The curious case of the Atom 4 brakes

[Curves Junkie]

It may be worth bearing in mind that Alcon calipers fitted to some of the earlier Atoms all had springs fitted from the outset.

My Atom 3 from 2010 have no springs - neither front nor rear. No springs in the housing of the caliper to press the pistons against the brake disc. Only a 4 edge sealing ring and the piston - nothing else.

IMG_6190.JPG

So no springs and your ones have dust seals!!

No, not correct - this are no dust seal seals.
The Alcon calipers front and rear have no dust seals.
The sealing rings that you see in my post above, are for sealing, so that the brake fluid does not leak out and because these sealing rings have a square shape, they minimally (<1mm) pull the piston back from the brake disc.

Dust seals will have only the handbrake calipers.
Look at the picture in the upper left corner

IMG_5879.JPG (3.4 MiB) Viewed 1646 times

Could it be that a different caliper was used on the 3.5 cars?

No, AA3 and AA3.5 used the same Alcon brake calipers.

[robfitz]

Stu - did you get yours fitted at the factory?

[wasp]

Stu - did you get yours fitted at the factory?

Yes, it was the first set they had done. I think that they were interested to see how the springs went particularly.

Cheers,
Stu

[plip1953]

My Atom 3 from 2010 have no springs - neither front nor rear. No springs in the housing of the caliper to press the pistons against the brake disc. Only a 4 edge sealing ring and the piston - nothing else.

IMG_6190.JPG

So no springs and your ones have dust seals!!

No, not correct - this are no dust seal seals.
The Alcon calipers front and rear have no dust seals.
The sealing rings that you see in my post above, are for sealing, so that the brake fluid does not leak out and because these sealing rings have a square shape, they minimally (<1mm) pull the piston back from the brake disc.

Dust seals will have only the handbrake calipers.
Look at the picture in the upper left corner
IMG_5879.JPG

Could it be that a different caliper was used on the 3.5 cars?

No, AA3 and AA3.5 used the same Alcon brake calipers.

Isn't that a form of dust seal - see annotated pic.

[PhilM]

It sounds like people who have changed the master cylinder sizes, fitted anti knockback springs and the pedal box brace have felt a significant improvement in the brakes, but has anyone just fitted the springs or done it step by step, to see what difference each change makes?

[reg]

Stu - did you get yours fitted at the factory?

Yes, it was the first set they had done. I think that they were interested to see how the springs went particularly.

Cheers,
Stu

Look forward to the refund

[plip1953]

It sounds like people who have changed the master cylinder sizes, fitted anti knockback springs and the pedal box brace have felt a significant improvement in the brakes, but has anyone just fitted the springs or done it step by step, to see what difference each change makes?

We went one step at a time, but not necessarily in the ideal order. Nevertheless we noticed improvements in pedal travel (ie reduced) at ever step.

I think I said this in an earlier post, but would definitely recommend the pedalbox brace and then next would be to fit the anti-knockback springs. I still don't fully understand why fitting the springs seems to work, but seemingly it does.

[Yorkshire]

Looking forward to somebody just fitting knock back springs alone to see the difference

[Curves Junkie]

Isn't that a form of dust seal - see annotated pic.

NO, it is not a dust seal

[reg]

Makes sense to me after the factory described their magical bleeding procedure. TBH. We can all dance around it, but as owners, spending hard earned money, we’ve been taken advantage of. Despite numerous pleas for help it is clear that the factory doesn’t actually give a sh1t about their customers and are more than happy to let them solve issues which they are wholly responsible for.

[plip1953]

Isn't that a form of dust seal - see annotated pic.

NO, it is not a dust seal

Then what is it? A secondary piston seal that does what?

[Curves Junkie]

Isn't that a form of dust seal - see annotated pic.

NO, it is not a dust seal

Then what is it? A secondary piston seal that does what?

Your attachment shows another Alcon brake caliper as we have at our Atoms.
Our caliper have only one seal ring per piston and not two seal rings. And this one seal ring does this job as I wrote you in a early post.

[HenryJS]

OK,

Its probably time i jump in here - as I feel this is starting to get out of hand.

I have spoken with most of the people in this thread about their brakes and have offered to them that we have their car back here, inspect it and remedy the issue they are having. Some have taken us up on it, some haven't. We have many different reports from many different people about the brakes.

We are (and have been) looking into why there are a few people with this issue (which in it self seems to be a varied problem) and we MUST take a measured approach... WHY is the issue occurring. WHAT is making the issue. WHICH part needs attention. HOW we can remedy it.
We cannot 'fire up the parts cannon' and fit different pads, knock-back springs, a different master cylinder, a bracing part and a different bleed procedure. As yes it may remedy the issue - but which part fixes it? We MUST have scientific answer.
Its akin to setting up your car for a track, if you change Camber, Toe, Tyre Pressure and Damper set up and it gets worse - you have NO chance of finding out why.

We have not been able to replicate the issue with our demo vehicle so it is of the utmost importance that we tackle these issues with the vehicles that are affected. So far i believe we have fitted two sets of knock back springs for customers at their request and have had positive initial feedback. This needs to be followed up and we are doing so.

As I'm sure you are all aware, we extensively tested the car and arrived at the parts we fitted for a reason, not because we just chucked any old stuff on it. So we need to do the same thing again... Test and tune. Then we can give a calculated answer with a reliable solution.

If any one wants to discuss their vehicle, please contact me at Ariel.

[plip1953]

We have not been able to replicate the issue with our demo vehicle so it is of the utmost importance that we tackle these issues with the vehicles that are affected. So far i believe we have fitted two sets of knock back springs for customers at their request and have had positive initial feedback. This needs to be followed up and we are doing so.

Are you saying that your demo car doesn't have any kind of issue? If so, that's really interesting in its own right, and I would have to agree that it makes it doubly difficult to find scientifically robust solutions to problems when only being experienced by some others.

[robfitz]

Doh - springs now on back order….