4.6. Peredny Bridge

POSSIBLE MALFUNCTIONS OF PEREDNY BRIDGE, THEIR REASON AND METHODS OF ELIMINATION



The main transfer and differential of the forward bridge on a design are similar to the back bridge. All instructions on service and repair of the back bridge belong as well to the forward bridge.

Fig. 3.98. Rotary fist: and – an alarm flute; – the index; I – right rotary fist; II – the left rotary fist; III – the coupling of shutdown of wheels; IV – the coupling of shutdown of wheels (alternative execution); in – wheels are disconnected; – wheels are included; 1 – lever of a rotary fist; 2 – half shaft casing;
3 – epiploon; 4,20 – laying; 5 – spherical support; 6 – case of a rotary fist; 7 – basic washer; 8 – slip; 9 – pivot axle; 10 – press butterdish;
11 – lock pin; 12 – pin; 13 – wheel nave; 14 – leading flange; 15 – coupling; 16 – coupling bolt; 17 – clamp ball; 18 – protective cap;
19 – plug шкворня; 21 – internal holder; 22 – ring partition;
23 – external holder; 24 – rubber sealing ring; 25 – felt sealing ring; 26 – persistent washers; 27 – turn restriction bolt; 28 – emphasis limiter of turn of a wheel; 29 – ring; 30 – leading shchlitsevy plug; 31 – connecting shlitsevy plug; 32 – leading plug; 33 – cap; 34 – cover; 35 – cuff; 36 – pin; 37 – switch;
38 – ball; 39, 41 – springs; 40 – laying; 42 – the conducted plug; 43 – rastyazhny spring; 44 – case; 45 – locking ring


Service and repair of rotary fists (fig. 3.98) is in addition made.

Maintenance
At maintenance of the forward leading bridge check and if necessary adjust an inhaling of bearings shkvorny, a convergence of wheels and the maximum angles of rotation of wheels, check and tighten fastening of the lever of a rotary fist, wash out and replace lubricant in rotary fists. At survey of rotary fists pay attention to serviceability of an emphasis limiters of 28 (fig. 3.98) of turn of wheels, adjusting bolts 27 and reliability of their latching.
Shkvorny on the car you make check and adjustment of an axial gap in the following order:
1. Slow down the car the parking brake mechanism or put blocks under back wheels.
2. Lift the forward bridge a jack.
3. Turn off nuts of fastening of a wheel and remove it.
4. Turn off bolts of fastening of an epiploon of a spherical support and remove an epiploon.

Fig. 3.99. Check of adjustment shkvorny: 1 – top slip; 2 – adjusting laying; 3 – pivot axle; 4 – lower slip



5. Check an axial gap shkvorny for what shake hands the case of a rotary fist (fig. 3.99) up and down.
6. Turn off nuts of hairpins of fastening of the lever 1 (see fig. 3.98) a rotary fist or bolts of fastening of the top slip 1 (see fig. 3.99) and remove the lever or the top slip шкворня.
7. Take out thin (0,1 mm) adjusting laying and install the lever or an overlay for the place.
8. Turn off bolts of fastening and remove the lower slip 4 шкворня, take out thin (0,1 mm) adjusting laying and establish a slip шкворня into place.
For preservation of coaxiality of the hinge take out laying of identical thickness from above and from below.
Check results of assembly. If the gap is not eliminated, make repeated adjustment due to removal of thicker laying (0,15 mm).
Big wear shkvorny 9 and plugs 19 (see fig. 3.98) on diameter causes violation of a corner of disorder of wheels, their "wagging" when driving and uneven wear of tires. In this case replace worn-out details.

Fig. 3.100. Check of the maximum angles of turn of wheels



You make check of the maximum angles of rotation of wheels at the special stand (fig. 3.100). The angle of rotation of the right wheel to the right, and the left wheel has to be no more than 27 ° to the left. You make adjustment a bolt 27 (see fig. 3.98).
Regulate a convergence of wheels change of length of cross steering draft. Before adjustment be convinced of lack of gaps in hinges of steering drafts and bearings of naves; then, having weakened an inhaling of the lock nuts (having the right and left carvings), establish by rotation of the adjusting union the necessary size of a convergence of wheels.

Fig. 3.101. Check of a convergence of wheels



The convergence of wheels with a normal pressure in tires has to be such that the size A (fig. 3.101) measured on the average line of a side surface of tires in front was 1,5-3,0 mm less than the size B behind.
Upon termination of adjustment tighten lock nuts. Moment of an inhaling of 103-127 N · m (10,5–13 kgfs · м).
The convergence of wheels can be checked a line of the GARO model 2182.

Repair
For carrying out repair remove the forward leading bridge from the car and sort.
After dismantling and washing of details check their state and reveal their suitability for further work.
And differential you make repair of a case, the main transfer according to the instructions stated in the section "Zadny Bridge". At a half shaft casing bend you make its editing in a cold state. Replace worn-out details of rotary fists new, using these tab. 3.9.
You make removal of the forward bridge in the following order:
1. Establish blocks under back wheels of the car.
2. Disconnect on the left and right longerons pipelines of the hydraulic brake system from the flexible hose going to brake mechanisms of forward wheels. Turn off nuts of fastening of flexible hoses and remove them.
3. Turn off nuts of fastening of the lower ends of shock-absorbers.
4. Turn off bolts of fastening of the forward driveshaft to a flange of the leading gear wheel.
5. Rasshplintuyte also turn off a nut of a spherical finger of a bipod, having disconnected draft from a bipod.
6. Turn off nuts of fastening of step-ladders of forward springs, remove linings, step-ladders and slips. Lift a forward part of the car for a frame.

