Hi,

I posted a while ago trying to work out what tie rod end to use on my MK5 NB front hubs, but no-one had any ideas. A BMW part fits the MX5 NA hubs, but not the NBs. I've been on a trawl through the Moog parts bin. This PDF shows what they have (massive download!).

However, in the measurements (pg 1601) they only show the diameter of the fat end of the taper that goes into the hub. The thin end diameter or the length of taper are not shown.

I'm assuming that this matters a lot - but are they standardised or something? Is there something I'm missing?

Cheers, Geedle.

Forgive me if I've got the wrong end od the stick (or wishbone) but if you are talking about a ball joint for where the upper wishbone meets the front upright you can buy them for £20 at http://www.mksportscars.com/mk-indy-rx-5-top-ball-joint-drag-link.html

They are Ridex part number 914T0184 which are available (though often shown as out of stock) from other suppliers for less than £5 plus postage

Those work for MX5 NB uprights? I've spent ages trying to work find something that would work without reaming out the uprights. Thank you!

I'm fairly sure they are good for the NB - I hope so, my donor is a 2004 Mk2 1.6. I've literally only just bought them but if you give me a few days I will check them out.

Too late - just bought single cheap ebay one for mock up. Hope it fits!

The Ridex part number given matches the BMW 3 series track rod end given by Saturn Sports Cars when they redesigned the Roadster chassis to take the MX5 parts.

The SSC amendments were done with NA running gear.

The difference between the NA and NB uprights is that the taper is much thicker on the NB than the NA. The exact difference escapes me but it's something like 6mm.

The top diameter is the same on both NA and NB uprights, the taper angle appears the same as the bottom diameter is smaller on the NB compared to the NA.

On the NA there is plenty of exposed thread when fitted. On the NB the thread barely (and I mean barely) breaks beyond the nylon of the nyloc.

I do have a photo of the track rod end in an NB upright, but I keep getting an SQL syntax error when I try and upload...


Mazda changed the balljoint length from the NA to the NB. There are lots of threads on Miata.net and SpecMiata talking about it.

ETA: I ended up designing a tapered pin, I spent ages trying to find a slightly longer version with no luck. Never got round to getting it made up though as I sold up the project.

Phil at (the now defunct) Talon suggested machining the underside of the taper down to mimic the NA arrangement.

[Edited on 27/11/20 by PorkChop]

Thanks Pork Chop for shedding more light on this. Following Geedle's trust in my reply I thought I should check quickly if I have the right part.

Today I took the top wishbone/ball joint assemblies out of my MX5 upright and they look right to me, except perhaps that the tapered section appears shorter which I think is because when you fit them the the rubber boot is pushed up the taper to make a seal at the top - the wire ring would expand to accommodate, the tension making a tighter seal. I didn't tighten them up because I want to do that just once when I assemble with my custom wishbones. It looks like there is enough thread and I will check the diameter of the taper near the thread, and the same number of mm away from the thread to check the angle - or maybe wrap and glue a paper cone over the taper to check they are the same. I'm not sure if I understand your "taper is much thicker on the NB than the NA". Maybe I'm wrong about the rubber boot pushing up the taper making it longer....

The original assembly has a split pin through the threaded end which I like. One of the ones I bought came with a nyloc nut, the other with just a plain nut (MK, shame on you). My view is that so long as the nuts go on fully then the right specification of Loctite should give peace of mind.

Geedle, I'd welcome your feedback when you get yours. Well done for just getting one to try!

It is just a cheap nasty ebay one. I'm happy to give it a go machining it (any excuse to break out the lathe) if it really won't fit. However I can't see how you'd disassemble a ball joint non-destructively for machining. I've just replaced a ball joint on my daily driver: I might take the old one to bits later and see how they work.

Thanks Geedle, as I said, I'm pretty sure the taper nearest the thread is the same but I can check this. Key point for me, so long as the taper angle and the diameter of the taper at the thread end are the same the original, when you cut away the boot, is the tapered section as long as the original? Rather than taking it apart (I've being taking thinks apart since I could walk, not so good at putting them back together, so I appreciate your thinking) how about inserting it in your upright and seeing how how many turns of the nut you get from hand tight to full tightness? This will tell you how far the taper goes up beyond the length visible before installation?

