Mk1 uneven braking, locking 1 wheel

  1. My model of MX-5 is: 1990 1.6
  2. I’m based near: __
  3. I’m looking for technical help or recommendations on: __

Hi all,

Have noticed my mk1 has started pulling to the left when braking. I found a quiet stretch earlier and tried a few hard stops and it repeatedly locked the front passenger wheel.

What could be the issue here? Air in system? Brake lines stretching? It was fine a few weeks ago!



Sticking caliper


■■■■■, were only rebuilt a year ago! Albeit by me…

Pulling under braking obviously not right, get it on a brake tester at an mot station?
Nsf brake locking first under hard braking I would say that’s normal both my Mk1 mx5 and Citroën AXGT do this if I stamp on the brakes.:laughing:

I might actually check tire pressures and then take for a proper drive, see if i can free things up!

If the caliper was sticking, one wheel would be obviously warmer than the other.

Yeah, just went for a drive and did a few hard brakes. It seemed to get better as i drove but the left wheel is much hotter than the right. I will check the sliders. I’ll also re-bleed calipers too

Weird as I rebuilt the calipers in Feb and they were fully greased up.

Also noticed my tire pressure gauge was obviosuly wrong. Tired were 21 and 18 at the front. Wasnt helping anything!

Oddly, for 15 years through a couple of disc renews and a few OEM pad replacements…and proper bleeds…my front nearside has always locked first, and that’s with proper & expensive rubber set to 26 PSI.
Years back a guy on a Club run said…“funny…mine does it too”
We agreed it may just be another Mk1 quirk…one of many.
Question of both degree and circumstance though.

Probably irrelevant, but some idle thoughts: Corner weighting? No passenger?

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Far from irrelevant, we reckoned maybe that was an element that as well.
I guess without ABS, something has to give in extremis so it’s not a stretch to imagine the lightest wheel has the least mechanical grip.
Guy I was speaking with built his own track day stuff…knew a thing or 3.

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Our old woody-mini was light, and when I bought it cheap for SWMBO immediately after she passed her test, it was something that didn’t matter if she trashed it. I wanted to keep SWMBO in good health, so I made sure suspension, brakes and steering were perfect, and the five matching retreads it came with were brand new (so should be OK, I thought).

However because the engine was knackered she soon learnt that the only way to get anywhere was with a leaden right foot, and with all the heavy late braking she repeatedly locked all four wheels.

Only a month later when I next drove the car again to get four good “named tyres” it felt like it was on four of the ancient thrupenny-bits because of all the flat spots, and the two front tyres were down to canvas in a couple of places.

The “named tyres” solved the skidding problem, and lasted for ages.

Is the disc bluing? Front brakes will always get warm. The converse scenario is that its the other brake thats not coming on. If that wheel is stone cold after a run, there is a problem. If the other wheel is getting excessively hot, you can see changes in the disc.
The mechanic’s convention is if one caliper is going the other is not far behind, hence replace both discs. Not that I have had that problem. I’ve had mine so long, I’ve started on the 3rd set of calipers (giving up with the remanufactured ones, moving to pattern new calipers).

Discs seem fine. Ive hardly driven it recently due to clutch issues (now fixed) and have noticed it on short trips (no more than 10 miles) in the last week or so.

I did a track day in it in April and it was fine and have done several long journeys since. Only happened after it was sat for a few weeks.