Many Diesels of the VW/ Audi, Skoda, Seat and some fords use a PD Engine (Pump Duece) Made In Germany. There are the 1.9l --8 Valve SOHC Type & A; 2.0l16V DOHC Type. Some of these engines utilise a Balance-Shaft Assemble which Is Driven by the Crank-Shaft. It is used for the harmonic balancing of the engine in the high rev. range to dampen destructive vibration. They also utilize a Dual Mas Flywheel for the same reason.
The reason for this instructable is One of the shafts actually has a Hex-Drive And Hex Rod which runs the Oil-Pump -// for some reason the drive in the shaft is weak!!! & Eventually wears the hex round and you lose oil pressure!!!! Worst case scenario is Engine Failure and new engine & Turbo......
[If Your Did Not Stop To Wonder Why Your Car Was Noisy And Carried On Driving!!!!!]
You can buy these units recondition on Ebay for a pretty penny or buy a whole unit for a Grand! ---
Fortunately I have Perfected a sound repair that will save money....
Step 1: Tools You Need to Use for the Job
Mini Lathe & Centering Jig Steady ////Centering End Stock [With Bearing] , High Tensile Cutting Tool-Bit
Plumbers Gas Torch
Belt Sander /Journal Polisher
Old [OIL Pump Unit For New Drive Spindle]
Torch & Air line & Goggles
20/ 30 TON Press /Fly Press /Or VICE MAY BE POSSIBLE [Lock-Tight only If Necessary]
Step 2: Set Up & Drilling Proceedure
//Well the stock material for repairing this shaft is practically unavailable on the net.......The Mind Maybe Puzzled by now.??
As You may realise, for the successful repair of your engine you will have to replace :- //The Crank-Shaft [If Scrap] A New Con-Rod, B/ends & Main Bearings And The OIL-PUMP See Image  Yes Its knackered! So We Press ON?
From Images [1,2,3] You can see how we proceed, by pressing the centre drive from Oil-PUMP.........
Next Image  we tighten end of the Balance shaft-journal in our lathe chuck. Next we take lathe Tail-stock with centre and we lock it. Clock the journal to make sure there is little Run-Out Use soft hammer to correct. Image  We Take Our Lathe-Centre-Steady and Clamp It Around, [With Fingers Loose] Now we Push Fingers Equidistant with a little pressure, we lock individually 10mm Spanner. Now Apply a little oil --Lathe Speed Is Critical The Balance Shaft Counter Weight Will Cause The Whole Lathe To Walk The Floor On Fast Speed, Set To Image  Or Until Lathe IS STEADY.
Take Centre Out Of Tail Stock & Replace With Drill Chuck.......Place A Very Sharp Drill A 8MM Drill Piece In Lock Tail Stock And Gently Feed Drill ---Otherwise it will cause shaft to wobble ever so slightly, causing taper. Drill To A Depth Where All Original Hex Pressings Disappear. Because when the hex was put in, it was formed from a Circular hole and then a Hot Hex Die would have been pressed into the hole to full depth, with a relief depth for the swarf and there you have it. We have to drill out this material to just over an inch [25/30mm] .
Step 3: Drilling Continued
Now We Drill To Depth when the drill will start to make a chipping noise, using air-line and torch check hole it should be clear to the bottom. Our Spindle from the Oil-Pump is dead on size [12.0 mm] but we need machining allowance.
We now put a very sharp 11.0mm Drill and proceed as before [Slow Feed] Even pressure.
We Now Use a 11.5mm Drill & repeat previous step.
Next Stage [Image 2] is based on what measurement you have with the hole you have drilled even a sharp drill will increase finished bore size by a small margin of microns /thou. Take this measurement and transpose to the our Spindle. We Need To achieve .0005-.001 or 12.5-25.4 Mic interference fit.
There should be plenty of margin if you take your time.
Put Spindle in your lathe and machine a few thou/ mic at a time, measuring as you go, especially when you are close to the diameter needed - as this material is hard [scintered] you may need a polishing belt to smooth out any machining ridges left by your Tool. Some lathes on hard material hold a Spring Cutting Pressure //be careful of this phenomena...!!!! You can end up with a taper / which can be useful if you have the taper the right direction. Fine grit emery paper also comes in handy.
The hex drive in the centre of this spindle is only part way down the inside so we need to cut the good portion to suit our length. To measure use the Vernier Caliper Depth Rule End and measure depth of bore hole. When cutting spindle, have lathe turning. Be Very Careful & Wear Goggles. When You are through, put a Slight [1.5mm 45-60/o ANGLE] Lead Taper ON ONE END make sure if you do have a little taper caused by runout have the smaller end with the lead on it.
Image  Shows It Ready For Pressing GOOD LUCK !!!!!!!
Step 4: Pressing Our Spindle Into the Shaft
Sit/ Straddle Gear end of balance-shaft between Press Bed Plates.......Do Not Use Bearing Puller Clamps You will Cripple/ Bend or Snap Shaft. Having Straddled the Shaft between the plates we need to clear the radius on the underside of mesh gear, by putting a piece of metal underneath ether side, see illustration 
Now we have one shot -its not for the faint hearted & you could run into trouble, its easy done, no matter how careful you are- I have had several successes...... but anything could happen- just a warning!!!!!!
Using a plumbers blow-torch we have portable heat to expand our hole slighly, gently heat until a wet cloth sizzles [withdraw hea at this point] using a small amount of oil on the tip of the spindle -make ready the press [bring close to work piece, align with one hand and start pressing like a lunatic- you may hear some horrible noises if slighly too tight! or squeeking if just right ///if it drops in and you still have more pushing, Grab the lock-Tight Quickly.......
A think I have experienced all these noises on every turn! & the shaft will flex slightly too!
When Cooled Put back into lathe steady & Use angle grinder to make flush. Unless you shaft is now bent :(((( Unlikely if you were close!!!
Try New Hex Key [From Ebay OR Main-Dealer] Measure Journal Size/ It should be within spec compared to other neighbouring Journals.
I wish anyone following this instructable the best of luck.....
[This Is Pure Engineering Ingenuity]
PLEASE RATE & COMMENT