juddery brake pedal from 10mph to stop!

[mikeyrockster]

Hi I have a 91 import nsx. Recently Ive been experiencing pedal judder when i brake down past 10 mph. The judder goes if the ALB light is on but this rarely happens. The TCS light came on once too. If the light does come on I just turn off engine and restart and it goes out but judder returns.
Ive bled all 4 calipers today to remove any air in system but didnt clear the problem. The ALB light stayed out.
Is it possible I have dirty sensors? I took the car for a european road trip in the summer and possibly boiled the fluid on stelvios pass on italian/swiss border so wandered if that may have caused a problem?

thanks, Mike

[Kaz-kzukNA1]

Hi, Mike.

Based on your other posts, it seems that you owned your NSX for over 2 years so I believe you are aware of the ‘kick back’ at the brake pedal when ABS/ALB was activated.
I believe you are not referring this ‘kick back’ as the same thing as the word ‘judder’ in your post.

Having said this, you mentioned that your ‘judder’ went away when the ABS/ALB Warning light (Yellow) stayed ON. When this warning light is ON, the ABS/ALB is disabled so you won’t get the ‘kick back’ from ABS at the brake pedal.

Are you experiencing this ‘judder’ almost every time when you are applying the brake pressure on deceleration and after hitting below 10mph point with no ABS/ALB warning light?
Or, is it occasional?

For 91 model, the brake fluid at the brake master cylinder/reservoir is completely separated from the one at the ABS/ALB reservoir. Therefore, bleeding the brake fluid at the four callipers won’t help much if your ABS/ALB was causing this ‘judder’.

You need to find out whether the issue is caused by the mechanical (dragged brake, damaged gear pulse teeth, tyre, air in the ABS/ALB system, etc) or electrical (wheel speed sensor, ABS/ALB computer, etc) failure.

First step is to read the failure code stored in the ABS/ALB and TCS computer.
Hope you have the on-line workshop manual so that you can understand the procedure on how to read the code….

Regards,
Kaz