Worn oil pump hex drive shaft on MY09 2.0 TDI

[hollows wife]

did this balancer shaft / drive swap to my old 09 plate a4 3 years ago . i went and collected the kit direct from kmb ,at that time it cost me £150 exchange .
most of the 170 engines have the balancer shaft setup .
the parts from KMB Parts Direct are far far better than audi's own design. the shaft fits the new balancer shaft so good that it causes a suction when trying to remove it .
i would recommend to anyone to go to these for a replacement part rather than audi even if the parts were the same price .

 

[Audiforlife]

Thanks for the reply hollow.. it is something I will go for in the near future! Are there any special tools needed for the job? For now I am just wanting to take the key shaft out and inspect it and maybe fit the 100mm. Have recently fitted a replacement engine which apparently has only 29k on it. Once I've removed the sump and the circlip off the pump cassette, what would be the best way to slide the hex key out for inspection?

 

[Gazwould]

Always the repeated misconceptions.

1. You can't fit a new 100 mm key if you have 77 mm.

2. Fitting just a new key is a waste of time, money and is pointless as this is primarily a balancer shaft #2 keyway bore poor design issue .

 

[Audiforlife]

I was waiting for number 2 off you Gaz lol
Like I said I have replaced the engine and am doing a service before the 1st start up. I have read all the threads including the 38 page one.
Once the car is up and running and I decide to keep the car I will be replacing both.

Thanks for point number 1 though, guess if I take it out and it is worn I will just get the 7mm solid shaft for now!

Any pointers on easiest way to extract the shaft?

 

[Audiforlife]

Right engines up and running, I'm going to order the kmb shaft and drive. Is there a guide on how to replace it?

Thanks in advance

 

[Gazwould]

Disconnect battery negative lead.
Slacken OSF wheel nuts.
Jack up car slightly to remove undershield and remove wheel and wheel arch liner.
Slacken auxiliary belt tensioner and lock off with suitable "pin" (allen key, drill bit or short handled screwdriver) and remove auxiliary belt noting its rotational direction.

Remove timing belt covers and crank pulley.
Drain oil.
Jack up higher and support with axle stands at suitable points to the rear of the subframe to allow room to work under engine.
Disconnect oil level sensor plug, remove sump, remove leftover silicone sealant from sump edge and crank carrier surfaces as you will need to reseal the sump for refitting - their is no sump gasket.

At this point you will see the balancer shaft unit bolted below the crank.
Lock cams and toothed crankshaft cog at TDC with appropriate locking tools.
This also locks the balancer drive cog on the back of the crank gear cog inside the sump area.
Support balancer unit and undo the 8 retaining bolts, if I remember rightly one of these is a long oil pump bolt and they are different sizes so use a piece of cardboard and pop them in the same positions on the cardboard noting that you are looking upwards at the balancer unit (renewal of the bolts is recommended as they are stretch type with additional angle stage tightening).
Wiggle the unit slightly and it should come away - it is HEAVY!!
Lower it carefully, it still has a lot of oil inside and remove from under the car.

Remove circlip from oil pump drive key hole (it's very small - renew it).
Drive key can be removed with a small magnet or by feeding it through from the balance shaft end.
Balancer unit is in two halves. Remove strainer pipe checking gauze is clear (clean pipe and gauze if necessary and renew pipe seal).
Undo retaining bolts again they may be different sizes and lift off top half leaving bottom half with balancer shafts in situ.
Shafts can be lifted out from bottom half of unit and gearing checked.
Replacement is usually no 2 shaft which has the drive key hole for the pump with a modified version (yours or exchange).
Clean visible oil channels on both halves and inspect shell bearings of balancer unit where shafts sit. Renew shells if worn or scored.

Apply thick oil or assembly lube to inside of shells and clean balance shaft journals.
When replacing a shaft ensure that the flat surface of the balance weight on each shaft sit level with each other (once their gear cogs have been reintroduced) in the bottom half of the balancer unit.
Apply assembly lube to balance shaft gear cogs.

