They should be loctited I believe so they remain tight.
Hello Richard,
I’m new member here and I am very interested of what you mentioned about brakes and calipers.
My story is that I have this kind of boring thing since I bought my new NDRF in 2018.
The very first kilometers when I left the Mazda dealer I told to my wife that the make a not normal noise from the back.
It was the beginning of a long story concerning this noise.
One week later I took an appointment with the dealer and the work chief told me that in fact it was not a normal noise ! So now and to avoid the stories with 3 other Mazda dealer, I hired and car expert paid by my insurance company. This expert asked the visit of an engineer Mazda Europe. I did not assist of the meeting because of my busy work but after this meeting “my expert” told me that good news because Mazda engineer told him and confirmed that noises come from calipers and this guy will complete the file concerning my NDRF.
After one week waiting we received an answer that the file was closed and Mazda doesn’t have solutions?!! Now I am back with all these efforts destroyed. I will try to find a solution by myself as you did but anyway I really surprise that not a lot of owners complain about that in Belgium or France.
Regards
Mitch,sorry about my English
Hi Mitch,
Your English is absolutely fine, no problem.
I bought my ND from a dealer about 100km away just before the pandemic struck, hence going back for them to examine it (they offered) wasn’t a practical option. I was puzzled for some time why I didn’t pick up the noise when I did quite a long (20km) test drive, then a possible reason occurred to me. The test drive was with brake discs and pads that had probably done about 78,000 km and the dealer kindly replaced all the car’s pads and discs free of charge before I took delivery. The reason the caliper has sliding pins is to allow for wear, as the components lose material, the pins effectively retract into the bore of the caliper which gives them a more stable location with the greater length of engagement. I believe that’s why it didn’t clonk noticeably on the test drive. In a slight moment of frustration I even considered having the pads machined back… didn’t do that of course.
Interestingly, my other car, a Seat Leon, also clonks from the back, probably for the same reason, but farther from my ear and much quieter, trouble is I notice it now!
Best of luck, Richard
Phil. You got me kind of worried now. How common is this fault, and if out of warranty what are people doing about it, what the cost for a new hub? Are there any particular models to loo out for please? As a potential ND buyer I’m worried to be honest?
They are my most local Mazda buddy so I’ll look hard at the MX5 they may have coming up?
I had a similar noise. After 2 years and no joy from any garage, I jacked up the rear to check the brake callipers. At this point I noticed a couple of plastic caps / shrouds on top of the shock absorbers, which were a bit loose. Plyed with grease as an experiment - no noise for the last 18 months. Pryor to this it was loud enough to attract the attention of passing pedestrians, even at slow speeds. Worth a look, before spending!
Good morning Richard,
I still have the problem of rear knocking on my NDRF. When I check the pins calipers I do not now the good position, which one have to be on the top!
The fact now you put suzuki ignis pins resolves the problem of the knocking?
Thank you
Mitch ndrf 1.5
Hi Mitch, Some months have passed since I last looked at the ‘clonk’ issue. Since your NDRF is a 1.5 and clonks, it’s likely not directly the result of stiff springs, lower profile tyres, Bilstein dampers or LSD on my car.
I’ve since seen another suggestion that was worth looking at more closely. Drive shafts.
Using a bump that usually provokes a noise I did a number of tests. At 20mph (30kph) and steady speed/throttle it clonks. At 20mph in neutral it clonks. At 20mph with heavy acceleration the rear wheels bounce and it clonks. At 20mph but accelerating very gently in 3rd gear it’s silent, pretty consistently, but it needs just enough throttle, too much causes momentary loss of traction and clonking.
I was puzzled that I never heard the noise on the test drive in the car. Here’s my theory. The difference between a CV on RWD car vs a FWD car is that it will operate at the same shallow angle almost all it’s life. I imagine the potential for localised CV wear and hence a little bit of free radial movement is greater in the MX5 than a FWD car.
The salesman came with me on the test drive, and he was a large chap, perhaps 100kg+, The combination of his and my weight (84kg) was probably enough to stop the rear of the car bouncing over bumps, hence fewer clonks. I can and will check this when I find a suitably heavy person to assess the effect. I may need to make that request tactfully 
Or use a few sandbags, but they don’t get themselves in and out of the car…
Thx for your quick answer,
Sandbag already tested for my part but did not change this boring knocking.
I am really tired now about this noise.
One more time today I changed the position of the pins calipers. The pins with flat faces is now placed below. Test drive after the work is not conclusive 
And snow tires do not provide any improvement…
A big part of the problem is the car is so quiet otherwise. I briefly had an NC before this one, it was generally much noisier. With the roof down in the ND a lot of other noises are drowned out by the wind noise.
The car handles fine so it’s become a minor irritation these days.