Nylocs or split pins?

  1. My model of MX-5 is: 1.8_Mk2.5_
  2. I’m based near: Gloucester __
  3. I’m looking for technical help or recommendations on: _
    I’ve just replaced the lower & upper front suspension ball joint dust covers on my 5 (failed last Mot as they were all split!) .
    When I stripped it down I could not get any of the split pins out, so they now need drilling out or could I replace them with nylocs?

Is there any thing in the MOT regs that says split pins must be used or can I replace the castle nuts with nylocs?

As a rule of thumb, you should always replace parts with identical parts.

I’m surprised you can’t get the old split pins out… Can you just not remove them or have they snapped off and a section of the pin is jammed inside?

If the latter and its jammed, the last time I encountered that problem I gave it a really liberal dousing with WD40, and then heated it up with a blow torch, followed by punching the remainder of the pin out.

I reckon the blow torch will put you back to square one as it might damage the new dust covers…

So, do the above (minus the torch), and then get a nail that’s the same diameter as the hole that the split pin goes through and if you do it properly, you should be able to hammer the old pin out enough to grab it with a pair of pliers or mole grips and pull it the rest of the way through… Then just replace with a new one!

Also, not sure about MOT regs… If in doubt, give the MOT station a call and check.

I don’t think it would be an issue personally and I’d be inclined to do it and see what happens… But I always believe that things are designed in a certain way for a reason… Its usually best to adhere to the original specification.

I’ve replaced ball joints on older cars and the replacement parts have some times beensupplied with nylock nuts to replace the split pins. It’s cheaper to manufacture. Never had an issue with MOTs. I’m going back 20 years but don’t see why it should be any different these days.

Thanks guys for the replies, I’ve opted to take the risk at the MOT and go for nylocs, just to cold this morning to mess around trying to drill the sheared pins out!

I don’t see the problem. As long as you have clear thread protruding out of the nylon it’s a recognised mechanical restraining system just like a split pin. I raced for many years and replaced all roll pins with ‘R’ clips. In and out in a second to work on, but still passed MOTs. (Was a race series requiring an MOT to restrict modifications, ie tyres etc)

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Done this job three times on Mk1s/Mk2s. Ive always used Nylocs, and never had a problem on subsequent MoTs. I’m sure moderns don’t employ castle nuts/split pins.

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I would not use nylocs where it gets hot and oily.

I remember Mk2 Jag big end caps used split pins.
On one engine we did the previous bodger had not taken the extra few seconds to nip off the surplus and there were bits of broken split pin ends rattling around the engine.

Ball joints don’t tend to get hot so they would be fine with nylock. I’d they are getting that hot you have more pressing issues to worry about :see_no_evil:

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