Timing Belt and Sprockets
Removal
1. Remove the cable from the negative battery terminal.
2. Chock the rear wheels and apply the parking brake.
3. Loosen the nuts on the right front wheel, raise the front of the car and place it on safety supports.
4. Remove the right front wheel and lower protective cover.
5. Remove the power steering pump reserve tank and its bracket (see chapter 10). If the anti-lock brake system (ABS) is installed, remove the ABS actuator and its bracket (see chapter 9).
6. Remove the spark plugs and the accessory drive belts (see Chapter 1A).
7. Remove the generator and its bracket (see chapter 5).
8. Support the engine with a jack, placing a piece of board between the jack and the engine sump, remove the right support and engine support rod (see paragraph 16).
9. Remove the bolts from the top cover, lift up the wiring harness and remove the top (pos. 2 in Figure 7.9) timing belt cover and gaskets (see Figure 7.9).
Figure 7.9. Timing drive components.
10. Set the piston of cylinder No. 1 to TDC of the compression stroke (see paragraph 3). Make sure the label is (small hole) the timing on the camshaft pulley coincided with the TDC mark on the outer camshaft support cover (see Figure 7.10).
Figure 7.10. Align the timing mark on the camshaft sprocket with the TDC mark of cylinder No. 1.
11. If you are going to reuse the timing belt, mark the sprocket and belt and use an arrow to indicate the direction of belt rotation (see Figure 7.11).
Figure 7.11. If the timing belt is to be reused, mark the timing belt and the camshaft sprocket with alignment marks (indicated by an arrow).
12. Loosen the upper (No. 1) tension roller mounting bolt and unhook the spring (see Figure 7.12).
Figure 7.12. Release the locking bolt and unhook the spring.
Remove the belt from the sprocket. If you are replacing the camshaft seals or removing the cylinder head, there is no need to remove the entire belt - just remove the top portion of the belt from the camshaft sprockets.
13. If the camshaft sprocket is worn or damaged, remove the valve cover and, holding the camshaft by the hexagon with a long open-end wrench, use another wrench to unscrew the sprocket mounting bolt and remove it (see Figure 7.13).
Figure 7.13. Remove the valve cover and loosen the camshaft sprocket mounting bolt, holding the camshaft from turning with a long open-end wrench on the camshaft hexagon. Do not use tensioning the timing belt to prevent the camshaft from turning.
14. Unscrew the crankshaft pulley mounting bolt using a socket and a ratchet (see Figure 7.14,a).
Figure 7.14,a. Remove the flywheel/faceplate protective cover and secure the crankshaft by inserting a powerful screwdriver into the flywheel ring gear or resting it against the torque converter mounting bolt, then loosen the crankshaft pulley mounting bolt with a socket with a suitable sized wrench or extension – the bolt is now very tight.
To prevent the crankshaft from turning, remove the flywheel cover, insert a large screwdriver between the flywheel ring teeth/faceplate, or press it against the torque converter mounting bolt. After releasing, unscrew the pulley mounting bolt and remove the pulley, prying it off with two mounting blades (see Figure 7.14,b).
Figure 7.14,b. Often the crankshaft pulley can only be removed using pry bars or a puller. When removing, rest the tool only on the pulley hub (do not use a puller with short jaws).
To avoid damaging the vulcanization of the damper, it should only be pried under the hub. Before removing the pulley, carefully check the position of the crankshaft - it should correspond to the TDC of the piston of cylinder No. 1.
15. Remove the lower (pos. 1) timing belt cover with gaskets (see Figure 7.15), then remove the timing belt guide washer from the crankshaft sprocket.
Figure 7.15. Loosen the timing belt lower cover mounting bolts (shown by arrows) and remove it together with the gasket from the engine.
16. If you are going to reuse the belt, make timing marks on the belt and crankshaft sprocket (see Figure 7.16).
Figure 7.16. If the timing belt is to be reused, apply timing marks to the timing belt and the crankshaft sprocket.
17. Remove the timing belt from the sprocket and place it in a plastic bag to avoid accidentally getting it dirty. If the sprocket is worn or damaged, or the crankshaft seal needs to be replaced, remove the sprocket from the crankshaft (see figure 7.17,a,b).
Figure 7.17,a. The crankshaft sprocket should be easy to remove.
Figure 7.17,b. If the crankshaft sprocket cannot be removed by hand, use a puller.
Examination
Warning. The timing belt should not be folded, twisted or turned inside out. Do not allow oil, coolant or fuel to come into contact with its surface. Do not use timing belt tension to prevent the crankshaft or camshaft from turning when tightening the sprocket mounting bolts. Do not rotate the crankshaft or camshaft more than a few degrees (only if necessary to align the teeth) with the belt removed.
18. Remove the tension rollers and check the condition of the bearings for jamming and excessive play. Inspect the spring and measure its length in its free state. Compare the measurement result with the Specifications standard (see Figure 7.18).
Figure 7.18. Check the condition of the tension roller bearing and measure the length of its spring in the free state.
19. If the belt breaks while the engine is running, it means that it was dirty or too tight.
20. If the belt is cracked or its teeth have crumbled (see Figure 7.20), this indicates that the oil pump, water pump or camshaft is jammed.
Figure 7.20. Inspect the timing belt and make sure there are no defects. One-sided wear indicates misalignment (vertical misalignment of the stars) when installing the belt.
Warning. When the timing belt breaks, the valves can "meet" the pistons, which almost always leads to their damage. Measure the clearances in the valve drive mechanism (see Chapter 1A). Bent valves will have higher clearances than normal, which indicates the need to remove the cylinder head for repair.
21. If there are signs of increased wear or cracks on the working surface of the timing belt, inspect the tension rollers to ensure there are no nicks or burrs on them.
22. If the belt shows wear and damage on one side, check the belt guide gear and the correct fit of the sprockets relative to each other in the vertical plane (absence of distortion).
23. Replace the timing belt if excessive wear or damage is evident or if there is any doubt about its condition. Before installing a new belt, identify the causes of damage and wear and eliminate them.
Note: Professionals recommend replacing the timing belt every time it is removed, as the cost of a new belt is incomparable to the cost of engine repair if it breaks. The manufacturer recommends replacing the timing belt every 95,000 km.
Installation
24. Wipe all components in the front of the engine compartment around the timing belt with a rag.
25. If removed, install the tension rollers and tension spring. Overcoming the resistance of the spring, pull the upper (No. 1) tension roller as far as possible and temporarily tighten the bolt. Also, if removed, install the sprockets on the crankshaft and camshafts. The crankshaft sprocket must be installed with the side with the timing teeth of the crankshaft position sensor facing the oil pump.
(This material is taken from a resource: ToyotaMAN)
26. Make sure that the timing marks on the camshaft and crankshaft are aligned exactly. The small hole in the camshaft sprocket should be aligned with the mark on the outer camshaft support cover (see item 10), and the keyway on the crankshaft sprocket should be exactly opposite the TDC mark of the piston of cylinder No. 1.
27. Install the timing belt on the crankshaft sprockets, oil pump, water pump and on the tension rollers. If you are installing an old belt, align the timing marks made when removing it (see paragraphs 11 and 16).
28. Place the guide washer on the crankshaft, with the marks from the teeth towards the belt (see Figure 7.28).
Figure 7.28. The guide washer is installed with the marks from the teeth facing the belt.
29. Install the lower timing cover and crankshaft pulley. Check the alignment of the TDC marks.
30. Place the belt on the camshaft sprocket, applying tension from the side closest to the front of the vehicle (see Figure 7.30).
Figure 7.30. When installing the belt, its front shoulder must be taut.
If you are installing an old belt, align the timing marks made when removing it.
31. Loosen the bolt on the upper (No. 1) tension roller by 1/2 turn, activating the tension roller spring.
32. Slowly turn the crankshaft clockwise 1 and 7/8 turns and align the mark on the crankshaft pulley with the 45° BTDC (before TDC of piston No. 1) mark on the lower timing cover, then tighten the tension roller bolt to the specified torque (see Specifications).
33. Turn the crankshaft another 2 and 1/8 turns until the TDC marks are aligned and check the valve timing marks again (figure 7.33).
Figure 7.33. Alignment of valve timing marks when cylinder No. 1 is at TDC of the compression stroke.
The hole on the camshaft sprocket must be aligned with the timing mark on the outer camshaft support cover. If the marks do not match exactly as shown in the figure, the belt installation procedure must be repeated.
Warning. Do not start the engine unless you are absolutely sure the timing belt is installed correctly. Starting the engine with an incorrectly installed belt can result in serious and costly repairs.
34. Install all remaining components in the reverse order of removal.
Note: If the timing cover gaskets are damaged, clean the mating surfaces and apply new gasket sealant (see Figure 7.34).
Figure 7.34. Apply sealant gasket to the timing belt covers where the black thick line is drawn.
35. Start the engine and make sure it operates normally.