Suspension arms, Subframes, geometry and bushes.

This article is for the hardcore enthusiast, if you’re Mr or Mrs 2006 100k miles ‘I’m not spending that much on a £xxxx car!’ you’re probably best off not knowing what is written below.

If you’re looking for suspension settings this isn’t really the place either, they are a very individual and personal thing so I apply whatever is needed to the car after a chat with the client and their proposed use. What different settings do and what to use is easily found on the internet already. This article aims to show you some things maybe you never knew about your NC because they are hidden right under there where I tend to work, we’ll discuss the pitfalls, what to watch out for, why not to bother and the actual mechanics of it.

One of the main attributes of an MX5 is the handling and they did of course handle superbly when they left the factory many years ago. If this is why you bought one you need to know that if it’s your typical ’06 with 100k on the clock it won’t be handling as well as it did due to much of it being worn out. .

The manual states to jack the car up using the diff which rests on just two of these. Good workshop practice? I don’t jack a car up this way. This is also one of the worst ones to get out too.
“Well it had a valid MOT and it handled really well” Hmmm, ok, compared to what, a three legged bar stool? Slackasabagoknackers as we say round these parts.

Anti-roll bar links are known for wearing out and causing a knock or rattle over the bumps, this is also an MOT failure. They are relatively easy and cheap to replace, just be warned you will quite likely have to resort to cutting them off with a grinder or splitting the nut as they just spin round internally when the nut is turned. It is worthwhile putting an allen key in the cleaned out end there and trying it with a spanner first, you never know, miracles do happen sometimes.

The rear bush moves to control castor, front one camber and (age and use dependent) the through bolt is quite often seized in there as you can see.

The bolt head pictured there in a handy recess to hold the water.

What happens is water (sometimes salty of course) sits on the top of the subframe and runs down into the joint where it sits there doing it’s stuff. On a similar note it also gets into the subrames themselves and their mountings, it’s quite common to drop one down and get showered with rusty water or have it running down your arm. The subrame mounting nuts and bolts themselves (exposed as they are) are actually one of the easiest fixings to get off.

Like the front, the through-bolts at the rear are often seized solid to the arm bushes, after bashing them and heating them it’s time to just cut them out.

Thinking of having a go?

You’ll need to be a top level DIYer with access to some decent tools, a good vice and/or press, angry grinder, drills, heat, small chisels and a fair amount of time. The bushes themselves are bonded to the arms so require a combination of drilling, chiselling and even burning out so plan ahead if your car is a daily and get the swear box out, it really is a pig of a job if you’ve never done them before.

I sell and recommend Powerflex for the job, yes they are expensive, but they’re good quality and will tell you how stiff their bushes are, this is known as the ‘Shore rating’. You’ll need the black ones for the suspension. If you’re thinking of using any other brand make note how they don’t give you this important number on the screen so ask for it. What you will find is that some aftermarket bushes are actually more flexible or no better than the ones you are removing, this is because they use a lot of Polyurethane and less metal content than the originals, metal is very stiff right? Of course it is 🙂 Powerflex also use stainless steel for the crush tubes, so seizure is a thing of the past and they are guaranteed for life. We can discuss discounts if you want to purchase a reasonable amount at one time.

Setting the geometry

So many people bang on about their Hunter alignment these days as if the car drove much better because it’s been done by a Hunter and a laser.

How well your car is set up is solely down to the guy doing it not the equipment! That’s a sure fact.

The Hunter is a fantastic piece of kit and the main advantage is its adaptability and speed, the disadvantage is it’s obscene purchase price. An idiot can then mess things up faster and easier if you let him.

WTF, it’s nothing but a piece of string!
Some of the basic tools needed.
Perfect to the millimetre, Mazdas tolerance is to within 4.4.

If you’re simply setting the toe angles to average road settings then generally you don’t have to pull the seized bolts from the bushes. What you will find is because it only needs a little tweak to get it right the now worn rubber bush will twist within itself to allow a setting. I know it’s not 100% correct, but inevitably it is what happens and is just about good enough to keep an old snotter on the road for a bit.

Sand blasted and ready for specialised paint to be applied, the hollow sections are then wax injected. I don’t recommend powder coating, but will maybe discuss this at a later date.
After blasting these were also left to soak in a chemical rust eating solution which we sell before painting.
Don’t forget to paint them a really lurid colour because racecar innit.

Obviously when you’re reassembling everything will be blathered in grease won’t it? Of course it will, shame Mazda never did, but that’s life. If you have a later car and/or one which you intend to hang onto for a while it can be worth your while to pull all these bolts out now, grease them and put them back in, make sure you mark off the alignment on the discs and frame before you attempt anything with a paint mark, dot punch, chisel etc.

So ends another blog, hope you enjoyed or learned something from it, you can leave a comment or questions over there somewhere 🙂

Prices for bushes here: