Rear springs

Andrew said:
I came across the same fully threaded rear bottom absorber bolt on mine. I agree it did not seem right for the shock to rest on a thread.

The fun starts trying to buy two, seem expensive and not many sources, one eBay seller wants £15 each!, Audi or TPS will probably be a better bet. If you google the part number some sellers quote the fully threaded bolt as an alternative, no doubt cheaper which is why it has been used.

The manual specifies replace both nut and bolt, personally I would reuse the correct bolt (after all the working force is perpendicular), but I would replace the single use self-locking nut.

Andy
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My local nut and bolt supplier (it's like Screwfix/ToolStation, so a small shop on an industrial estate rather than a huge warehouse like B&Q) has a huge range of nuts and bolts and other fixings. Bright steel high tensile M10 x 75mm long bolts for 18p each, bright steel high tensile M10 nylock nuts for 4p. You measure bolts from the bottom of the head to the end of the thread, not the whole length of the bolt. Of course, they have a huge range of lengths often in 5mm increments in the shorter lengths.

However, I tend to reuse most nuts and bolts. As long as I don't feel the bolt will fail through fatigue I tend to use it again.

If you live near a big town, google "TOWN NAME nuts and bolts". My local supplier was shown on the first page of the google search. However, it is what you might call an industrial town. If your local town doesn't have a lot of industry then you might not find such a good builder's merchant/tool supplier with a huge range of nuts and bolts at low prices.
 
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carlston said:
My local nut and bolt supplier (it's like Screwfix/ToolStation, so a small shop on an industrial estate rather than a huge warehouse like B&Q) has a huge range of nuts and bolts and other fixings. Bright steel high tensile M10 x 75mm long bolts for 18p each, bright steel high tensile M10 nylock nuts for 4p. You measure bolts from the bottom of the head to the end of the thread, not the whole length of the bolt. Of course, they have a huge range of lengths often in 5mm increments in the shorter lengths.
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I'm not sure that I'd want to gamble my suspension on high tensile, bright steel nuts and bolts from a general supplier. Penny wise, pound foolish as they say.
 
steve_c said:
I'm not sure that I'd want to gamble my suspension on high tensile, bright steel nuts and bolts from a general supplier. Penny wise, pound foolish as they say.
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High Tensile steel is what you want. Even your wheel bolts are made from this material.
 
The bolts I took out that were threaded had a tensile strength of 10.9 whereas most of the bolts I see are 8.8, personally I would want to fit 10.9s due to being a safety critical application.
I fitted 8.8s due to being part threaded but had my doubts from the off and have since ordered the correct bolts (according to the part number)
 
A couple of points that have drifted through my head.

I have a memory that these bolts are stretch bolts of which I know little but will these be available at a general supplier?

Although higher tensile bolts will probably be better quality I am struggling to be convinced this is critical as the impulsive force is perpendicular to the bolt.

Andy
 
Andrew said:
A couple of points that have drifted through my head.

I have a memory that these bolts are stretch bolts of which I know little but will these be available at a general supplier?

Although higher tensile bolts will probably be better quality I am struggling to be convinced this is critical as the impulsive force is perpendicular to the bolt.

Andy
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I doubt the bolts holding the rear shocks in place are stretch bolts. However, the bottom bolt on the front MacPherson strut is a stretch bolt...possibly to prevent it failing through fatigue, ie. that bolt needs to be a bit springy.
 
Sheesh, I do wish the group would stop guessing and trying to save money at the wrong end. The bolt part numbers are in the defintive suspension thread list, along with those which are stretch bolts and *must* be replaced. Your original bolt for the bottom of the rear damper is N 905 173 04; the German price for one is currently under €2. The nut is N 102 861 10. 55Nm is the required torque. It's all in the thread and there's a pic here along with a part list PDF (in German).

No point skimping, go to the dealer for this.