Fit a new upgraded drive key of the correct length with retaining circlip.
Refitting is the reverse of removal noting that a special tool will be needed to retain the shafts in a specific position in the balance unit to align the drive gears and ensure they marry correctly before bolting the unit to the specific torque / angle settings.

A very small amount of backlash (backward rotation of the intermediate cog) should be present after refitting the unit.
This is necessary to avoid gear damage or excess wear.
You should have very slight rotational "play" for want of a better word when turning the lower gear cog against the intermediate one.
This is necessary to avoid gear damage or excess wear. Too tight against each other and the gear teeth will grind.

Seal sump with silicone sealant before refitting. Refit all other components removed applying correct torque settings.

CHECK: REMOVE ALL LOCKING TOOLS AND REFILL OIL!!

Rotate engine by hand a few turns to ensure free movement and no sticking of balancer unit gearing.

Reconnect battery and start up.

 

[Dannymoto]

Had hex drive changed today, New vs Old on the pictures below. My car is on 101k.

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[CoolAsIce]

Very helpful thread. My CBBB is on 69k now, I'll be changing mine in the near future for sure.

 

[Gazwould]

Had hex drive changed today, New vs Old on the pictures below. My car is on 101k.

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MASSIVE FAIL Danny !

You have replaced a 77mm for a 77mm .

The engineering fix is a remanufactured modified balancer shaft and longer harder 100mm hex key .

 

[Dannymoto]

MASSIVE FAIL Danny !

You have replaced a 77mm for a 77mm .

The engineering fix is a remanufactured modified balancer shaft and longer harder 100mm hex key .

Massive fail? Okay then.

That little wear that has been caused on the hex drive from 101,000 miles? A replaced solid hex will be fine for now I'm sure.

Not forking out hundreds of pounds for something that may never fail fully, I am aware of the problem, I have temporarily fixed the issue and will keep an eye on it.

Thank you for the "MASSIVE FAIL"

 

[Gazwould]

Yet another fails to understand the concept.

Just 0.5mm has to be worn from the hex key for the oil pump drive to be lost .

The key wears because of the poor fit into the balancer shaft keyway , so if the key looks like that what's the keyway going to be like that wasn't deep enough , hard enough and not even hexagonal to begin with ?

All you have done is put a new 77mm key in an already poorly designed keyway that now has some wear .

The new key will rapidly look like the old...

 

[Dannymoto]

Yet another fails to understand the concept.

Just 0.5mm has to be worn from the hex key for the oil pump drive to be lost .

The key wears because of the poor fit into the balancer shaft keyway , so if the key looks like that what's the keyway going to be like that wasn't deep enough , hard enough and not even hexagonal to begin with ?

All you have done is put a new 77mm key in an already poorly designed keyway that now has some wear .

The new key will rapidly look like the old...

Right so my car has covered 101,000 miles and the hex drive has not worn enough for the oil pump to be lost. Right or wrong?

The cost for checking the hex drive is the same as replacing other than the hex drive and clip. As I said this is a temporary fix and may replace with the 100mm in the future, as I am aware of this issue I will be monitoring the hex drives wear at each service. The steps I have/will be taking is a better solutions than spending hundreds straight away. I have replaced with a harder solid hex which is better than leaving in the original hex.

How do you know how greatly/badly the solid 77mm hex will perform?


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[Gazwould]

Because you haven't addressed the principal cause of the whole debacle , the balancer shaft keyway !

My dad's 77mm hex drive lost drive at 83K .

 

[Dannymoto]

Because you haven't addressed the principal cause of the whole debacle , the balancer shaft keyway !

This was a temporary fix, the 100mm balance shaft may be purchased in the future.


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[Gazwould]

Temporary fix and "may" don't gel , it's only temporary if you do !

The balancer shaft isn't 100mm it's the updated key , the balancer shaft keyway is regenerated with a deeper , perfectly centered , 10x harder chrome vanadium insert welded in that is actually hexagonal to receive the hexagonal 77mm key .

Here's my dad's failed 77mm against new 100mm , so how close were you ?

Now stop being daft and properly engineering fix your car for £215 + labour or diy .

 

[Dannymoto]

Temporary fix and "may" don't gel , it's only temporary if you do !

