- My model of MX-5 is:NB1
- I’m based near:Manchester
- I’m looking for technical help or recommendations on:Resolving Brake Issues.
4.After replacing the rear left caliper due to a seized adjuster I have had continuing problems with brakes binding after 15 mins running.
Today I returned home and found the front brakes were extremely hot by spraying them with water - much steam resulted.
After cool down I have bled both front brakes having bled both rears yesterday.
Im looking for assurance as a long trip is planned for mid september - Thanks
Regards
Nic Cox
You need to clean up calipers and slider pins
Already done, my friend.
If you have cleaned up slider pins, then the only other thing it can be is sticking pistons, so full rebuild or new calipers needed.
If you have the time rebuilding a front caliper with a new piston and seals is quite straightforward and very economic. I have done this on my son’s NA my old NB and now my ND.
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Thanks for your input everyone.Quick update.
From cold again this morning the brakes are fine then after a short drive 10 mins or so in urban conditions the brake pedal comes up and becomes hard. The car then progressively starts to drag. Once home you can smell both front brakes which are extremely hot before I hose them to cool down.
Once the car is left again for a short while all returns to normal.
My question and concern is why both front calipers, surely very unusal for both to lock with either piston or slider pin issues ???.Is there any other reason or component that could be causing this? (Note Ive got Goodrich stainless hoses on the calipers)
Ive just disassembled the front neareside caliper which apart from being warm and very tight on the pads seems quite normal. The sliders came out ok and dont appear warn (I only completely rebuilt the calipers 3 years ago). Ill check the piston movement later
From experience you might like to consider having a look at the flexible brake pipes. Exactly the same symptoms were exhibited on an Elan. One of the pipes was collapsing internally and creating a ‘one way valve’ situation. The pressure would build and then when you stopped using the brakes it would slowly release. This was on a new pipe, a replacement cured the issue.
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Thanks Malc,
I hadn’t thought of that one. As luck would have it I have a brand new set of OEM front hoses NA75-43-810A which I was going to fit in the future due to the locking pin inclusion at the caliper end which of course the Goodriches dont have:+1:
.
Regards
Nic
Rubber pipes can develop a flap if the metal end-fitting has carved a bit off the inside when being inserted at an angle.
I first came across this on my old Mk2 Farnham Estate Zodiac which suffered from intermittent fuel starvation, but only on full throttle. And alarmingly it only happened at the worst possible moments. Hence the car was a very cheap buy at £25 in 1969.
It was the 12" of rubber pipe between the hard line from the tank and the one on the engine going to the pump. An off-cut of reinforced plastic fish-tank pipe was a “temporary” bodge that lasted until I scrapped the car 30K miles and three years later.
Evening Malc, Thanks again for your consultancy 
.
Look what I found today when I removed the front nearside flexi 
.
Goodrich ss hoses fitted November 2021 at 68k miles I’m now at 75k miles so 7k miles and 4 years life.
Im grateful it didn’t result in something more serious I’d have been gutted.
Regards
Nic
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Good spot there Nic. Glad that my personal experience has been of practical use.
PS I was tempted to say ‘found in the nick of time’ but I resisted!!
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This could be caused by failure of brake fluid to return to the reservoir due to a blocked port in the master cylinder. The simple test is to drive until the problem materialises then jack up a hot wheel to see if the brake is binding, slacken the bleed screw and if hot brake fluid sprays out and the brake releases then the fault is in the master cylinder.
Thankyou for this,
I’ll bear it in mind, but it would appear at the moment that the problem is due to failed flexi brake pipes, I will know better over the weekend.
Regards
Nic
Going back some years now but I had a similar issue with a Mk1 Escort. Stopped dead on me at a junction, got out to look to see glowing red hot discs. Fortunately I lived just round the corner so ran home for a spanner to release the bleed nipple. In the end I replaced the master cylinder to cure the problem.
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You’ve been very unlucky here, especially if both Goodrich hoses failed so early in their life and at the same time. Or perhaps lucky, in that you didn’t have just one fail and make that side brake harder than the other.
How happy do you feel about continuing to use those pads, which have now been overheated multiple times and for a fair length of time?
Thanks for your reply.
On inspection of the Drivers (offside) Goodrich flexi there is heat damage midway along the hose. I need to investigate further to establish if there has been a core colapse as with the nearside.
I took the decision based on my Aeronautical Engineering background to Inspect the Calipers, I did this and at the same time replace all four slider pins. After further consulting on the forum I have also now replaced the discs and pads with Brembos whilst also returning to Mazda OEM brake hoses - Test Drive today, but it feels 100 % better on the pedal already.
Regards
Nic
2 Likes
Afternoon all,
For those of you following my Brake Issues, a further plea for help as Im now at the end of my teather and rapidly falling out of love with my pride and joy - HELP.
Following the replacement of all slider pins plus replacing all my discs and pads with Brembos - none slotted of course and reverting to OEM Brake Flexi s all round. I had a problem sealing the banjos at all four corners, this was solved by using oem banjo bolts and copper washers oh and the offside rear caliper due to a stripped caliper thread.
Now for the finale, I thought bleeding brakes was simples as Ive done it many times before in my 60 plus years😉.
In short after bleeding in the correct sequence there was some fluid at the rears but virtually nothing on the fronts - Ive used both conventional up/down bleeding and a one way valve with the same result.
With the engine off there is no pedal pressure, even with a bleed nipple open there is nothing at the pedal.when I start the car and the servo kicks in the pedalcomes up to rock hard after a few pumps, but the brakes are locked on at least the fronts are. I have repeatedly bled all to no avail.
Thanks
Regards
Desperate Nic
I now think its probably the Master Cylinder which is at fault.
Thanks
Nic
Yup, sounds like brake master cylinder is caput
Afternoon Everyone,
Re the above, Im advised by MX-5 Parts that the Master Cylinder for a 1999 NB with ABS Part Number N055- 4340ZA is No Longer Available NLA?
Can anyone confirm this and advise if the (NB2 FL) Master Cylinder with Low Brake Fluid Light is interchangable with the MK2 NB1?
Also has anyone repaired or fitted a non OEM Master Cylinder?
Thanks
Regards
Nic