NCT fail on Tracking/Slip just hours after getting tracking done

Malpaisian

My car failed the NCT a couple of weeks ago at the Deansgrange centre. It failed on the front wishbone bushes. The guy at the NCT told me that the tracking (wheel alignment) has to be done after these are replaced so, when it came to retesting, the tracking/slip test would have to be redone.

I brought the car to Firststop in Donnybrook to have the wishbone bushes replaced and the tracking done. They produced a data sheet saying that the wheels were aligned within tolerance for the nct. A few hours later, the car failed on the Tracking, this time in the Drogheda centre.

I brought the car back to Firststop. They insisted that their system is more accurate than the the one used by the NCT. They hooked the wheels up to all of their gizmos again and produced a data sheet showing that the tracking was within NCT tolerance. They also gave me a photocopy of their certificate of calibration. That was last Friday. I brought the car back to Deansgrange today and it failed on the tracking again. This time they brought me in and showed me the slip test being done.

Has anyone any ideas?

Chimaera

The two tests are not directly comparable. The alignment check done by the garage checks that each wheel is at a particular angle to the vertical and horizontal as the car sits on the ground. It won't necessarily show if the wheels are out of position relative to each other, nor any misalignment that arises as the wheels move through the suspension travel.

The NCT slip test measures how much the car is likely to drift to the side over a set distance and can be affected by things the alignment check isn't able to measure such as might be caused by chassis misalignment, etc.

So Firststop can't promise you that their system will guarantee a pass in the NCT IMO.

What make/model of car are we talking about?

Doom

Visit another garage, ask for a photocopy and compare, if it is out in new garage, go back to firststop and demand money back.

CiniO

Malpaisian wrote: »

My car failed the NCT a couple of weeks ago at the Deansgrange centre. It failed on the front wishbone bushes. The guy at the NCT told me that the tracking (wheel alignment) has to be done after these are replaced so, when it came to retesting, the tracking/slip test would have to be redone.

I brought the car to Firststop in Donnybrook to have the wishbone bushes replaced and the tracking done. They produced a data sheet saying that the wheels were aligned within tolerance for the nct. A few hours later, the car failed on the Tracking, this time in the Drogheda centre.

I brought the car back to Firststop. They insisted that their system is more accurate than the the one used by the NCT. They hooked the wheels up to all of their gizmos again and produced a data sheet showing that the tracking was within NCT tolerance. They also gave me a photocopy of their certificate of calibration. That was last Friday. I brought the car back to Deansgrange today and it failed on the tracking again. This time they brought me in and showed me the slip test being done.

Has anyone any ideas?

I would love to see that wheel alignment data sheet confirming that tracking is done within NCT tolerance.

slimjimmc

Two different test centres producing a fail would make me query the tyre centre's readings. Did the NCT tests give similar results. Likewise do the tyre centre's 2nd readings match their 1st.
Personally I'd get the alignment checked in another place. If the second place passes the NCT I'd go back to Firststop for a refund.

CiniO

slimjimmc wrote: »

Two different test centres producing a fail would make me query the tyre centre's readings. Did the NCT tests give similar results. Likewise do the tyre centre's 2nd readings match their 1st.
Personally I'd get the alignment checked in another place. If the second place are consistent with NCT 's I'd go back to Firststop for a refund.

But NCT doesn't check wheel alignment and as so doesn't give any results which could be comparable to reading from tyre centre on wheel alignment.

Tails142

I didn't think you could get a retest done in a different test centre.

Malpaisian

Chimaera wrote: »

What make/model of car are we talking about?

It's a Seat Toledo 2006

dr.fuzzenstein

Tails142 wrote: »

I didn't think you could get a retest done in a different test centre.

Yes, no problem.
Failed my NCT in Charleville and did the retest in Ennis.
I'm not sure about the retest of a retest.
Different test center, fiddy in the ashtray, sorted.

dr.fuzzenstein

CiniO wrote: »

But NCT doesn't check wheel alignment and as so doesn't give any results which could be comparable to reading from tyre centre on wheel alignment.

So that means they are testing something that is not readable/adjustable by any garage?
How is one to fix this then?
How is a slip test not related to the wheel alignment?
I'm genuinely curious, because is this something that only the NCT can measure and we can only guess at?

Malpaisian

I forgot to mention that about 10 days before Firststop got to it, my car actually passed the Slip Test but failed on the bushes. The NCT Report shows the tracking well within tolerance. It's only since they replaced the bushes that the car can't pass the slip test.

joujoujou

dr.fuzzenstein wrote: »

[...]
How is a slip test not related to the wheel alignment?
[...]

Sticky caliper or faulty wheel bearing can also give side slip.

Malpaisian

dr.fuzzenstein wrote: »

So that means they are testing something that is not readable/adjustable by any garage?
How is one to fix this then?
How is a slip test not related to the wheel alignment?
I'm genuinely curious, because is this something that only the NCT can measure and we can only guess at?

My thoughts exactly.

Malpaisian

joujoujou wrote: »

Sticky caliper or faulty wheel bearing can also give side slip.

Would these not show up in the NCT? I asked the guy today if there is any possibility that there is something worn or broken which has not been picked up upon by the NCT and may be causing the slip-test failure. He said "no".

mickdw

I dont know how the nct test this but im guessing if you had a car with severely worn suspension bushes etc, you could get the alignment set with the car sitting stationary on all four wheels. You could still find that driving down the road it could be mad out of line when acceleration / braking forces are applied.

In short, its likely the car has wear in the suspension and is producing different readings in the different test situations.

Of course, its also possible that the alignment guy is a monkey.
I would get it checked in another centre and also check was worn components.

joujoujou

Malpaisian wrote: »

Would these not show up in the NCT? [...]

Well, in theory, yes.

My answer was just to show that not only alignment is slip related.