Questions about a full suspension refresh

Technical Area Steering & Suspension
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  1. My model of MX-5 is: NC3.5
  2. I’m based near: Bristol
  3. I’m looking for technical help or recommendations on: Replacing suspension components.

Hi all

Now that the mx5 parts container has finally arrived, I’ve now had delivered a set of 4 OEM dampers, springs, top mounts and gaiters.

I’ve also purchased a full set of polybushes to replace all suspension bushes (street hardness rather than racing), including those for the ARBs and the diff.

Before I get started on the work, I want to do as much preparation as possible.

Please can I have some advice on the following:

Alignment bolts. My alignment specialist reported a seized castor bolt. This didn’t have much impact on the fast road set up that he does, however he did quickly apply some heat to the bolt but it wasn’t playing ball and he opted to leave it rather than risk snapping it.

I’ll obviously need to address this. I’m planning to buy some replacement alignment bolts and get a lot of heat on it if a couple of weeks worth of penetrating fluid doesn’t free it.

Does anyone have some suggestions on how I could go about this?

Also, I’m planning to mark the position of the alignment bolts as best I can, so I can change the suspension and bushes and then do one visit for an alignment afterwards. Is this the best way forward?

This suspension change is a big job for me, and I’m really looking forward to contorting myself under the car for hours :slight_smile:

Any comments welcome.

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You could invest in some equipment Buy ADA Castor Camber Gauge - CG | Demon Tweeks (demon-tweeks.com) and Buy Trackace Laser Wheel Alignment Gauge - TAG01 | Demon Tweeks (demon-tweeks.com)and measure what you have and then replicate it after the fitting of your new bushes.
It could be that it would pay for itself throughout your life time.
:heart:

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Expect the worse with the alignment bolt, it’ll fight you all the way. Be prepared for the fact that you might have to resort to cutting it.

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Some of my own adventures are here:

I did mark the bolt positions but I don’t know if that helped, I drove it slowly and directly to FCM to get aligned.

The caster bolt requires cutting if seized.

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Thanks for your replies, everyone. To cover a worst case scenario I’ve just ordered 2 replacement caster bolts.

@stevegilkes what were the most common drill bit sizes you were using when drilling out the old bushes?

Also, can anyone recommend a budget blowtorch that can be used at any angle?

Finally, if known, please can someone advise on the size of the damper piston rod end nuts for the front and rear dampers? The rear dampers came wit
hout them, and the front dampers came with one present, but the other box was opened and then taped shut. When I opened it the top nut was missing.

Many thanks

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I used c.5mm drills to make holes to allow the jigsaw to make a start.

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If you’re buying new alignment bolts get them from MX5 parts. I have a NC3.5 and recently replaced the front lower wishbone bushes and some of the bolts were seized. At the time they were out of stock with MX5 Parts but I decided to wait as to buy these items from my local Mazda dealership they were going to be almost twice as expensive.
Dave

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The front lower bolts, which I understand are for castor adjustment, were indeed out of stock and I impulsively ordered a set last night that were in stock for £45! I was tired and should have waited :sob:

It’s wishful thinking but seeing as my last alignment was only 6 months ago and the only reported seized bolt was one for castor adjustment, I’m hoping the other adjustment bolts are cooperative.

Thanks again everyone for contributing to this thread, I’ll be starting work once I’ve gathered everything I think I’ll need and I’ll update the thread.

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Here is an alternative adjuster bolt I found recently in case I needed any replacements :+1:

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By the way, I am also in Bristol if you need help.

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@stevegilkes thanks for your kind offer, I might end up taking you up on this if I get in a pickle!

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Just a quick update on the prep for this job.

Damper top nuts: If anyone wondered the answer when I queried the size, they’re M10 with 1.25 pitch.

I’ve added the following to my tool kit:

Threaded rod with nuts and washers

A set of 3 pullers

Can of PB Blaster

Decent vice off eBay fitted to work bench

Just a few other jobs to finish off and then I can get started.

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When I did my nissan on some of the bushes the steel liners wouldnt come out. This necessitated burning or cutting the rubber out and using a hacksaw to cut through the liner only so it could be drifted out.

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@Dean_S550 Thanks for sharing your experience. I anticipate having to do the same thing on the wishbone bushes.