BRD Balance Shaft parts required?

[344bigal]

Morning all, getting ready to swap out the balance shaft on my 2006 170bhp BRD engined A4 Avant for the correct KMB replacement kit.
Apart from the obvious oil/filter/sealant etc what other parts should I require?
I know that the subframe bolts are supposedly single use, but are there any other replacement bolts/seals or anything else I should have in hand before I start?

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[Mario]

Going by ElsaWin and the official list of parts Audi say are single use, all of these should be replaced.....

N 90183802 Front Anti-Roll Bar Self locking nuts x4

N 90663002 Bolts for engine console mounts x4

N 90956803 Front sub-frame bolts x4

N 91048802 Vibration Damper Bolts x4

N 10601402 Balance shaft Module to engine bolts x5

N 91123401 Balance shaft Module to engine bolt x1

N 90977502 Balance shaft Module to engine bolt x1

N 91051201 Balance shaft Module to engine bolt x1

N 90951301 Oil Pick-up O-ring seal x1

N 0122942 Oil Pump Follower Key Retaining Clip x1

D 176404A2 - Silicon Sealant for Sump


It's a fair list, however I'm sure you can re-use the ARB nuts and possibly the vibration damper (crank pulley) bolts.

Not so sure about re-using the rest.

I would also recommend changing all the bolts that hold the 2 halves of the balance shaft unit together as they as the same as the ones that hold the unit to the block (in terms of material and torque specs), but I have no idea what length is needed and obviously Audi don't list them as the entire unit is meant to be replaced.

So just be careful when re-using the bolts that connect the 2 halves of the balance shaft unit together and don't over-torque them or you run the risk of snapping.

 

[344bigal]

Now that is a comprehensive list, that's much appreciated!

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[adamss24]

I would not believe half what Etka claims ! Half of them bolts are re-usable and I have done it many a times on cars that ran over 100k since doing work on them !

 

[Mario]

@adamss24 these are all (apart from the nits for the ARB) torque to yield bolts. So they are torqued to a spec near there limit then a further angle to make them physically stretch by fractions of a millimetre.

Best engineering practice is to replace ALL torque to yield bolts. They should not be re-used.

I'm not saying they cannot be re-used, but they SHOULD NOT be re-used, hence ElsaWin says they must be replaced. As once they are stretched, they can snap when being re-torqued.

Once torqued down they're fine, but it's during the tighenting process that re-uses bolts can snap.

It's the exact reason head bolts are not re-used.

 

[adamss24]

I know exactly what are you're saying- I replace the injector hold down bolts and cylinder head bolts however I have rebuilt many an engine yet re-used the old bolts and the cars/engines ran many thousands of miles after ! I don't question the engineering behind it however the world still revolves without us having to throw away everything !

 

[344bigal]

I agree with this, I know and understand why yield bolts should be replaced and whilst I always replace the main ones i.e head bolts, I am guilty of having re-used others that I consider 'less' vital!
In this case I think I'm just going to bite the bullet and replace all of the internal bolts and dependent on the price replace the others as well/later.
Again, many thanks for the list, its a big help!

 

[344bigal]

All done, everything minus the sealant bought the couple of pence short of £78.
Just wondering if anyone knows the spec of the balance shaft connecting bolts so that I can track down some equivalent bolts from elsewhere?

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[Mario]

You mean the bolts to connect the 2 halves together? If so, no-one seems to know the specs of those. However I'm 99% sure they will be identical to one of the balance shaft mounting bolts I listed above. The only problem is we don't know the length.

When you take it apart you can easily measure the length and thread pitch then go and buy some. All the mourning bolts Grade 8.8, I can tell you that much. So it would be reasonable to assume the others will be the same. However you can always check for yourself when you have it in front of you and either pop to B&Q (or similar) for new bolts or go to Audi and order the part number listed above that matches the bolts holding the 2 halves together.

The only problem with going to a normal DIY store to get the bolts is that I think you'll struggle to find ones with the right style of head to sit in the recesses. So it may well be another trip to Audi or re-use them like everyone else does.

 

[344bigal]

Now that's a good idea, unfortunately I'm going to be taking it all apart on a weekend, which of course means only the diy stores will be open, and I don't fancy getting them from there. However I do have a week of coming up between jobs......
Thanks for the help, I'll be compare and buy some new ones methinks.

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[Mario]

@344bigal if you do find out which Audi bolts match the ones holding the 2 halves together can you please post up which part numbers match & the quantities of each?

 

[344bigal]

Of course I can, if it'll help other people out it's not a problem. Hopefully I'll be on it next week some time.

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[344bigal]

Got a week of work, and the replacement shaft and kit should be here tomorrow.
May have it all out then, if not it'll be wed .
I shall post my findings!

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[Mario]

Nice one! I need to get mine done, but waiting for my car ramps to arrive. They were on back order for months, then due to arrive end of April, but my suppliers supplier messed and and sent the wrong ones! Now supposed to be end of June....to say I wasn't happy was an understatement. However I can't blame the guys I am dealing with, they have been good and offered to sort a deal on delivery costs / extras as an apology even though it's not their fault. It's their suppliers who cocked up a massive order and its not just me waiting for these to arrive either. Apparently there are 30-odd people waiting for these to arrive.

 

[344bigal]

Unlucky mate, annoying when things like that happen and it's out of anyone who cares hands!

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[344bigal]

And so it begins....

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[344bigal]

Right, sooooo.
Only just finished and split the balance shaft assembly, due to kids/weather and some extremely stubborn bolts (not the rear sump ones though!).
I'll get a photo up once I've cleaned up, but the 8 out so bolts that hold the assembly together are different lengths than the bolts that hold the assembly to the sump.
So no go on using the part numbers to obtain replacements, there are also no markings on the bolts at all.
So looks like I may have to re-use the old one's.

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[344bigal]

Ok, on the left are the replacement bolts for the shaft assembly to the block.
And on the right are the two different sizes of bolt that hold the two halves of the assembly together.

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[Mario]

Ah well! That's not much good, but suppose you can just re-use them. Everyone else seems to just fine. I know the bolts that hold the unit to the block are grade 8.8 (tiny writing in the heads, difficult to see), so I would expect the ones that hold the 2 halves together to be grade 8.8 also.

I've attached a screenshot of the tightening sequence from ElsaWin for re-attaching the assembly to the block. I would use the same torques for the bolts that hold the 2-halves together, but DO NOT add the extra 90* turn at the end. Personally I would add a dab of blue (medium strength) Loctite just to ensure they don't vibrate loose.

From what I remember, bolts 5 & 7 are lower torque because they are smaller diameter bolts. So use the torque rating that matches the bolts size (M8, M10, etc) that the 2 halves use, if that makes sense?

 

[344bigal]

It was worth a try mate, and I very much appreciate the help.
I'll clean up the bolts and threaded holes and re-torque them with some thread lock if I can find it!
Thanks for the screenshot, that'll come in handy getting it back together tomoro!!

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