Protecting new brake disc backing plates?

Technical Area Wheels, Tyres & Brakes
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  1. My model of MX-5 is: 3.5
  2. I’m based near: Glasgow
  3. I’m looking for technical help or recommendations on:

I’ve just received new front disc backing plates and before I fit them I want to see what I can do to protect them somewhat, since the originals are absolutely disgusting after 11 years.

To hand, I’ve got some:

  • Clear lacquer
  • Dynax UC (worked a treat on the suspension arms and coilovers)
  • Por15 and Top Coat (used this successfully on new control arms)
  • BBQ black spray
  • Engine enamel

What would you do or use to give them the best chance at longevity and staying in good condition? Was wondering what the best way to key the metal for any of the paints to bond since the plates are quite thin?

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With proper prep underneath they’ll outlast the car. (Read the relevant instructions on that particular tin/can of E-E.)

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I’d use smooth Hammerite paint. It’s pretty resilient and the rattle can version is easy to apply.

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Got some myself recently, I’m going several coats of hammerite after a light scuff with emery to key the plates.

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Trying to use what I’ve got lying around so it’ll be engine enamel.

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POR15 should be more than fine, just dont get it on your skin as it will not come off

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Anything will do, far better than the thin layer of black they put on.

I sprayed mine up, already had the paint. Scuffed them up and 3 coats of primer followed by 3 coats of black then a coat of lacquer.

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Since you already have POR-15 and Dynax UC on hand, you have two of the best options for long-term protection right there. Using a combination of these is the ideal strategy for longevity.

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It is annoying that such components are so shoddily finished but I suppose it’s an accountant’s decision rather than the production engineer! The finish on Japanese motorcycle stands and frame parts in the 70’s was shocking, you were lucky if they lasted 3 months!

Anyway, would it be worth getting the backing plates powder coated or are they too thin?

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Great thread. My 2018 fronts look like crap so I’ll be planning on doing this when the front discs next need done. I should also have the calipers refinished too as they just look like bare steel.

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I would add to this thread, if you’re replacing the front brake shields NC’s I would also invest in a new pair of front hubs too. They are a pig to get off and in doing so (myself) had to resort to much bashing (along with a made up tool) to remove to them. Higher mileage cars I guess it would make sense to renew anyway. The ND hubs I’m unsure of, they look pretty similar to the NC.

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I’ve got a slide hammer which should make it easier to get the hubs off and I’ll assess the condition of them and see if there’s any play once the brakes are off. Should be easier getting them off next time anyway once they’re cleaned up and a slither of copper grease applied.

I’ve gone with the engine enamel spray, 3 coats in and looking good. Will do another couple of coats then bake them in the oven for a bit. Will spray down the backs with a bit of Dynax UC when fitting. I should/could probably have gone down the POR-15 route but the heavy rain and dropping temperatures would affect proper curing.

Forecast for the next week is rotten so I’ll ambitiously be fitting them whenever I see a couple of hours break between downpours.

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Pair of Febi front hub bearings being delivered tomorrow, £94 the pair from CarPartsInMotion on ebay with the 20% off code. I didn’t fancy £360 on OEM bearings but £94 is easier to digest and hopefully Febi still make good quality parts.

Car’s on 72000 miles so makes sense to renew while they’re off, as you suggested. No harm in putting the old ones on the shelf for an emergency.