Danoland solenoid flush, still getting clicking from abs.

[SoloNSX]

Tried out the Danoland solenoid flush diy. The solenoids on my abs have been clicking randomly for a while now. Usually on cold start up when I get going, then it'd go away. Then it would make the clicking noise at autox events since I'm working the abs system a lot. It would always stop after a little bit.

Followed the instructions to a T. No problems, everything seemed to go as intended per instructions. Went out to test the abs. Still getting some clicking noises from the abs system. Never an abs light.

Should I redo the whole process again? I noticed when i opened/closed solenoid switch rapidly, it would make some sound like it was opening/closing something then after a few times it stopped making noise, that's when I stopped, cleaned out the fluid, put new fluid and then opened the motor switch for about 20 seconds. I'm assuming this is normal?

The abs works. It locks up for the first fraction of a second then pulses. About 80-90% of autox runs, the solenoids will make the clicking sound either mid run or by the end of the run. For regular street driving, they almost never make any noise.

Any input would be helpful. Thanks!

 

[asylum]

Everything seems fine. The clicking sound you hear is the pump. It is normal that it runs 5 to 10 seconds, let say, every 3 to 10 times you activate the ALB or when you start the car.

 

[Kaz-kzukNA1]

From what you wrote, it’s the sound of ABS pump and not the solenoid. Welcome to the Classic ABS club with that screeching sound of ABS Pump.

From the photo, your ABS is the Classic but 2nd generation so better protection against the leaky solenoid issue although it will happen if not exercised regularly (you are autoXing and activating ABS regularly so very likely to be fine).
Also, your NSX is DBW so 95+ model.

The classic ABS is a high pressure standby system.
The high pressure fluid is stored in the accumulator and when it’s required, it will transfer the high pressure fluid through the inlet/outlet solenoids to prevent the wheel from locking (pulsates the brake pedal) or maintain the brake pressure.
The accumulator is the sphere shape parts at the bottom of the system and it consists of rubber bladder with high pressure nitrogen gas as the back pressure.

When the ABS pump is activated, it transfers the fluid from the reservoir to the accumulator and by compressing the nitrogen gas behind the bladder, it will create super-high pressure fluid storage.
There is a pressure switch at the accumulator and as soon as the pressure drops the specified threshold, the ABS computer will trigger the ABS pump to re-charge the accumulator if the RR or RL wheel speed sensor shows more than 10kph (or about 8mph). This is the reason why you hear the ABS pump noise not immediately after starting the engine but only when you just started moving/driving your NSX.

Also, as you experienced during the autoXing session, you will hear the ABS pump noise if you have activate the ABS several times after the last time you triggered the ABS pump.

When the system is new, the ABS pump is very quiet, the accumulator can store much higher pressure and the solenoids won’t leak that you won’t hear the ABS pump being triggered for months even you haven’t activated the ABS for quite some time.
Simply because there is enough high pressure fluid stored in the accumulator before it hits the pressure threshold next time.

Over the years, the nitrogen gas can penetrate through the rubber bladder very slowly or the bladder itself can fail and thus, the actual fluid pressure inside the accumulator is much lower compared to when the system was new and it’s much closer to the threshold pressure.
Hence, you are more likely to trigger the ABS pump frequently after activating the ABS.

Also, if you have leaky solenoid issue, the high pressure fluid is slowly but gradually leaking from the accumulator even while your NSX is parked so next time when you start moving your NSX, it will trigger the ABS pump.

So, if you are triggering the ABS pump more frequently than before, you have either lost some of the nitrogen gas from the accumulator or you have leaky solenoid issue.

By the way, if you open the ABS pump and the motor, you will see eccentric bearing with plunger and gear mechanism at the motor shaft. That screeching noise is the result of broken down grease and wear at the gear mechanism.
Again, when it’s new, it’s very quiet but depending on how many times you triggered the ABS pump, the noise gets louder and louder over the years.

So, in summary, from the point of new system, it’s not normal to hear that awful noise but it’s quite normal for the aged tired ABS pump to make that noise.
However, you seemed to be triggering the ABS pump more frequently so there is a chance that you lost some of the nitrogen gas from the accumulator but not enough to trigger the ABS light.
It will trigger if the pump operated for more than 2min due to not being able to achieve the pressure threshold.
This is when the ABS T-wrench becomes handy as you can measure how much fluid stored in the accumulator to determine whether you lost too much nitrogen gas or not.

Using the danoland method is fairly effective if you have leaky solenoid issue but seems like your all 4 solenoids to be healthy and this method can only flush part of the ABS and not the entire system.
Also, you need extra step if you have stuck closed solenoid issue.

Obviously, it won’t fix your tired ABS pump noise….

Kaz