NC Rear anti roll bar bushes

Technical Area Steering & Suspension
1
  1. My model of MX-5 is: NC 3.5
  2. I’m based near:Sheffield
  3. I’m looking for technical help or recommendations on replacing rear anti roll bar bush. Looks simple enough with rusty fasteners being the only potential problem.
    My question is at 78K miles is the ant roll bar itself likely to be worn?
    Regards,
    Chris
2

Just change the rubber bushes. Soak the bolts in Plus-Gas or similar to ease the job of removing the rusted up bolts.

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3

Thanks Mick

4

Check the drop links at the same time as these are prone to wear as well. If you do change them then there is a 50/50 chance you will have to cut the nuts off. Be careful when tightening the arb bracket nuts they have a tendancy to strip the threads. Recommended torque us quite low. 12 to 14 lbs/ft.

5

Thanks very much, will check the drop links.

6

YES they need changing at zero miles straight out of the factory! :grinning:

7

Hello Stace
You are on his door step, anything MX5 related call Roddisons Motorsport Sheffield
S9 1US
0114 244 5300 ask for Paul.
Regards
Keith

8

why?..

9

I was actually making a bit of a joke BUT as they say “ever a truth said in jest”

personally, when I brought my mark 3.5 (NC2) last September, when it was on 31 thousand I found that the bars on there were about as useful as dental floss!

so I switched to the 30% stiffer and lighter IL Motorsport kit from mx5 parts and found that they greatly improved things!
They firmed the feel of the steering up, they cut the steering wander on hard acceleration, they stopped the car being pulled about by the tram lines that the lorries leave in the tarmac and they also improved cornering entry and exit speeds.

so yes I would advocate replacing with an upgrade. either the IL Motorsport 30% kit (which comes with new rubbers and brackets) or the ones from an RX8

I also suspect that many people who are looking at a shock and spring change might find that once they have fitted stronger bars will find that they don’t actually need to change shocks and springs!
although I’ve yet to hear from anyone that has tried it.

10

Yup, spring stiffness, ride height and anti roll bar torsional stiffness affect how the car shifts weight during cornering. The combined effect of the above influence how much weight shifting (front and back of the vehicle) during cornering and that results to either understeer / oversteer or simply neutral handling.
I expect if you just use the stock suspension you can do a bit of finetuning with the antiroll bars (I was actually planning to do that) but as it has been done numerus times changing the suspension with stiffer springs, a bit of lowering as result of changing the suspension and using the stock antiroll bars and a wheel alignment basically just works.

if the aim is to stop the car rolling, changing the antiroll bars can have undesirable effects. this is why I would be inclined using adjustable antiroll bars.

going back to the original question, I don’t think anyone needs to change the OEM antiroll bar bushes on a stock car if they are not damaged. All they do is to allow the antiroll bar to rotate so IMHO they will have zero performance change on the car.

11

AGREED

12

Thanks very much for all the responses. I’m replacing the bushes as visually the holes are quite elongated and obviously not well.

The springs are stock but shocks proper Bilstein B6s, quite a bit stiffer with excellent body control and improved handling generally. Usual Roddison fast road geometry. Tyres Michelin Pilot Sport 4s front and 5s on the rear

I’m reluctant to change the anti roll bars as the car is often used for long distant holidays and the potential ride deterioration with stiffer anti roll bars outweighs the steering etc. improvements as tbh with the governor onboard 7/10ths is much as I can get away with.

13

I replaced both front and rear arb bushes on mine.
It made no noticable difference to be honest. But it wasnt expensive and at 15 years old it cant hurt anything. Plus makes me feel better that im performing preventive maintenance.

14

Yup , mine are being replaced for the same reason, hence the question about potential bar wear

15

Fair play in regards to the bushes but I personally wouldn’t bother changing the antiroll bars unless they fail. And if they did in your case I’d replace them with the same item.

16

No is the answer.

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17

Cheers

1 Like