Dropping the sump on a 1.4 AUA

Topsie

Topsie

Member
Just thought I’d drop in a note to let people know that dropping the sump on these is a complete PITA!!!

I’ve developed a low oil pressure alarm that pops up at ~1500rpm. From experience, I believe this is a clogged oil pickup strainer which was very prevalent in the early 1.8t engines of the same era. In this case, I believe it’s because of using an oil flush on a poorly serviced unit, bring sludge from the block into the sump.

The 2 Allen bolts you have to access through the gearbox bell housing cut outs are pretty difficult to get to and are offset at an angle that really makes things difficult. I’ve got one, one to go.

If I can’t get the last, I’m pretty sure I’m going to try and snap it off with the sump itself. Any tips welcome.

Nick
 
Topsie said:
Just thought I’d drop in a note to let people know that dropping the sump on these is a complete PITA!!!

I’ve developed a low oil pressure alarm that pops up at ~1500rpm. From experience, I believe this is a clogged oil pickup strainer which was very prevalent in the early 1.8t engines of the same era. In this case, I believe it’s because of using an oil flush on a poorly serviced unit, bring sludge from the block into the sump.

The 2 Allen bolts you have to access through the gearbox bell housing cut outs are pretty difficult to get to and are offset at an angle that really makes things difficult. I’ve got one, one to go.

If I can’t get the last, I’m pretty sure I’m going to try and snap it off with the sump itself. Any tips welcome.

Nick
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Don't, (try and snap it off with the sump), you'll bruise the mating surfaces, and so will never get a leak free sump to block seal.
Mac
 
PlasticMac said:
Don't, (try and snap it off with the sump), you'll bruise the mating surfaces, and so will never get a leak free sump to block seal.
Mac
Click to expand...
I thought I had it, but sump doesn’t want to play. I’m rained off for a minute but will be back on it soon.

Good advice, I’ll try not to let my impatience get the better of me!
 
Topsie said:
Just thought I’d drop in a note to let people know that dropping the sump on these is a complete PITA!!!

I’ve developed a low oil pressure alarm that pops up at ~1500rpm. From experience, I believe this is a clogged oil pickup strainer which was very prevalent in the early 1.8t engines of the same era. In this case, I believe it’s because of using an oil flush on a poorly serviced unit, bring sludge from the block into the sump.

The 2 Allen bolts you have to access through the gearbox bell housing cut outs are pretty difficult to get to and are offset at an angle that really makes things difficult. I’ve got one, one to go.

If I can’t get the last, I’m pretty sure I’m going to try and snap it off with the sump itself. Any tips welcome.

Nick
Click to expand...

The best tool that I found for this is a ball-headed allen key:

1646054461408.png
 
Catnip64 said:
The best tool that I found for this is a ball-headed allen key:

View attachment 91578
Click to expand...
I’ve just rounded the head of the bolt - had a draper long reach round headed T-spanner and I thought I’d loosened it, but it must have slipped and rounded the head.

Going to have to get a long drill bit and drill out the head of the bolt, I just can’t get onto the bolt square enough to undo it.

What a day…
 
Topsie said:
I’ve just rounded the head of the bolt - had a draper long reach round headed T-spanner and I thought I’d loosened it, but it must have slipped and rounded the head.

Going to have to get a long drill bit and drill out the head of the bolt, I just can’t get onto the bolt square enough to undo it.

What a day…
Click to expand...
Good luck.
Before doing this perhaps try the next size up torx hammered in?
 
Does the bolt not have 10mm hex head on it, 10mm 1/4 drive socket, (best one youve got, new if possible) flexy extention and give it a good hit with hammer to shock it before you try to loosen, best of luck
 
Passatmann0 said:
Does the bolt not have 10mm hex head on it, 10mm 1/4 drive socket, (best one youve got, new if possible) flexy extention and give it a good hit with hammer to shock it before you try to loosen, best of luck
Click to expand...
Unfortunately not, just a round headed Allen bolt! I’ve got a long 8mm HSS drill bit for tomorrow morning, it’s going to be a pain to drill the head of the bolt, that’s for sure.
 
Thats mighty strange if these bolts are the same as those used on a TDI. I use a long 3/8 allen key ball end socket, worth its weight in gold at times but as said a 1/4 drive u/j with shallow 10mm may work
 
Excuse me for mentioning, but isn’t the best thing to do at this point to remove the gearbox and get proper acces?
I doubt anything good will come from the foreseen solutions thus far.

Of course I hope you get it sorted.
 
DuncanA2 said:
Excuse me for mentioning, but isn’t the best thing to do at this point to remove the gearbox and get proper acces?
I doubt anything good will come from the foreseen solutions thus far.

