire calliper to be replaced.

Therefore, regardless of your annual mileage, it is essential to have your callipers serviced at regular interval. Needless to say, the brake fluid should be replaced every year for standard NSX regardless of the annual mileage and for those who take out their NSX on track, well, I don’t need to say anything as they are more experienced than me. For those who are interested, they are replacing after every track event or after a few events depending on the brake fluid used.

Recently, I was working on one of the member’s NSX. Prior to this, the owner took my NSX Health check service and I drove this particular car. Straight away, I didn’t like the feeling of the brake.

It is a low mileage, well looked after and being serviced regularly at the reputable garage so I thought it just needs good bleeding and going to be an easy job. Wrong….

The Front calliper before the service. As you can see, it is very clean and even I was not expecting to see the problem inside…

Most of the pistons showed rust under the lip of dust boot but one of them was particularly bad and didn’t move smoothly. It had rust even at the seal area and thus, enough damage was done and had to be replaced.


This is quite common for NSX not driven regularly and if the calliper was not overhauled on a regular basis.
There are lots of know-how that are not on the workshop manual to minimise these rust getting inside the calliper and these can only be done at the time of overhaul. Therefore, regular service on the calliper is a ‘must’ item.

So, the Front calliper was inspected in detail and serviced using the overhaul kit with additional parts based on the past experience. The bleeder plug and cap were also replaced with the new ones.

[Kaz-kzukNA1]

The Rear calliper requires extra work as it has hand brake mechanism inside and in the piston as well.
Quite often, if the car was not used regularly or the hand brake cable was not removed for a while, the pin which secures the cable to the calliper will be severely rusted and thus, you’ll struggle to remove it.


And then, one of the piston didn’t rotate smoothly even using the special tool….
Finally, managed to disassemble the calliper and started the overhaul process.

Using special tools to service the hand brake mechanism.


Hand brake lever and parts used for overhaul.


Now the piston rotates very smoothly and we have a happy calliper.

[NSXGB]

Kaz,
Which are the special tools required to service the handbrake mechanism?

Do the offending parts just require a clean and re-grease?

[Kaz-kzukNA1]

Hi, NSXGB.

Although Honda states it as 'special tool', you can probably use deep socket to hold the adjuster down against the force of spring.

I just use the Honda special tools because I got them at special price while I was in Japan. Also, I don't want to scratch the internal bore of calliper housing.

You must obtain the long bent nose snap ring plier but you may already have something suitable if you work on your car. WIthout it, you'll spend long time to remove just one snap ring (5sec job) as straight type plier won't reach it or your plier will be hitting the folk of the calliper making it difficult to catch the snap ring. Time is precious for my service as I can only work on the NSX during the afternoon of my private time.

Any rubber parts have to be replaced with the new ones if you have disassembled the calliper.

There are two tiny rubber parts inside the handbrake adjuster so remember to replace them addition to the normal boots and seals.
If you use any chemical for inspection/cleaning rather than the brake fluid, the rubber parts will expand so you must replace them even if you didn't disassemble the handbrake mechanism.

This is why the workshop manual states to use only the brake fluid for the cleaning purpose.

The pistons can be re-used depending on the position of the rust/damage. You will learn it from the experience but if you see any damage to the piston wall below the dust boot groove, it's best to replace it as you don't want to take any gamble.


Regards,
Kaz