NCT failed 2nd time suspension

1123heavy

Previous failure had 3 issues, one was straight forward (parking brake), the other 2 concerned the suspension of the vehicle.

I was told to change the front offside ball joint and nearside rear coil spring.

I changed both of them and took it in this morning, it failed again, this time on front axle imbalance, he told me I needed to change my front shock absorbers.

First Test Readings:

Front axle: 33Mm 32Mm .. imbalance 3%
Rear axle: 45Mm 36Mm .. imbalance 20%

Second Test Readings:

Front Axle: 36Mm 24Mm .. imbalance 33%
Rear Axle 34Mm 32Mm .. imbalance 9%


Front axle imbalance has increased by 30%, surely it can't be the shock absorbers? Do I really need to change them or is the imbalance being caused by the fact I only changed the rear nearside coil spring without the rear offside too?

Any opinions/observations much appreciated

BlakeS94

1123heavy wrote: »

Previous failure had 3 issues, one was straight forward (parking brake), the other 2 concerned the suspension of the vehicle.

I was told to change the front offside ball joint and nearside rear coil spring.

I changed both of them and took it in this morning, it failed again, this time on front axle imbalance, he told me I needed to change my front shock absorbers.

First Test Readings:

Front axle: 33Mm 32Mm .. imbalance 3%
Rear axle: 45Mm 36Mm .. imbalance 20%

Second Test Readings:

Front Axle: 36Mm 24Mm .. imbalance 33%
Rear Axle 34Mm 32Mm .. imbalance 9%


Front axle imbalance has increased by 30%, surely it can't be the shock absorbers? Do I really need to change them or is the imbalance being caused by the fact I only changed the rear nearside coil spring without the rear offside too?

Any opinions/observations much appreciated

The readings say the imbalance is on the offside I.e drivers side front. You had offside ball joint changed? Maybe investigate the work done or if you DIY'd it double check everything that you may have removed to access the ball joint.

1123heavy

BlakeS94 wrote: »

The readings say the imbalance is on the offside I.e drivers side front. You had offside ball joint changed? Maybe investigate the work done or if you DIY'd it double check everything that you may have removed to access the ball joint.

I wasn't aware the ball joint would affect the balance, I thought it'd be more to do with the springs. I got it done at a garage not DIY, I might go elsewhere this time to get the work checked so.

BlakeS94

1123heavy wrote: »

I wasn't aware the ball joint would affect the balance, I thought it'd be more to do with the springs. I got it done at a garage not DIY, I might go elsewhere this time to get the work checked so.

To my knowledge it can't, faulty ball joints would more affect tracking and steering. But they connect to control arms which connect to the cars chassis so maybe in extreme cases. But I believe its primarily the likes of springs and shocks that affect axle imbalance. What I'm suggesting is you dont know what the garage removed to access the ball joint, some can be tricky they could have ugga dugga'd a few components with an impact to remove them for better access. To be honest I'm unsure I'm just providing fresh eyes on the situation. I've seen people knock out the Axle shaft and take off the steering knuckle altogether to remove the ball joint.

kermitpwee

BlakeS94 wrote: »

To my knowledge it can't, faulty ball joints would more affect tracking and steering. But they connect to control arms which connect to the cars chassis so maybe in extreme cases. But I believe its primarily the likes of springs and shocks that affect axle imbalance. What I'm suggesting is you dont know what the garage removed to access the ball joint, some can be tricky they could have ugga dugga'd a few components with an impact to remove them for better access. To be honest I'm unsure I'm just providing fresh eyes on the situation. I've seen people knock out the Axle shaft and take off the steering knuckle altogether to remove the ball joint.

What car did you see that procedure done on?

BlakeS94

kermitpwee wrote: »

What car did you see that procedure done on?

A Honda CRV, didn't physically stand there and see it but watched it on a YouTube vid when I was trying to figure out how to change them myself

1123heavy

I'm finding mechanics aren't interested in just checking the ball joints were placed properly etc .. everyone I'm speaking to says just change the shock absorbers, I just find it so bizarre that in the space of a week my shock observers have somehow given in or not fit for purpose. After previously having an imbalance of only 3%

BlakeS94

1123heavy wrote: »

I'm finding mechanics aren't interested in just checking the ball joints were placed properly etc .. everyone I'm speaking to says just change the shock absorbers, I just find it so bizarre that in the space of a week my shock observers have somehow given in or not fit for purpose. After previously having an imbalance of only 3%

Measure the distance between the top of tyre and the centre of the wheel arch above it on both sides and see if there's a very different number. Also, just ask for a pre nct check? Most garages will oblige, mention nothing about the fail or previous test

1123heavy

Well I've an update.