Of course I hope you get it sorted.
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I will take my hat off to anyone who can drill the head off one of those bolts, it really is a job where the correct tools are needed before you begin (based on tdi).
Wish you the best of success thou!!
 
Drilling would be my last resort, and only then if a garage had refused to remove the bolt. I "thought" all the bolt heads were visible looking at the sump and not through the bell housing. A long ball end Allen socket is the tool of choice.
 
The AUA and BBY crankcases sumps, and indeed the associated gearbox cases are all alloy and require careful, skilled handling. As the OP has found, it's all too easy to make a difficult job a lot harder by treating these as if the main components were cast iron.

You need to be in possession of a good torque wrench with the correct range for this job to reattach the sump properly.

The Audi workshop manual covers this procedure here:

Audi Workshop Service and Repair Manuals > A2 > Power unit | 4-cylinder petrol injection engine (1.4 ltr.), mechanics | Engine lubrication | Lubrication system | Removing and installing sump

A2 > Audi Workshop Service and Repair Manuals > Power unit | 4-cylinder petrol injection engine (1.4 ltr.), mechanics | Engine lubrication | Lubrication system | Removing and installing sump
workshop-manuals.com
 
To be clear, a good quality long headed allen T-bar, which is the correct tool, was used. The bolts are round headed Allen bolts and do not have a 10mm hex head. The head of the bolt is positioned in such a way that a 5mm allen headed socket will not fit as it is impacted by the gearbox.

I really do appreciate the advice, but not when it’s assumed that I’ve used the wrong tools for the job. I’m aware that drilling the head of the bolt is certainly not the ideal solution, but is the lesser of 2 evils (the other being to remove the gearbox) in my opinion.
 
If you haven't already, refit the bolts you have removed, and hand tighten them. That'll take the load off the problem bolt.
Mac.
 
Topsie said:
To be clear, a good quality long headed allen T-bar, which is the correct tool, was used. The bolts are round headed Allen bolts and do not have a 10mm hex head.
Click to expand...

These bolts were originally torqued to 15 Nm, hardly a massive figure. In old age they can unfortunately be difficult to remove not because they were over-tightened but because they are steel bolts screwed into aluminium alloy, and bimetallic corrosion has gained a grip.

I believe that the bolts in question have a 12-point triple square socket, although long male keys are not easily available for these. The 12-point socket works pretty well with other key types (which presumably is part of its appeal) and of course Audi specifically recommend the ball hex socket to undo these.

Bimetallic corrosion can be a nightmare to get past at the best of times, even with full access to the bolt, so I certainly sympathise
 
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steve_c said:
These bolts were originally torqued to 15 Nm, hardly a massive figure. In old age they can unfortunately be difficult to remove not because they were over-tightened but because they are steel bolts screwed into aluminium alloy, and bimetallic corrosion has gained a grip.

I believe that the bolts in question have a 12-point triple square socket, although long male keys are not easily available for these. The 12-point socket works pretty well with other key types (which presumably is part of its appeal) and of course Audi specifically recommend the ball hex socket to undo these.

Bimetallic corrosion can be a nightmare to get past at the best of times, even with full access to the bolt, so I certainly sympathise
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When refitting bolts like these, is there a precaution that can be taken to minimise the bimetallic/galvanic action, such as anti-seize compounds?
Mac.
 
steve_c said:
These bolts were originally torqued to 15 Nm, hardly a massive figure. In old age they can unfortunately be difficult to remove not because they were over-tightened but because they are steel bolts screwed into aluminium alloy, and bimetallic corrosion has gained a grip.

I believe that the bolts in question have a 12-point triple square socket, although long male keys are not easily available for these. The 12-point socket works pretty well with other key types (which presumably is part of its appeal) and of course Audi specifically recommend the ball hex socket to undo these.

Bimetallic corrosion can be a nightmare to get past at the best of times, even with full access to the bolt, so I certainly sympathise
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Are these bolts hex socket head, 12 point Torx, or 12 point star?
Mac.
 
Thought I’d give a progress update.

The offending bolt head has been drilled out, which was overall relatively easy.

One problem solved, which creates another.

The sump needs to slide out before being dropped down, but is now caught on the remaining bolt. I’ll hammer in a flat headed screw driver to remove, it’s at least loose now.

The reason I couldn’t get purchase is almost laughable - the metal gasket that sits between the gearbox and engine had been bent (possibly by a clutch change previously in the cars life) and was blocking what I’d call direct access to the bolt head.

This wasn’t immediately obvious (there’s not a lot of room to really see what’s going on) until I started drilling. All could have been avoided with a screwdriver and a bit of elbow grease!!
 
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