The balancer shaft isn't 100mm it's the updated key , the balancer shaft keyway is regenerated with a deeper , perfectly centered , 10x harder chrome vanadium insert welded in that is actually hexagonal to receive the hexagonal 77mm key .

Here's my dad's failed 77mm against new 100mm , so how close were you ?

Now stop being daft and properly engineering fix your car for £215 + labour or diy .

Refer to pictures I posted yesterday. Not as badly worn as your dads, what mileage was your dads on?


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[Gazwould]

It won't be , the idiot drove on home from a village a few miles away , lol .

The next day he fitted a new oil pressure sensor and drove it up the road till the red , stop, low oil pressure came on , the car was then retired to the driveway and research began .

How he got away with not borking the engine and turbo I'll never know .

Then the penny dropped VAG had engineered it to fail outside the warranty .

Disgusting .

 

[90tdi]

Hello,

I've been researching this problem as I have had some issues with my own car.

2013 A4 140 TDI. I don't know the engine code.

I've been getting intermittent oil pressure warnings. I'd stop the car and the warning would go away in the time it would take me to slow to a stop. It was only ever on about 5 seconds at at time.

Would the 2013 engine still have these issues? I'm not finding much about post 2009 engines.

Are intermittent and very short warnings symptomatic of this problem? My guess would have been, once the shaft is worn enough to "skip" or spin in the keyway, it's going to be permanently gone and result in a long term or constant oil warning.

Thanks!

 

[SootySport]

I've no idea if your oil pump is of a similar design but I can suggest another well known problem that can cause these symptoms.
If your engine is on Long Life servicing then oil sludge can build up in the sump and block the oil pick up pipe. To find out if this is your problem then the sump and pick up pipe need to be removed and cleaned.

 

[90tdi]

I've no idea if your oil pump is of a similar design but I can suggest another well known problem that can cause these symptoms.
If your engine is on Long Life servicing then oil sludge can build up in the sump and block the oil pick up pipe. To find out if this is your problem then the sump and pick up pipe need to be removed and cleaned.

Thanks for that. The car was purchased as an ex-fleet car so Id hazard a guess that it was on long life servicing.

The light generally only came on when going up or down hill, after relatively heavy stops so that and your info makes me hope that it is a sludge issue.

For cars who do suffer from the balance shaft problem, do you get a consistent oil light or intermittent? My oil lights never been on longer than 7 seconds, I'd say (I counted in my worry about it )

 

[SootySport]

Your engine code is printed on a sticker by the spare wheel well and in the front inside cover of the service book. It will show the engine size i.e. 2.0 then 3 or 4 letters.

 

[90tdi]

The engine code is CJCA.

The Audi dealer mechanic said he thought I was mixing my engines up as he never heard of a 2013 common rail having balance shaft issues. He said it was a PD problem more so.

 

[Dannymoto]

The engine code is CJCA.

The Audi dealer mechanic said he thought I was mixing my engines up as he never heard of a 2013 common rail having balance shaft issues. He said it was a PD problem more so.

The early Common Rail engines i.e. 2009 like you mentioned before, I believe they fixed the issue 2011/2012 with the 100mm hex drive so I wouldn't think your 2013 would have that problem and like you also suggest it would be constantly on. Like SootySport said, the oil pick up pipe is fairly common so if you drop the sump to do that it'll be worth checking the hex drive while you're at it.

 

[tesh22]

Hi,

Thanks for posting this, iv been reading into this alot but nowhere mentions the CBAB common rail engine.

I recently purchased a 58 A3 sportback it drives perfect, how will I know if this has the hollow 77mm or improved 100mm hex key setup.

How hard is it to drop the sump for inspection as a DIY check?

Thanks

 

[Dannymoto]

Hi,

Thanks for posting this, iv been reading into this alot but nowhere mentions the CBAB engine.

I recently purchased a 58 A3 sportback it drives perfect, how will I know if this has the hollow 77mm or improved 100mm hex key setup.

How hard is it to drop the sump for inspection as a DIY check?

Thanks

I can 100% assure you that the CBAB engine was affected and yours will be as it’s 58 plate. I had a 59 plate and it had the 77mm.