I'm with you - will do. Photos to follow.

The other option is to use NA uprights. I've put this project down for a while, partly because of this problem and partly because of the motorhome build. But I seem to remember the NB uprights were better if you could use them. Something to do with track rod ends.

Ok, I've done a bit of measuring. Firstly, it's easy enough to push the boot up towards the ball joint by hand so I am happy the taper is long enough. Now the bad news.

Carefully measuring, the small diameter by the thread is 12.5mm compared to 12.3mm of the original. This would be okay in my view if the taper angle is the same. But measuring the taper diameter at 15mm up from where the taper ends, using arctan to find the angle gives 3.25 degrees taper (6.5 degrees total at the top of the cone) compared to 2.75 degrees of the Ridex part - which means the part simply won't work, touching only at one point exacly where the taper ends near the thread. The gap at the top would be 0.15mm which doesn't sound like much, but I don't fancy trying this. A solution would be the machine the hole in the upright to have the same diameter at the top and a larger diameter at the bottom - the taper length is actually long enough for this and it'd give room for a washer at the bottom which is good for several reasons. I'm wondering if this could be done with a tapered reamer - it's not a lot. Or could be done on a lathe with axes moving together I suppose....

Sorry to have lead you down the wrong path....

Yeah - that is pretty much where I got to last time round. Some people have found that there is a reaming tool designed for woodwork which is the right angle. The one designed for metalwork is quite expensive. Maybe we should look at splitting the cost of one...

Well, it's better to find this out now than getting too far down the path....

I do favour splitting the cost of a proper reaming tool as this is a good solution from which others might benefit as it seems nobody can say for sure what ball joint to use for the NB.

Do you know where to source? And should we check the taper angles more accurately before committing to the reamer angle? Also, you sound like you have (access to) a machine shop? I'm in Surrey, you?

Cheers
Adrian

Have a look at this video and see what you reckon:

https://www.youtube.com/watch?v=Y-lGJ0DAiVc&t=318s

As with regard to sizes, I'm sure I had found it as some point in the past, but I've no idea what it is now.

Nice video, gives me a raised level of confidence that reaming should work. I'm surprised it can be done so quickly - when I was reaming cylindrical suspension bushes 40 years ago I remember doing it by hand and regularly twisting a tad in the other direction to clear the swarf.

Main difference is that he is just reaming the same taper angle to a bigger diameter whereas we need to taper a smaller angle which will mean starting cutting at the lowest point and slowly moving up cutting a longer length. Would probably be best done by hand which will take a little longer, and it may wear the reamer unevenly which will shorten it's useful life.

Interesting that he's comfortable re-using the nyloc - at least he's using loctite.

I'm back to thinking, how to check the taper for sure, and where to source a reamer at a reasonable price

This is the Moog parts catalogue. If you look at it from page 1601 on, it has the ball joint dimensions. So if we can work out which one is the Transit one, we should be able to work it out the taper. However on the UK parts catalogue, it doesn't give this figure, or enough other measurements to work it out. Moog's US site does give enough measurements, but everything is imperial and the part numbers are all different.

I did spend quite a bit of time identifying potential alternatives from the Moog catalogue, with the intention of speaking to my friendly local auto factors to see if they'd let me try some in the uprights. Then covid struck and I got no further.

Thanks, I've had a trawl through the catalogue - there are surprisingly few ball jointed tie rod ends with a male thread. The dimensions from page 1601 seem to ignore the taper angle, the one dimension we really need, unless I have misunderstood?

I found on the locostusa site a post which was asking if a Ford Pinto ball joint would work as it's described as having a taper of 8 to 1, see http://www.locostusa.com/forums/viewtopic.php?f=5&t=20728 and this ties in with the possible error in my measurements.

I'm now torn between reaming and finding the right ball joint. As far as taper angle or taper ratio (the same thing, just cotangent of the taper angle) is concerned, it seems to be really hard to find that dimension both for taper reamers and for ball joints.

