NC Front Brake Calliper Rebuild Information

Charlie Brown · Postby **Charlie Brown** » Fri Aug 22, 2014 10:20 am

I’ve just completed rebuilding my front right brake calliper and thought I’d share my experiences for those thinking or needing to do the job.

First up, why the rebuild?

I found that the brake pads weren’t releasing fully from the rotors. I could hear them rubbing when driving slowly. Slider pins were regularly cleaned and greased so that wasn’t the problem so I investigated possible causes and found one of the main reasons was hardening of the calliper piston seals.

I order two seals kits containing the piston seal, dust boot, two slider pin boots and silicon grease sachet from MX5Parts in the UK at a cost of $47 and they arrived a week later.

I view Blue Meany’s (from miata.net) You Tube video found here, https://www.youtube.com/watch?v=QXcClOfFmlg to see how it was done.

One problem is that he uses compressed air to push the piston from the housing, something I don’t have at home. After a bit of lateral thinking I came up with the idea to use the car’s air pump to do the same thing as the compressed air to push the piston out.

Next problem, how to get a decent seal between the air hose and the inlet into the calliper. This was solved by using cutting the end from my old rubber brake hoses at the fitting (the car has braided SS hoses now), attaching it to the calliper and holding the air hose hard up against the fitting. 15psi was all that was needed to pop the piston.

Then the rest was as per Adam’s video with the exception that I used the silicon grease rather than brake fluid to ensure everything slid easily into place. I didn't rush the job (the grease up seals are slippery little buggers) so this first up change took about 2 hours from jack up to jack down.

As for the old seals. The dust boot was very hard and distorted which explains why the piston didn’t slide back and the binding occurred.

So one down and one to go then maybe I’ll change the rears as well at a later date.