- Bret
 
bretti_kivi said:
Sheesh, I do wish the group would stop guessing and trying to save money at the wrong end. The bolt part numbers are in the defintive suspension thread list, along with those which are stretch bolts and *must* be replaced. Your original bolt for the bottom of the rear damper is N 905 173 04; the German price for one is currently under €2. The nut is N 102 861 10. 55Nm is the required torque. It's all in the thread and there's a pic here along with a part list PDF (in German).

No point skimping, go to the dealer for this.

- Bret
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I totally agree but here in uk we seem to get ripped off on most parts compared to the rest of Europe however I did cover this earlier I ordered full bolt kits From Skoda (audi VW) in checz republic a fraction of the price ..
 
The Audi A2 springs are covered by five front springs and three rear springs (not including the Sport models, which I haven't listed).

Five Front Springs

8Z0411105AL (Front springs for 1.4 diesel without panorama sunroof and 1.6 petrol)
Length 338mm, Thickness 11.5mm
Spidan 49515, Suplex 03170

8Z0411105AM (Front springs for 1.4 petrol without panorama sunroof)
Length 330mm, Thickness 11.25mm
Spidan 49527, Suplex 03171

8Z0411105AH (Front springs for 1.4 diesel with panorama sunroof)
Length 338mm, Thickness 11.25mm
Spidan 56830, Suplex 03206

8Z0411105AJ (Front springs for 1.4 petrol with panorama sunroof)
Length 328mm, Thickness 11mm
Spidan 56831, Suplex 03207

8Z0411105B (Front springs for 1.2 diesel)
Length 293mm, Thickness 11mm
Spidan 56832, Suplex 03205

Three Rear Springs

8Z0511115BB (Rear springs for all models with panorama sunroof except 1.2 diesel)
Length 339mm, Thickness 10.25mm
Spidan 56833, Suplex 03208

8Z0511115AS (Rear springs for all models without panorama sunroof except 1.2 diesel)
Length 338mm, Thickness 9.75mm
Spidan 49546, Suplex 03172

8Z0511115AL (Rear springs for 1.2 diesel)
Length 328mm, Thickness 9.25mm
Spidan 56834, Suplex 03209

Alternative Front Spring

An alternative front spring is Audi part number 6Q0411105AC. This spring is listed in the Audi A2 parts catalogue so does fit, and appears to be the same front spring as 8Z0411105AM and 8Z0411105AH except for being 12mm longer than the 8Z0411105AM and 4mm longer than the 8Z0411105AH. It might make a good alternative to 8Z0411105AL as when going down from 11.5mm thickness to 11.25mm thickness the ride height will drop a little if you don't increase the length of the spring. This is because a softer spring compresses more than a harder spring when subjected to the same force.

6Q0411105AC (Alternative front spring)
Length 342mm, Thickness 11.25mm
Spidan 85703, Suplex 39205

Sources of Information

gknautomotive.com
optimal-germany.com
autodoc.co.uk
 
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Andrew said:
A couple of points that have drifted through my head.

I have a memory that these bolts are stretch bolts of which I know little but will these be available at a general supplier?

Andy
Click to expand...

Think I know a little bit more (but not a lot) about stretch bolts

Critical bolted joints usually need to meet a designed clamping force. Applying a set Torque to bolts often gives varying results, mainly depending on the 'tightness' and condition of the thread form. Dry, lubricated, rusty, dinged, high or low thread form tolerances are all thread variables which can affect the clamping load.
Moving from torque only to torque plus angle allows the bolt to be taken precisely through the elastic and into the 'plastic' limit of the material to achieve that designed clamping load.
The initial torque snugs the bolt then the angle stretches it, usually to the point where it literally starts to neck and deform the shank. Often when applying the angle you can feel the bolt give at this point.
Confession time. In my early Audi days (90 Quattro 20v) I replaced lower wishbone bolts 3 times thinking I'd overdone the angle setting and ruined the bolts.

Anyhoo (word stolen from Murdo) that's the reason you can't re-use stretch bolts

Cheers Spike
 
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