Alignment not lasting, caused by worn bushes?

[RJ45]

Alignments don't seem to be lasting; can last 2-3 weeks if I drive like a granny.
But what's the point in having a MX5 if you don't fling it around a corner!
Anyway it's been this way for a while & was hoping new suspension would help, unfortunately not.

My only guess is the original rubber bushes have dried out and aren't absorbing anything.
Is there anything else that should be looked at before I possibly get new bushes all round?

[sailaholic]

Define new suspension? Shocks and springs won't help your static alignment.

How many km and what model? Same shop each time? Any comments from them? Tire shop or suspension shop?

Many pot holes near you?

The rubber fails by splitting and crumbling so is usually visible that failure has happened / happening

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[Dweezle]

Ive heard, take with a grain of salt, that the alignment bolts can often need replacing.
They stretch and lose their holding ability.

[RJ45]

Define new suspension? Shocks and springs won't help your static alignment.

PSS9+FCM shock mount kit installed just a few weeks ago.

How many km and what model? Same shop each time? Any comments from them? Tire shop or suspension shop?

03 NB8B with stock 16" wheels, no mods apart from new suspension, just passed 82,000.
Susp shop, have been sticking with the same one for a while as other places have managed to really stuff it up in the past.

Many pot holes near you?

I'm in Sydney, potholes are everywhere.
Though I do try to steer around them and not go too fast on really rough roads.

The rubber fails by splitting and crumbling so is usually visible that failure has happened / happening

Not getting home before dark these days, so will check on the weekend, Thanks.

[RJ45]

Ive heard, take with a grain of salt, that the alignment bolts can often need replacing.
They stretch and lose their holding ability.

The bolts can't be too expensive to replace.
So will keep it in mind if nothing else pans out, Thanks.

[zossy1]

After that sort of mileage, i'd be surprised if your bushes are shot. The OEM Mazda bushes are actually pretty good. The set I recently pulled out of my 94 Clubman (117K kms) looked like new.

Mark the alignment bolts against the mounts. That way you will be able to see if they are shifting.

If your bolts are shifting, replace them and do them up tighter.

If they're not, then you'll probably need new bushings - surprising, but anything is possible.

[Guran]

Which alignment measure is going out? If it's front toe only, the problem could be that they're not locking off the tie rods tightly. Happened to me a couple times but not since I set the front toe myself.

[jonosx]

Define how they are not lasting.

Who is doing them?

[trader]

Zossy1 did you replace them with OEM bushes? If so did they make any difference?
I've read reports that indicate is is hard to pic the condition visually and that in Tanner's book they recommend change over at 60000 miles. I've done 108000 and the car really bashes and crashes over bumps so will be doing them soon (could be the konis though). Its a big job if not needed though.

[zossy1]

Zossy1 did you replace them with OEM bushes? If so did they make any difference?
I've read reports that indicate is is hard to pic the condition visually and that in Tanner's book they recommend change over at 60000 miles. I've done 108000 and the car really bashes and crashes over bumps so will be doing them soon (could be the konis though). Its a big job if not needed though.

I never drove the car with the old bushes in - I bought it and rebuilt it before driving it (see my build thread).

I replaced them with Energy poly bushes. They get squeaky every now and then but apart from that they are awesome.

I have seen a lot of bushes that are buggered. After 118K kms I expected mine to be RS. It is entirely possible they had been changed before I bought the car but I really doubt it. They had no rubber rot, no deformity, no hardening, no cracking - nothing you would expect to see from bushes on their way. I had a good chance to test them too as I pressed them out in my bearing press. They were in very good order.

Of course, that's not to say yours will be too - depends on a variety of factors. My car had been babied its whole life, garaged, etc.. If your car has been dríven with a bit more spirit, that may have an effect.

[RJ45]

After that sort of mileage, i'd be surprised if your bushes are shot. The OEM Mazda bushes are actually pretty good. The set I recently pulled out of my 94 Clubman (117K kms) looked like new.

Mark the alignment bolts against the mounts. That way you will be able to see if they are shifting.

If your bolts are shifting, replace them and do them up tighter.

If they're not, then you'll probably need new bushings - surprising, but anything is possible.

Yeah, seems to be the common message I get; that it would be a bit of an early demise for bushes, even for a MX5.
But I have been driving on shitty Sydney roads for 4yrs & 50K, with the first half of those K's being a bit more spirited due to the excitement of having a car with handling (was driving a pov pack Falcon for 2yrs b4 that).

Also the original shocks were feeling like they were gone for at least 10K before I put the PSS9's in.

I'm just guessing that; the earlier spirited driving on 3rd world Syd roads helped wear them & driving on worn shocks would have put a lot of pressure on them too. Does that seem about right?

Great suggestion about marking the bolts.
I'll mark them with liquid paper when I look at the bushes this weekend.

[RJ45]

Which alignment measure is going out? If it's front toe only, the problem could be that they're not locking off the tie rods tightly. Happened to me a couple times but not since I set the front toe myself.

I'm not so organised with my paper storage.
So can't find any of the alignment reports.

How do you set your front toe yourself?
What tool(s) are you using to measure that?
Are you using a torque wrench? (What setting?)

[RJ45]

Define how they are not lasting.

Who is doing them?

Right after an alignment steering feels tight/solid and less upset by small bumps & on good flat roads will stay in a straight line very easily if I let go of the wheel.

A few weeks later it starts to feel loose and small bumps set it off quite easy & then even on flat roads it doesn't track so well & I have to hold the wheel a lot more, especially on the crappier roads.
It just gets progressively worse from there until I can't stand it anymore & get another alignment.

And it doesn't feel as tight as it used to after an alignment anymore.

Been using the same place for a few years as they're the only place I found who seem to know what they're doing.
It's Arcus in Artarmon, which used to he a Pedders but dropped the franchise for some reason.
And it is the same guy doing the job each time.

[Guran]

My last couple of paid wheel alignments were done at Pedders. Each time they got a really good alignment that was exactly what I was after. However! First time they didn't lock out the front tie rods at all so the alignment lasted one track day. Second time they didn't tighten the tie rod locking nuts tight enough and the toe went out again after a couple trackdays. Third time, I set the toe myself and it hasn't moved in the last year of severe punishment I have given it on the track all season.

Does your steering wheel look unlevel when the alignment feels wrong? That is a sign of misaligned front toe.

How do you set your front toe yourself?
What tool(s) are you using to measure that?
Are you using a torque wrench? (What setting?)

There are plenty of DIY wheel alignment guides around - just google it or have a look at miata.net to get an illustrated guide. All you need to set front toe is a string line (cotton or fishing line is perfect), a ruler, a set of car stands to tie the string to, and a few spanners. Park on a flat level surface, set up the string line on each side of the car so that they're parallel to and level with the wheel centres. Set the steering wheel straight, then measure the distance between the string line and the wheel rim at the front and back of the wheel. The difference is the toe. To change the front toe, you just back off the locking nut on the front tie rods and twist the tie rod either in or out to suit which way you need to adjust the toe. After adjusting the tie rod on one side, give the steering wheel a good wiggle, reset it to straight ahead and recheck the toe measurement. You'll probably need to repeat a few times to get it just right and then move to the other side. Once it's all good, tighten up the locking nuts on the tie rods. I don't use a torque wrench but the spec is 29-44Nm (3.0-4.5kgf m / 22-33lbf ft). That's equivalent to about 15-22kg of force on a 20cm long spanner, which seems about what I used last time.

[trader]

I've always blamed heavy momo wheels that my car came with as the cause for my bashing and crashing. Just checked weights and they were only slightly heavier than the Mazda 16 inch.