NA Brake change woes

  1. My model of MX-5 is: NA
  2. I’m based near: London
  3. I’m looking for technical help or recommendations on: Brakes

After a driving trip to Scotland i decided my 1.6 brakes were pitiful … I know i thought , I will upgrade them to 1.8 brakes as my friend on my trip had that car and the braking was way way better

So i purchased 4 discs, pads & a set of carriers … however i have run into some woes which i need help with

  1. Brake bleed nipples … the nipples seem really small and i can’t find a flare nut wrench for them … it looks like the front take a 8mm spanner and the rears 7mm ? any advice on the right tool and general experiences with these small brake nipples … any better alternatives / bigger size etc

  2. 3 of the nipples are on tight and i think if i use a normal spanner i will strip them … which is strange as the previous owner said he bled the brakes last year and i do believe him … any advice

  3. rear left caliper … this is brand new (like 3 months old and was fitted by previous owners garage) … i followed a good DIY guide and got to the point to unwind the caliper… i am certain when unwinding the allen key the caliper barely retracted … after a few turns the allen head with splines on it came out of the caliper … have I done something wrong … as it stands that although i can push the caliper with the new pads back on, its way too tight and will definitely bind unless i back it out some more … i cant see if i push the allen spline bit back in how it would miraculously reengage and work???

Firstly the car was not under braked, so if you are having issues, it will either be poor pad performance, or more than likely maintenance required of the parts you have there. The relevance of this is that you are putting the most important part of the “job” (callipers) back on the car. It is highly likely that these were underperforming in the first place.

Tools wise, the answer is simple, get the right tools.

Rewinding the callipers, always push them back at the same time, either with reasonable continuous force or push and then wind the tool, push and then wind the tool. If you have access to a lathe, you can turn the damaged end off the spline key.
All that said, if you are having issues with the rear callipers (and the fronts are probably in the same condition) then you probably have found the cause of the poor braking performance.


Thanks Nick … couple of questions

get the right tools - i’m looking for a tool recommendation - even a cursory google doesn’t show a decent flare wrench in 7mm and most sets only go down to 8mm … what are other people using for their 7mm fittings?

Also the caliper in question is literally new (fitted Feb) - the spline key that came out looks totally undamaged - i will reinsert it and try again as you stated … all the videos i saw were rusty old calipers being wound and unwound without any forcing or pushing

i agree that possibly the front calipers are all shot (there was rust around the piston) that i sanded off so that might be a false economy

again looking for a recommendation of what calipers to get (MX5 Parts sells a few different ones) but are you getting more by paying more?

Since you can get a full access to the head you are better off with a ring spanner to loosen them and then just an open ended spanner to nip them up when bleeding.


I got my hands on a set of MK1 1.8 calipers and they are now for sale cheap on ebay as I have no use for them. In truth they all require refurbishing cosmetically and I would recommend new piston and seal kits. One of the things I did before listing was to free up all bolts including the bleed nipples. The bleed nipples are 8mm on the fronts and 7mm on the rears, standard; not the easiest sizes to apply torque to. I spent a couple of days soaking them after trying to clear as much of the external corrosion on the thread links as possible. Ended up using six sided ring spanners and would not advise twelve points for this job. I think the ideal tool would be a long socket with torque applied to the centre to avoid lateral pressure that could easily snap the nipple off.
Take your time, applying penetrants days before you attack these preferably with a tool I did not have to hand. Whilst these are off the car, check the seals and pistons carefully and consider replacing. Kits are reasonably cheap and assuming the rest of the functional part of the caliper undamaged and free of intrusive rust, will be functionally like new calipers.

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Thanks Nick, really appreciate the advice and link … the smallest i had was an 8mm so will use that too

what about caliper supplier recommendations ? is there a “goto” place or will anything from MX5 Parts etc be ok ?

Autolinkuk, MX5Heaven, Moss

After having a Brakes International front caliper seize on my after a few years, I decided to buy a new caliper from Autolinkuk. Seems fine, and Autolink are sourcing them from a reputable UK company. Much cheaper than recon.

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There’s these from moss … includes carriers too … too cheap to be true??? …thoughts ???

includes pads and discs.

I recently purchased a “new” caliper from Autolink; it came from DJA Auto International

Moss is a subsidary of a US parent. They sell a number of replacement aftermarket calipers, but won’t give the suppliers name:

Might be the same, as these come with the carriers as well. Looking at Rock Auto listings, in the States, 1.8 calipers nearly always come with carriers.

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thanks for all the responses… I have ordered 4 new calipers from MX5 Heaven … i went for the “middle of the road” in terms of perceived quality by getting NBK items … not OEM, not cheap,

I bought these …

Laser Tools 6498 Brake Bleeder Wrench 8mm

Laser Tools 6497 Brake Bleeder Wrench 7mm

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thanks @Bob_M1 … i bought the 7mm … found an 8mm bleeder wrench in the garage from 25 years ago which also works a treat!