Nct side slip /alignment test

cojomo2

Hi,

Bringing the car for NCT soon. Looking at the old test sheet from 2 years ago, it nearly failed the side slip/alignment test for the rear axle. The result was -18m/km which is right on the limit.

I'm guessing its fair to assume it will fail this time given 2 yrs have passed so I'd like to sort it before bringing it in for the test.

The car is a 07 daihatsu sirion..anyone know if its a simple case of getting the tracking done, or is that only for front wheels? Or is 4 wheel alignment the same thing?

If not, then do the bushings need replacing? thanks

Chimaera

Failure on the side slip test is most likely worn suspension parts. I'd get it looked over by a competent mechanic before the test. If it's a '07 on its original parts, there's a good chance they've worn down enough to be in need of replacement.

greasepalm

dont expect to get parts handy,3 days waiting on price of mirror cover and want paying first before ordering and told 7 day +

If suspension bits were worn enough to have that result on slide slip I would expect a fail on a component. They are checked for play.

Semi ind suspension on the back of a sirion, easy to spot wear.

cojomo2

Augeo wrote: »

If suspension bits were worn enough to have that result on slide slip I would expect a fail on a component. They are checked for play.

Semi ind suspension on the back of a sirion, easy to spot wear.

Would getting 4 wheel alignment done possibly sort it?

visual

cojomo2 wrote: »

Would getting 4 wheel alignment done possibly sort it?

Your will need alignment after replacing suspension parts. Waste of money before

cojomo2

visual wrote: »

Your will need alignment after replacing suspension parts. Waste of money before

Can alignment not go off over time from potholes etc ?

visual

cojomo2 wrote: »

Can alignment not go off over time from potholes etc ?

Thats as useful as a apple a day keeps doctor away.

Potholes and bad roads damage or prematurely wear suspension parts like bushes ball joints
it can cause the angle the wheel meets the road to change. Resulting in wheel being misaligned.

Adjusting the alignment isnt fixing the fault at best its hiding it.

Tyre shops rarely check the suspension parts unless it very obvious fault that stops them adjusting the toe or camber of wheel.

This results in the following
wheel alignment is off due to a faultly part causing the wheel to be at a odd angle. Tyre shop ignores the real reason as pothole sounds good and easy for customers to understand and accept plus they get paid for doing alignment.

awhile later the faulty part wears a bit more alignment off again and tyres wear unusual.
Another alignment and more stories of shocking roads and potholes.

The fault still not fixed only to return again or fail at next NCT eventually turns out that a ball joint, broken spring or worn wishbone / control arm or bushing is replaced and final alignment is completed fixing the fault.

Dont accept the BS story potholes knock alignment off. If you think about it alignment is undoing a lock nut and adjusting the toe / camber. If the wheel changes toe or camber something other than the adjustment nut has changed.

If you align wheels with worn damaged suspension parts then after you repair the fault you have to realign the wheel again.

cojomo2

Just following up on my original post as put the car throught the NCT today. Am I correct in that if the rear axle side slip test result was -18m/km 2 years ago , today's result should have been a fail (outside the allowable limit of +18 to -18 m/km?)

Oral Surgeon

cojomo2 wrote: »

Just following up on my original post as put the car throught the NCT today. Am I correct in that if the rear axle side slip test result was -18m/km 2 years ago , today's result should have been a fail (outside the allowable limit of +18 to -18 m/km?)

??? Are you correct?? You should have the result of the Nct today??!!! Why are you asking us??

George Dalton

cojomo2 wrote: »

Am I correct in that if the rear axle side slip test result was -18m/km 2 years ago , today's result should have been a fail (outside the allowable limit of +18 to -18 m/km?)

Why would you think this?

mgbgt1978

cojomo2 wrote: »

Just following up on my original post as put the car throught the NCT today. Am I correct in that if the rear axle side slip test result was -18m/km 2 years ago , today's result should have been a fail (outside the allowable limit of +18 to -18 m/km?)

No you are not correct in saying that.
The original side slip 'imbalance' could have simply been as a result of your rear suspension components taking a knock. A few potholes later and things were (slightly) bent back closer to the limits.
Or, it could just be the different readings from 2 different machines at your NCT Test Centre .

cojomo2

George Dalton wrote: »

Why would you think this?

I don't fully understand the result - but I expected that I would fail today givin that I was rite on the limit on the last test 2 yrs ago. I expected that with 2 yrs wear and tear the original reading of -18m/km would increase to at least -19m/km resulting in a fail?

pablo128

cojomo2 wrote: »

I don't fully understand the result - but I expected that I would fail today givin that I was rite on the limit on the last test 2 yrs ago. I expected that with 2 yrs wear and tear the original reading of -18m/km would increase to at least -19m/km resulting in a fail?

What is the reading now?

George Dalton

cojomo2 wrote: »

I don't fully understand the result - but I expected that I would fail today givin that I was rite on the limit on the last test 2 yrs ago. I expected that with 2 yrs wear and tear the original reading of -18m/km would increase to at least -19m/km resulting in a fail?

No it's not as simple as that. The side slip reading can be affected by lots of factors so the result of another two years of wear and tear isn't predictable.

cojomo2

mgbgt1978 wrote: »

Or, it could just be the different readings from 2 different machines at your NCT Test Centre .

That's exaclt what I thought. Both tests were in different centres ..today's result was -6m/km..thought it was strange as nothing has been done with the car since the first test bar oil and filter services. Obviously not complaining, delighted but was just curious about the result.

mgbgt1978

Tbh it's far from unusual.
My shocks (on various cars) seem to improve and deteriorate (on opposing sides ?) over the years ????
Same with Brake Imbalances ????
And Brake Ovality seems to jump from one side to the other ???
Also many of my cars have gone on a diet and lost up to 150kg (with the same amount of fuel) after less than 12 months.....sometimes they gain massive amounts of weight.
But I'm sure the NCT's Equipment is totally reliable and checked regularly so it must be my fault somehow .

lomb

Changed the front wishbones on a golf with Delphi parts and the steering wheel is off centre a bit but drove reasonably straight. Thought put it through anyway. Passed with-9 and -5. Something still wrong though imp and needs tracking/front camber adjustment.
My Tt failed at something like -20 3 years ago on the rear but you could see one wheel pointing completely out toe and massive rear camber. Some adjustable lower tie bars sorted it perfectly. If you had -18 somethingu was seriously wrong .Id say nct equipment must be calibrated regularly.