I spoke to a mechanic who said I should have insisted on the spot they try a different lane and advised me to go back to them. I did just that and went back to the NCT centre with the 2 retest forms and challenged the 33% front axle imbalance reading.

After much ado and lots of insisting and negotiating my way with the inspector, he gave in and accepted to retest the car in a different lane there and then.

It passed!

Front axle imbalance 30% (3% drop)
Rear axle imbalance 3% (6% drop)


Right on the line but who cares, goes to show, I hadn't touched the car in the 24hrs since the fail!

kadman

So what was the inspectors reasoning for it passing in a different lane.
Or did he offer any?

1123heavy

kadman wrote: »

So what was the inspectors reasoning for it passing in a different lane.
Or did he offer any?

None, in fact he tried to justify the initial retest reading by saying it was only an additional 3% in the other lane and basically I passed on luck, not due to a bad reading and that the car is still imbalanced.

But they both dropped, why not increased? There are still people heading into the lane I was in 2 days ago and being told their vehicles have failed when if they were in another lane they'd have passed! It's ridiculous. I lost 2 days working from home with this nonsense now have to work my weekend to catch up.

BlakeS94

1123heavy wrote: »

None, in fact he tried to justify the initial retest reading by saying it was only an additional 3% in the other lane and basically I passed on luck, not due to a bad reading and that the car is still imbalanced.

But they both dropped, why not increased? There are still people heading into the lane I was in 2 days ago and being told their vehicles have failed when if they were in another lane they'd have passed! It's ridiculous. I lost 2 days working from home with this nonsense now have to work my weekend to catch up.

I wonder how regulated the NCT is and how often if at all the testing components are checked for accurate readings?

smuggler.ie

Few months back NCT'ed my Passat - failed on trailer lights -> no power on socket. €28 retest fee as "it require tool to test"

Insisted on immediate retest that was done after little argument with supervisor: "it was two separate test done, both failed" - i knew all was in 100% order as had towed trailer that same day.
Test tool broad out, certificate and apologies issued on the spot. This all was outside, 20 witnesses watching supervisor walking away with "tail between legs" .

1123heavy

smuggler.ie wrote: »

Few months back NCT'ed my Passat - failed on trailer lights -> no power on socket. €28 retest fee as "it require tool to test"

Insisted on immediate retest that was done after little argument with supervisor: "it was two separate test done, both failed" - i knew all was in 100% order as had towed trailer that same day.
Test tool broad out, certificate and apologies issued on the spot. This all was outside, 20 witnesses watching supervisor walking away with "tail between legs" .

It seems to be the minions cannot think outside the box. Common sense doesn't seem to be the order of the day. Thankfully the inspectors, when called up, do seem to be a bit more reasonable.

1123heavy

Regarding regulation, i dont know, i dont think the status quo has ever been questioned. Any regulation seems to be very loose and we pay the price of that.

Speedline

By putting a new rear spring in, the height was raised on that corner. That is going to affect the front as well. The front suspension may well be out of alignment now.

And a 3% difference between 2 ramps that see thousands of cars a year? I'd call that pretty good going to be fair.

1123heavy

Speedline wrote: »

By putting a new rear spring in, the height was raised on that corner. That is going to affect the front as well. The front suspension may well be out of alignment now.

And a 3% difference between 2 ramps that see thousands of cars a year? I'd call that pretty good going to be fair.

That was what I originally thought too, the mechanics I spoke to disagreed though. The inspector at the NCT didn't say anything about the rear spring I changed being connected either. In actual fact he said if it was only the rear axle I had to touch they would not have checked the frontaxle at all. It was because I changed the front ball joint they rechecked it.

Working in aviation I work with some machines that must deliver pin point accuracy everytime so it doesn't impress me actually. Do they have the same motivation to be as accurate? Considering their errors must be paid for by the consumer who often is none the wiser as to them 'failing' being no fault of their own - I'd expect better. The previous poster gave another example of where machinery wasn't even relevant, it was the employee.