Keep up the good search!

Cheers
Adrian

I would really like to find an off the shelf ball joint, just so that you can throw factory parts at it when it breaks...

I agree, but in case we want to ream, see
https://www.zoro.co.uk/shop/cutting-tools/hss-taper-pin-reamers/hss-straight-shank-hand-taper-pin-reamers-inch/f/278

I'm fairly certain the 3/32" HSS S/S St/Fl Hand Taper Pin Reamer is the one. My measurements are not perfect but I came pretty close to this and the 5/32 and 1/8 either side are way off. I've filled out their contact form to ask if they think this will work

Cheers
Adrian

quote:

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Originally posted by Replicar328
I agree, but in case we want to ream, see
https://www.zoro.co.uk/shop/cutting-tools/hss-taper-pin-reamers/hss-straight-shank-hand-taper-pin-reamers-inch/f/278

I'm fairly certain the 3/32" HSS S/S St/Fl Hand Taper Pin Reamer is the one. My measurements are not perfect but I came pretty close to this and the 5/32 and 1/8 either side are way off. I've filled out their contact form to ask if they think this will work

Cheers
Adrian

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Thanks David, it seems I've really not understood. It is so frustrating that nobody seems to offer tapered reamers with different taper angles, or if they do they are keeping it to themselves! Are you able to point me towards a supplier who can offer reamers with different taper angles? I feel sure that others must have been down this road before...

I dragged the upright inside to do some measuring:

• top dia: 13.86mm
  
• bottom dia: 13.17mm
  
• height: 18.99mm
  

Maybe there's a typo - the numbers you give would give an angle of 2.08. If I increase your large diameter or reduce your small diameter by 1mm (either works) I get to your 5.1 degrees. By the way, for small (half) taper angles which these are, the taper angle in radians is the difference in diameters divided by the height. Convert to degrees by multiplying by 180/pi , or 57.3

But that doesn't solve the problem! 5.1 is much closer to my measurement of the Ridex tie rod end which I get to be around 5.5 degrees than the original Mazda ball joint which I make 7.1 degrees. A diameter error of 0.12mm (either by you or me) brings me to 5.1. Weirdly, this suggests that my Ridex ball joint would probably be right for your upright!

Have you tried measuring the taper of the tie rod end you just purchased?

Cheers
Adrian

It is not here yet. Maybe the best bet is to put it in with some engineers blue and have a look at the contact patch...

quote:

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Originally posted by Replicar328
Thanks David, it seems I've really not understood. It is so frustrating that nobody seems to offer tapered reamers with different taper angles, or if they do they are keeping it to themselves! Are you able to point me towards a supplier who can offer reamers with different taper angles? I feel sure that others must have been down this road before...

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I may be wrong ...and often am... but I think the conventional taper measurements are inches per foot in old money and not degrees etc. Mot sure if there are more modern standards

A rough translation of the measurements given is 0.25 " per foot

Might give another way of reverse engineering this.

Many thanks David. They are indeed not cheap! I guess this is a last resort, I will re-double my efforts to find a tie rod end with the correct taper. I'm even thinking of designing a wishbone into which the Mazda top joint can be pressed although I'm concerned that it's only a tight press fit. I wonder if anyone has tried doing this...

Cheers
Adrian

Thanks "TheShed" - I suspect I am wrong more often! In this case you are probably right

Those are rather pricey, but it may be the solution.

My cheap eBay track rod end arrived (eventually!). Ridex part number 914T0184 (but a cheap pattern version of it). The taper seems to be right. When fitted snugly, the threads protrude 13mm through, so it is possible to get it good and tight. However, the upright is 18mm thick where the track rod goes through. I reckon that 11mm of the pin is in contact with the upright. The conical part of the pin certainly can't protrude from the hole in the upright, because if it did, it would not be possible to pull the pin in tight with the nut, but I reckon it should be a couple of mm shy rather than 7 or 8mm.

