Brake calliper changes after '93? (rebuild question)

[goldtop]

Just putting together my calliper overhaul shopping list, and it seems there are (at least) two different types. Looking up the Amayama parts catalogues, I got a different part number for the overall rear calliper between '95 (my previous NSX) and '93 (my current NSX). Did the callipers change with the upgrade to bigger wheels? If they did, do we know whether the pistons/seals/etc also changed?

To add to the confusion, I am working on a different set of callipers (unknown age) and my car which is some miles away may have had a calliper change in the last, so some compatibility info would be helpful. :)

Also: Biggred tell me they cannot source NSX calliper pistons, so they have taken the NSX off of the online ordering system.

[sorepaws]

There are 2 sizes for information

43215-SLO-J01 is 48mm diameter
43215-SL0-003 is 43mm diameter

[goldtop]

Thanks Mike. I will dig deeper on those part numbers and check the piston size before ordering.

[Kaz-kzukNA1]

The caliper/bracket/disc size change plus the different piston diameter were introduced for 97+ model.

Therefore, from the hardware point of view, there is no difference between the 93 and the 95 brake system.
ABS was still the ancient classic design but moved onto 2nd gen in 91-92.


https://lh3.googleusercontent.com/pw/AM-JKLUOqlsAobWc07MhwOhjnOTi4ttsvLpi_y80tH2QGrT58rwd1 _ct7RTo657lGhOL0y9Bhwxg1PX5gboBvCPH3DFDFZabyOY9HSs-mIgbpwjr2Hrm6eQPw8x2y6HFf7Cnf9ynCND36TeTf_OlvrsbaJ CuQg=w1080-h608-no?authuser=0
If you are looking for the caiper service kit for the 91 - 96 REAR, just get 01473-SL0-020.
Comes with the grease and you will need 2 if doing both the R & L rear set.

This is what you will find in the bag.
Please note that the piston and the bleeder plug are not included.
You may want replacing the banjo bolt as well.
The photo shows the 2 set of the 01473- .


If you have access to the actual caliper body, just like Mike suggested, measuring the piston diameter will confirm the spec.

Also, just for the rear side, you can use the casting number to distinguish the different spec.

91-96 Rear: 14CLP-15V
97+ Rear: 18CLP-16V

Unfortunately, this method doesn't work for the front side.
Although the casting no. (16CL-15VN) is the same, one of the piston diameter is smaller on the 97+ Front compared to the 91-96 one.


The master cyl piston diameter stayed the same between pre/post 97 models.
With the significantly increased piston diameter at the rear on the 97+ model, the change in diameter ratio between the rear caliper piston and the master cyl would result in different pedal touch.

Also, the aim of the 97+ brake spec was to shift the brake balance significantly towards the rear.

Considering the pedal touch and the brake balance, Honda decided to make one of the front piston diameter smaller on the 97+ than the 91-96 spec.
The ABS setting (hardware/software) were modified at the same time but still using that squeaking ancient design.


The reason you found difference between the 93 and 95 spec brake service kit is because you looked it up through the JDM parts list.

There are multiple factors causing this.
The law in Japan, revision timing of the parts list and the so called parts list magic.

Until 95, all private vehicles in Japan were forced by law to overhaul and replace specified rubber parts within the brake caliper, master cyl, fuel hose, etc at the specified interval.

For the caliper and the master cyl, it was every two years and for the brake booster, it was every 4 years.
It didn't matter how many miles covered during the 2 years period as it was mandatory.

For this reason, the parts list had to list up every single rubber parts within the brake system, etc as a standalone parts.

Then, any private cars manufactured on or after 01/Jul/95 or any private cars manufactured before that but with the parts mentioned above replaced with the same ones used on the post Jul/95 spec, these rubber parts were still recommended to be replaced at regular interval but became no longer mandatory by law.

At similar timing, Honda revised the parts list and since then, many revisions were made.

Due to the timing of these changes and the way the parts list was written, depending on the revision no, you would see the brake caliper overhaul kit for 91 - 96 caliper would only be applicable for the 95 and 96 models if looked at the [ Brake ] section of the parts list.

This was correct from a certain point of view because 95 was the first time when this kit became available.

However, it can be used for all 91 - 96 models so Honda did add additional pages in the parts list as [ Brake service kit ] section but placed it at the very end of the parts list.
They didn't change the diagram or the application info within the [ Brake ] section.

Thus, two different year model application information for the same parts no at two different pages within the same parts list.


Kaz

[goldtop]

Wow Kaz. Once again, thanks for sharing such deep and detailed info. I'll measure the pistons on Monday.

I think it's most likely that the callipers that I have are from before '97. The fronts are stripped (and with no pistons) and the rears are complete, but the pistons' surface looks beyond rescue (I've not yet removed them). Banjo bolts seem OK and cleaned up well. In fact, some of the rubber parts seem fine (e.g. slide pin boots), but I suppose are not worth reusing. So I think I'll order the full refurb set.

The email from BiggRed implied that it was only the pistons that they cannot source, so I'll see if Amayama has them.

[goldtop]

I was mistaken. I had assumed the front pistons would look just like the rears; that 'cross' pattern surface making contact with the pads. But instead, the front pistons are hollow. I thought the pistons were missing when I first glanced into the box. I now see they are present - one is 36mm and the other 40mm.

The sliding surface of the pistons has cleaned up pretty well, but there is some surface damage within the groove rings. Not sure if that's just baked-on debris that can be carefully removed with more effort, or rust. So I guess I'll source new pistons anyway.

[NSXGB]

Front pistons you can get from Rock Auto for sensible money.

[goldtop]

Thanks - will check them out. :)