If your memory is good, you may recall that way back in December of 2017, I filed a blog post entitled “Winter Storage, and the Start of the Miata’s Next To-Do List”. Somewhere in there, I wrote words to the effect that “should we have a mild winter, I’ll be attending to some maintenance, repair, and detail items for the Miata”.
Maybe I jinxed things.
While certainly not a terrible winter, it was plenty cold; too cold to spend much time in the unheated garage. But the calendar claims that spring is around the corner, even if the thermometer has yet to catch up. A few weeks ago, cold or not, I decided to forge ahead with the car’s #1 priority: the replacement of the rear brakes, including pads, rotors, and calipers.
The Mazda’s parking brake has been loose for a while, requiring a long pull of the handle before it would engage. Attempts to adjust it were for naught. It turned out that the piston in one of the rear calipers couldn’t be adjusted in either direction. Unlike the European cars I’m accustomed to, this Mazda’s e-brake operates directly via cables on the brake calipers, moving the pistons inward to contact the pads and apply the hand brake. Each rear caliper piston should be able to be rotated inward or outward as an adjustment.
All my Volvos used a set of parking brake shoes inside the ‘hat’ of the rear rotor, in essence giving you a drum brake within the disc brake. While it has its advantages, I’ve seen cases where the e-brake shoes rust and seize inside the rotors. When that happens, your first tool of choice is a large hammer, and the repair procedure reverts to incessantly beating on the rotor to free it from the shoes.
But back to the Miata. I ordered parts through my place of business from Centric. I had my choice from a number of reputable brake parts suppliers, and I chose Centric after learning some detailed information from one of their reps. He informed me that if one orders the LOADED calipers (with pads installed), the calipers receive an anodized finish, compared to the SEMI-LOADED (hardware but no pads) ones, which are cleaned, but are left with a bare metal finish. All the calipers are remanufactured (‘reman’) units, and carry a core charge, refunded once the old parts are returned.
I also stepped up for higher-quality rotors which have a black e-coating on the non-contact surfaces, to prevent rust. All the parts arrived last week, and initial inspection showed that everything looked copasetic. In order to get my core charge refunded ASAP, I used this most recent weekend to install the calipers.
Once the order was placed, but before the parts arrived, I removed the parking brake cables, and loosened all the caliper bolts, including the hydraulic lines, to ensure that I’d have no surprises during installation. Centric makes a big deal about reinforcing the message to the customer that the core return must include the caliper and parking brake brackets. I’d presume that would be obvious as they are included on the reman caliper, but perhaps not.
The job could not have been more straightforward. Centric even provides new banjo bolts and copper o-rings for the hydraulic fittings. Starting with the left side, I bolted everything up, but had a slight drip from the brake line. It turned out that one of the old o-rings was stuck to the line, and I hadn’t seen it. Once I removed it, everything snugged up and stayed dry.
Then I had the exact same problem on the right side, only there was no double o-ring in the way. To stop the drip, I had to resort to reusing the old o-rings. For some reason, the new o-rings are ever-so-slightly larger than the old ones. While it’s good for now, I will get to the store and buy new copper o-rings to make sure that I’ve got fresh ones installed. I’m still not sure why it’s leaking with the new o-rings, but I can get back to that later. Both old calipers, with the necessary brackets, are off the car, and are boxed up and ready to be shipped back to Centric, which I’ll attend to this week.
In the meantime, I placed an order for Valvoline “synchromesh manual transmission fluid”, which comes highly recommended for my five-speed by the guys and gals on the miata.net forum. Weather permitting, I’ll tackle that next weekend.
Looking for the next installment of the Isetta Saga? So am I. Once I find it, which should be during the upcoming week, I’ll spiff it up and get it online for your reading enjoyment by next weekend.
All photographs copyright © 2018 Richard A. Reina. Photos may not be copied or reproduced without express written permission.