I am not familiar with the MX5 uprights, so this might be a nonstarter. But is there not an option for you to drill out the tapered hole so it's no longer tapered - put a bolt through and use a rose joint instead of a track rod end?

I was at AB Performance recently and Andy Bates suggested I do this to replace the tapered fitting track rod end on my Sierra hub/Escort steering rack setup. In my case it was to enable bump steer to be adjusted more easily than shimming the rack, but could you apply the same solution in your case?

quote:

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Originally posted by geedle
Those are rather pricey, but it may be the solution.

My cheap eBay track rod end arrived (eventually!). Ridex part number 914T0184 (but a cheap pattern version of it). The taper seems to be right. When fitted snugly, the threads protrude 13mm through, so it is possible to get it good and tight. However, the upright is 18mm thick where the track rod goes through. I reckon that 11mm of the pin is in contact with the upright. The conical part of the pin certainly can't protrude from the hole in the upright, because if it did, it would not be possible to pull the pin in tight with the nut, but I reckon it should be a couple of mm shy rather than 7 or 8mm.

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quote:

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Originally posted by jps
I am not familiar with the MX5 uprights, so this might be a nonstarter. But is there not an option for you to drill out the tapered hole so it's no longer tapered - put a bolt through and use a rose joint instead of a track rod end?

I was at AB Performance recently and Andy Bates suggested I do this to replace the tapered fitting track rod end on my Sierra hub/Escort steering rack setup. In my case it was to enable bump steer to be adjusted more easily than shimming the rack, but could you apply the same solution in your case?

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Correct me if I'm wrong, but aren't they Ford Transit Mk2 "Drag Links" NOT Track rod Ends.

I think if you check you'll find there's a difference in the design between Drag Links and Trad Rod Ends.

To expand, I think Drag Links generally have a male thread and Track Rod Ends have a female thread.

Drag Link



Track Rod End




[Edited on 21/12/20 by nick205]

quote:

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Originally posted by nick205
Correct me if I'm wrong, but aren't they Ford Transit Mk2 "Drag Links" NOT Track rod Ends. I think if you check you'll find there's a difference in the design between Drag Links and Trad Rod Ends.

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quote:

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Originally posted by PorkChop

quote:

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Originally posted by nick205
Correct me if I'm wrong, but aren't they Ford Transit Mk2 "Drag Links" NOT Track rod Ends. I think if you check you'll find there's a difference in the design between Drag Links and Trad Rod Ends.

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You're right and wrong.

M18 drag links for the Sierra version.

M14 BMW track rod ends for the MX-5 version (originally Saturn Sports Cars' suggestion, which as far as I've seen the vast majority have followed).

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I found that there was enough thread by a long way, but the lack on cone contact area is a bit worrying.

[Edited on 21/12/20 by geedle]

I need to get thinner nuts for my top ball joints, does anyone know what the thread is at the end of the taper after it has gone through the upright ?
I cut my nylocks down, but wasn't able to keep the nylock end so have to try again

Jason

quote:

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Originally posted by geedle
I found that there was enough thread by a long way, but the lack on cone contact area is a bit worrying.

[Edited on 21/12/20 by geedle]

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quote:

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Originally posted by Deckman001
I need to get thinner nuts for my top ball joints, does anyone know what the thread is at the end of the taper after it has gone through the upright ?
I cut my nylocks down, but wasn't able to keep the nylock end so have to try again

Jason

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I removed the rubber boot to make the photos clearer. Remember this is the cheap nasty eBay one, so it could have longer threads on it.

Pressed in as far as it will go - lots of cone still showing. Does not seem to rock though, which would indicate correct taper:
TRE1

Showing taper still exposed:
TRE2


If anything, I think the code may be too long. If the cone is longer than the thing it is going through, it won't be possible to use the nut to tighten it such that it won't work loose:
TRE3

Edit: I've put links in to some images on Google drive. I can't get the photo archive to work.

[Edited on 21/12/20 by geedle]

[Edited on 21/12/20 by geedle]

quote:

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Originally posted by geedle
It is not here yet. Maybe the best bet is to put it in with some engineers blue and have a look at the contact patch...

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