Non OEM front caliper

Technical Area Wheels, Tyres & Brakes
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  1. My model of MX-5 is: 2009 NC
  2. I’m based near: Bristol

Hi all

I’ve got a binding front right brake caliper.

I service the sliders every year when bleeding, so it must be the piston sticking.

I was sorting of expected this because the front left started sticking 2 years ago, which I replaced with a reconditioned OEM unit.

This time, however, I have taken a punt on a new “Ridex” caliper which was £49 including delivery.

Apparently they are a German firm and the caliper meets exactly the same requirements as the original.

It looks fine. The casting looks just as good as the OEM caliper which, let’s be honest, was nothing special.

The piston and seals look good, to me they do anyway.

So, I’ll pop it on and see how it goes and report back!

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Looking forward to hearing how it goes.
Good luck. :+1:

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There are threads about remanufactured versus pattern. Over the years, I’ve been through a few calipers, tending to default to remanufactured genuine (Sumitomo) calipers, but a few years ago, supplies seemed to be drying up (I suppose they are running out of good cores). After a Brakes International front caliper seized on me after just a few years, I went with a new pattern caliper that I traced back to a UK warehousing operations. The caliper has been fine.

Ridex is a brand of Autodocs, and they source remanufactured parts from Czechia and new parts from Turkey and South East Asia. All of these new calipers sold in Europe are coming from China, but you hope the warehousing/reboxers here due their due dilgence somewhat better than someone shopping for parts containers on Alibaba and selling on Ebay.

There is actually very little regulation of aftermarket parts.

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Thanks for that info, you’ve certainly researched the alternatives more thoroughly than me.

Hopefully I’ll get it fitted tomorrow morning before the storm arrives.

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It must be material quality with these pattern parts as calipers are mostly just a rough cast piece of metal and machined for mounting points and pistons etc. They copy the original part exactly most of the time. If the steel used is a different type or a lower grade it could rust out the piston sliding surfaces or expand and contract at different rates to the oem stuff. That being said, it seems that oem calipers seize up anyway, and if it gets you going again for little money who’s to argue.

Bit like with bmw and their wheels, purists would say ‘don’t buy replica wheels, they’ll crack’, when oem wheels are notorious for cracking. It becomes a question of do I want to pay less for something that will probably eventually fail or pay more for something that will also probably eventually fail. You pays your money and makes your choice.

My old 545i wheels had cracks on them when they were removed that I never knew about. I fitted replica m3 wheels and never had an issue in another 4 years of driving…

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Obviously the casting isn’t exactly the same, otherwise Brakes International and others will be refurbing pattern parts.

The castings, whether pattern or genuine Sumitomo, are pretty rough on the exterior. I suppose the difference is the precision of the machining of the bores to ensure a precise seal fit, and that, in the past, probably came with a cost, because of the tooling needed. Now, perhaps that is less of an issue, because these aren’t machined by a machinist, and spot checked anymore.

How fake Brembos are made in China. It looks to me like a pretty decent factory.

Mexican remanufacturing

Very expensive CNC caliper manufacture in the UK

I suspect the Sumitomo factory from 30+ years ago churning out MX5 calipers looked much the same as the Chinese caliper factory looks in 2024.

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The difference I’ve noticed between pattern calipers and genuine ones that I’ve changed is mainly simply a lack of the oem manufacturer name or part number. Sometimes you can even see where the logo or name would of been on an oem one but when they’ve cast or molded it it was ground off or filled in either before the mold was taken or after for copyright etc. I’m almost certain they take casts from originals having seen them side by side, makes sense for the pattern parts aftermarket to use the oem as a blank for rough casting them machine them, rather than design and make one of their own from scratch. I’m any case, I’d agree that oem would always be best bet but if they’re prone to seizure and the price difference is significant as it is, I’d take a punt on the pattern part.

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Mazda charges a ridiculous price for Sumitomos; £230 each for fronts and £209 for rears (even though the rears have more parts…). Thats 4x the price for >30 year old design. The first caliper I had to replace was a rear caliper on a 7 year old NA, after the adjuster wore out. Back then, it was a 2 week turn around on a reconditioned caliper, there were no remanufactures in stock, and literally Mazda would refuse to sell import owners anything. MX5parts was still Scimitar International, selling Reliant parts to MX5 owners, and Moss were the only team in town.

I don’t recall any distinctive marks on Sumitomo calipers.

OEM are rough cast as well. How many times have they remade the mould?

OEM and pattern then take the casting and machine it to accept the piston, bleed nipple and banjo connector.

I’ve been told Mazda (Sumitomo) make licensed copies of Lockheed-Girling brakes, pretty much the same as fitted in Rondas and some VWs, with the same issue.

So the IP lies with Lockheed-Girling not Sumitomo, and that patent expired eons ago.

The reason why the OE marks are not visible on a pattern part is because a pattern part is not a fake or counterfeit parts. Its not being sold as “genuine Mazda”. In fact, if one’s only check if a part is genuine or not is because of the existance of a casting mark, one could be in trouble.

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Where it gets murky is in the BS from some reboxers; that the part in their branded box has come from the same factory that Mazda gets their part from. Even if that were true, its not the same part. Its a part made for them, to their specification.

I had a conversation 20 years ago or so with Bilstein about the Bilsteins on Mazdas. They were admant that these shocks were made just for Mazda, and you can only buy replacements from Mazda. Of course, Bilstein can sell you shocks to fit your car, but they are built to Bilstein specs, not Mazda specs. Even more, you can buy Bilsteins that are not assembled by Bilstein. Ennenpetal is a Japanese dealer. They get the Bilsteins in kit form and reassemble themselves. Some parts are completely different (different threads etc).

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Fitted the Ridex caliper today.

Everything lined up fine, and after a few emergency stops all is well.

It was good to find that the bleed nipple was only nipped up.

On the reconditioned OEM caliper I purchased a couple of years ago an over sized nipple had been fitted and it lwas so tight that I thought I was going to snap it when loosening off to bleed the system.

Presumably the old caliper had a snapped nipple.

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LOL. Forget all what I said about calipers. Jumped in the car today for a 100 mile drive to Leicestershire, expecting to enjoy some fine weather. Got about a mile before it was clear something was wrong, when trying to pull up at a roundabout. Front wheel, with the pattern caliper, red hot. Nursed it home, though it seemed fine by then. Revert to the XJ8.

Sigh, now do I attempt to clean up what is probably a rusty piston or not bother, and just put on another disposable one. Brand new sliding pin. Lasted just over 3 years (Feb 2021) and 6,000 kms. No hint of anything at the November MOT. Car had sat for last 3 weeks on the drive as I was repainting the boot lid in the garage, and wanted the lacquer to get a good cure.

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