Withdrawal
Note: If the pistons/connecting rods do not need to be repaired, it is not necessary to remove the cylinder head and pistons. It is only necessary to push the pistons deep enough into the cylinders so that the connecting rods move away from the crankshaft crankpins. It is strongly recommended to use a special frame designed for engine repair.
1. Guided Section 1A, do the following:
- a) Remove the crankshaft sprocket and toothed drive belt.
- b) Remove clutch components and flywheel or drive plate (depending on the model).
- c) Remove the sump, baffle, oil pump and suction tube.
- d) Remove the crankshaft rear oil seal and its casing.
2. Remove the pistons and connecting rods or disconnect them from the crankshaft as described in Chapter 7 (see note above).
3. Turn the cylinder block over on a workbench and check the crankshaft end play as follows. Install the micrometer so that its probe is located on the axis of the crankshaft and touches the end of the shaft. Move the crankshaft all the way to one side and set the micrometer to zero. Move the crankshaft to the stop in the opposite direction and write down the resulting axial clearance (see illustration). Comparing the result with the figure given in the Specifications will show if new thrust washers are required.
4. If a micrometer is not available, feeler gauges can be used. First, move the crankshaft all the way to the flywheel, then select the feeler gauge, the thickness of which corresponds to the gap between the counterweight of the connecting rod journal of cylinder No. 4 (5 cylinder engines) and thrust washer of the main bearing (see illustration). Compare the results with the data given in the Specifications.
5. Pay attention to labels of covers of radical bearings. The number indicates the position of the cover in the crankcase, cover #1 is closest to the toothed drive belt (see illustration).
6. Loosen the main bearing cap bolts by turning them half a turn at a time and remove them (see illustrations). Tap the covers lightly with a mallet and separate them from the crankcase. Remove the lower main bearing shells, attaching them to the appropriate cover for safety with adhesive tape. Mark them so as not to confuse them, but do not scratch or gouge them.
7. Carefully lift the crankshaft out of the crankcase, being careful not to dislodge the upper main bearing shells (see illustration).
8. Remove the upper bearing shells from the crankcase, and tape them to their respective bearing caps. Remove two thrust washers from bearing #4 (5 cylinder engines).
9. Remove the liners and pay attention to the recesses in the bearing caps and crankcase designed for the mounting tabs of the liners.
Inspection
10. Wash the crankshaft in a suitable solvent and allow it to dry. Thoroughly clean the oil holes,» using a suitable brush, if necessary.
11. Inspect the necks of the main and connecting rod bearings. If there are signs of uneven wear, cracks, scratches or pitting, have a professional regrind the crankshaft and install it to the engine with oversize bushings.
12. Using a micrometer, measure the journal diameter of each main bearing (see illustration). Take measurements at several points around each neck to identify possible ovality. Take a measurement at the ends of the neck, near the counterweights, to determine if the neck is tapered. If such wear is detected, have a specialist regrind the crankshaft and purchase oversized liners.
13. Check the seal contact areas at both ends of the crankshaft. If worn out or damaged, new seals will be damaged during engine reassembly and will therefore leak. It may be possible to regrind the end of the shaft - contact an Audi dealer.
14. Measure crankshaft runout by placing a micrometer probe on the 3rd and 4th main bearings (5 cylinder engines) and rotating the shaft on V-shaped props. The maximum deviation of the micrometer needle corresponds to the beat. Be careful not to damage the bearing journals or seal contact surfaces during this procedure. Manufacturers do not give the maximum allowable runout value, but approximately it is 0.03 mm. If the runout exceeds this value, consult your Audi dealer for crankshaft replacement.
15. Inspection of main and connecting rod bearings is described in Chapter 10.
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