I wouldn’t say it’s a DIY job dropping the sump but it depends how good you are obviously, I would say next time you get the car serviced to purchase the solid 77mm hex drive (only a few £) and replace that with the hollow one or you can get the 100mm balance shaft like I did in the end.


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[tesh22]

I can 100% assure you that the CBAB engine was affected and yours will be as it’s 58 plate. I had a 59 plate and it had the 77mm.

I wouldn’t say it’s a DIY job dropping the sump but it depends how good you are obviously, I would say next time you get the car serviced to purchase the solid 77mm hex drive (only a few £) and replace that with the hollow one or you can get the 100mm balance shaft like I did in the end.


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I can 100% assure you that the CBAB engine was affected and yours will be as it’s 58 plate. I had a 59 plate and it had the 77mm.

I wouldn’t say it’s a DIY job dropping the sump but it depends how good you are obviously, I would say next time you get the car serviced to purchase the solid 77mm hex drive (only a few £) and replace that with the hollow one or you can get the 100mm balance shaft like I did in the end.


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Thanks!

Iv read alot and noted replacing only the 77mm hex is not correct. But to replace the Hex and also the Balance shaft part the Hex is seated into as this also rounds off. Read so much about buy a complete balance shaft 100mm solid hex conversion kit from KNR (i think it was).

Gutted iv had the car 1week and found out about this common fault!

 

[Dannymoto]

Thanks!

Iv read alot and noted replacing only the 77mm hex is not correct. But to replace the Hex and also the Balance shaft part the Hex is seated into as this also rounds off. Read so much about buy a complete balance shaft 100mm solid hex conversion kit from KNR (i think it was).

Gutted iv had the car 1week and found out about this common fault!

KMB parts, the kit is only £215 (exchange) plus labour of course but it makes sense to get a service done at the same time. Every car has common faults, don’t worry too much. Well done for reading up about the car you’ve bought, a lot of people done and end up with a broken engine.


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[tesh22]

KMB parts, the kit is only £215 (exchange) plus labour of course but it makes sense to get a service done at the same time. Every car has common faults, don’t worry too much. Well done for reading up about the car you’ve bought, a lot of people done and end up with a broken engine.


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KMB thats the one.

One thing, my cars on 136K wouldn this 77mm key have failed already in this which lead me to think may they fitted another. I got the car from a friend with not alot of paper work just one saying timing belts done.

 

[Gazwould]

Range is 50 - 400K miles but average is 80- 150K .

It's amazing it lasts that long as only 15mm contact length in a keyway that isn't hexagonal but splined so the very tips and no flats of the hex key are in contact .

 

[tesh22]

Range is 50 - 400K miles but average is 80- 150K .

It's amazing it lasts that long as only 15mm contact length in a keyway that isn't hexagonal but splined so the very tips and no flats of the hex key are in contact .

Hi Gazwould,

Iv read all of your posts on here regarding this, it has been extreamly helpful and I always laugh when people dont listen to you about changing both the keyway and hex!

Ok so no certainty on when it can fail, but mine is deffo going to be due soon.

How hard is it to drop the sump are there any guides on here?

Can you remove circlip and get the hex out with a magnet to inspect without taking the oilpump off?

Do you you still need to lock the engine at TDC just to inspect the hex key?

However if I dont remove the hex, but see its the hollow one we know for certain its the weak 77mm that way.

 

[Dannymoto]

KMB thats the one.

One thing, my cars on 136K wouldn this 77mm key have failed already in this which lead me to think may they fitted another. I got the car from a friend with not alot of paper work just one saying timing belts done.

Not necessarily, some fail from 40k and some don’t fail till 150k just pure luck. This was my original hex key on 110k.

I just replaced the hex drive with a solid 77mm twice to prolong it before changing to 100mm.

If you dropped the sump you would be able to see if it was hollow or solid.

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[tesh22]

Range is 50 - 400K miles but average is 80- 150K .

It's amazing it lasts that long as only 15mm contact length in a keyway that isn't hexagonal but splined so the very tips and no flats of the hex key are in contact .

Hi Gazwould,

Iv read all of your posts on here regarding this, it has been extreamly helpful and I always laugh when people dont listen to you about changing both the keyway and hex!

Ok so no certainty on when it can fail, but mine is deffo going to be due soon.

How hard is it to drop the sump are there any guides on here?

Can you remove circlip and get the hex out with a magnet to inspect without taking the oilpump off?

Do you you still need to lock the engine at TDC just to inspect the hex key?

However if I dont remove the hex, but see its the hollow one we know for certain its the weak 77mm that way.

Not necessarily, some fail from 40k and some don’t fail till 150k just pure luck. This was my original hex key on 110k.

I just replaced the hex drive with a solid 77mm twice to prolong it before changing to 100mm.

If you dropped the sump you would be able to see if it was hollow or solid.

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How hard is it to drop the sump, are ther any awkward bolts to get too as I want to inspect and also clean/change the pickup pipe anyway.

 

[Dannymoto]

Hi Gazwould,

Iv read all of your posts on here regarding this, it has been extreamly helpful and I always laugh when people dont listen to you about changing both the keyway and hex!

Ok so no certainty on when it can fail, but mine is deffo going to be due soon.

How hard is it to drop the sump are there any guides on here?

Can you remove circlip and get the hex out with a magnet to inspect without taking the oilpump off?

Do you you still need to lock the engine at TDC just to inspect the hex key?

However if I dont remove the hex, but see its the hollow one we know for certain its the weak 77mm that way.


How hard is it to drop the sump, are ther any awkward bolts to get too as I want to inspect and also clean/change the pickup pipe anyway.

I haven't personally done it before but I have seen it done and I do think there is some tricky bolts and that you'll have to seal it up again. Have a look on YouTube, probably not too difficult with the right tools.

 

[tesh22]

I haven't personally done it before but I have seen it done and I do think there is some tricky bolts and that you'll have to seal it up again. Have a look on YouTube, probably not too difficult with the right tools.

Thanks.

From your pictures i thought you did a diy.

I was just quoted £700 to supply and fit the KMB 100mm kit from a local specialist. They said they have done it many times. But that quote seems bit steep to me.

 

[Dannymoto]

Thanks.

From your pictures i thought you did a diy.

I was just quoted £700 to supply and fit the KMB 100mm kit from a local specialist. They said they have done it many times. But that quote seems bit steep to me.

That is steep, it was £370 for me at my local VAG specialist.


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[tesh22]

That is steep, it was £370 for me at my local VAG specialist.


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Was that to:

- insert your new 77mm solid Hex key
- supply and fit the 100mm kmb kit
- only fit the Kmb 100mm kit you supplied

 

[Dannymoto]

Was that to:

- insert your new 77mm solid Hex key
- supply and fit the 100mm kmb kit
- only fit the Kmb 100mm kit you supplied

Supply and fit the new KMB 100mm kit, including bolt set, sump sealant, postage back on the old 77mm kit to KMB, change oil and oil filter (I provided) & change the oil level/temp sensor in the sump (I provided).

 

[Dannymoto]

And he took pictures also:

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[tesh22]

And he took pictures also:

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Thats a damn good price, where about you located or is this garage?

I got quoted £200 fitting if I supplied KMB kit today. Better than my last quote.

I still plan to drop sump to inspect key and fit a clean pick mesh pipe too.

Alot of garages by me have said this hex key is no major issue didnt fail much and also saying dont need to worry until oil light comes on. (But i think damaged is already done by then).

 

[Dannymoto]

Thats a damn good price, where about you located or is this garage?

I got quoted £200 fitting if I supplied KMB kit today. Better than my last quote.

I still plan to drop sump to inspect key and fit a clean pick mesh pipe too.

Alot of garages by me have said this hex key is no major issue didnt fail much and also saying dont need to worry until oil light comes on. (But i think damaged is already done by then).

The garage is located in Lincoln, Lincolnshire.

Yeah worth checking it out yourself if you’re confident and should be able to check the wear too. The c clip can be a pain in the **** though and maybe snap so if you’re going to check you could just install a new solid 77mm while you’re at it?

Nah they’re wrong, when the light comes on the pressure has already dropped.


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