Note
At removal of the bridge with a spring suspension bracket execute operations 1-5. Then disconnect the stabilizer 16 (see fig. 196) cross stability from longitudinal levers of 1 suspension bracket, cross draft 2 from an arm 11 on a frame, the back ends of longitudinal levers 1 from arms 5 on a frame.

 Dismantling of the forward bridge
You make dismantling of the forward bridge in the following order:
1. Install the bridge on the stand, turn off nuts of wheels and remove wheels.
2. Rasshplintuyte also turn off a nut of fastening of a finger of thirst of a bipod for the lever of a rotary fist and remove draft of a bipod.
3. Unscrew screws and remove brake drums.
4. Remove couplings of shutdown of wheels.
5. Straighten the unbent edges of a key washer, turn off a nut and a lock-nut, remove a lock washer and an internal ring with rollers of the external bearing of naves of the right and left wheels.
6. Remove naves of wheels.
7. Turn off bolts of fastening of brake boards, remove boards, pins of rotary fists and take out hinges of rotary fists.
8. Rasshplintuyte also turn off nuts of fastening of fingers and remove draft of a steering trapeze.
9. Turn off bolts of fastening of a spherical support to a half shaft casing. Remove an emphasis limiters of turn of wheels and a vypressuyta spherical support from casings of half shafts.
10. Turn off nuts of fastening of the rotary lever on the case of a rotary fist. Remove the lever and a set of adjusting laying.
11. Turn off bolts of fastening of the top slip шкворня other rotary fist and remove a slip with a set of adjusting laying.
12. Turn off bolts of fastening of the lower overlays of shkvorny and remove slips with a set of adjusting laying.
13. Turn off bolts of fastening of an epiploon of a spherical support and remove an epiploon of a spherical support.

Fig. 3.102. Stripper shkvorney



14. Vypressuyte of a shkvorna by means of adaptation shown in fig. 3.102 also remove the case of a rotary fist.
You make dismantling of a rotary fist without removal of the forward bridge from the car in the following order:
1. Substitute blocks under back wheels of the car.
2. Lift a jack a forward wheel from the party demanding dismantling.
3. Execute the operations stated above in points 2-10 of this chapter.
4. Turn off nuts of fastening of the rotary lever or bolts of fastening of the top slip шкворня on the case and remove the lever or a slip with a set of adjusting laying.
5. Turn off bolts of fastening of the lower slip шкворня and remove a slip with a set of adjusting laying.
6. Turn off bolts of fastening of an epiploon of a spherical support.
7. Vypressuyte of a shkvorna adaptation also remove the case of a rotary fist.
 Dismantling and assembly of hinges of equal angular speeds
You make dismantling of hinges in the following order:
1. Note paint a relative positioning of fists of hinges.
2. Part fists, for this purpose knock with a fork of a short fist on a wooden support.
3. Clamp in a vice the hinge for a long fist a short fist up.

Fig. 3.103. Dismantling of the hinge



4. Turn a short fist towards one of the leading (peripheral) balls. If at the same time the opposite ball does not leave flutes, press or hit with the copper hammer (fig. 3.103) on a short fist. At the same time be careful as one of balls can take off from the hinge with high speed.
5. Take out other balls of the hinge. After selection of new balls of the increased size (repair) or replacements of one of fists collect the hinge.
You make assembly of hinges in the following order:
1. Clamp in a vice a long fist in vertical position.
2. Insert the central ball.
3. Establish a short fist on the central ball so that the tags noted by paint coincided and, turning it here and there, establish serially three leading (peripheral) balls.
4. Part fists on 10–12 mm and turn a short fist on the maximum corner from free flutes aside, establish the fourth ball in flutes.
5. Turn a short fist in vertical position.
The tightness at balls of the hinge has to be such that the moment necessary for turn of a fist on 10-15 ° extensively from a vertical at other fist clamped in a vice, equaled 30–60 N · m (300–600 kgfs · cm).
The difference in the moments of turn of a fist in two co-perpendicular directions of one hinge should not exceed 9,8 N · m (100 kgfs · cm). For receiving the required tightness and ensuring the correct assembly balls have to be sorted on 9 groups.
The sizes of diameters of the leading balls of the hinge of equal angular speeds in mm:
      I......        25,32-25,34 VI...... 25,42–25,44
       II.       25,34-25,36VI...... 25,44–25,46
       III.      25,36-25,38VIII...... 25,46–25,48
       IV.      25,38-25,40IX...... 25,48–25,50
       V...... 25,40–25,42
Diameter of the central ball is 26,988–0,05 mm. Each hinge has to gather with balls of one group or two next groups.
For example: two balls with a diameter of 25,41 mm and two balls with a diameter of 25,43 mm. At assembly balls of one size surely arrange oppositely to one another. The difference in the diameters of two couples balls of one hinge is allowed no more than 0,04 mm.
After assembly roll the hinge at the stand within 2 minutes with a frequency of rotation of 4,8 with-1 (300 min.-1) with change of a corner from 0 to 30 °.
At a running in balls and flutes grease as directed tables of greasing.

Assembly of the forward bridge
You make assembly of the forward bridge as it should be, the return to dismantling, taking into account the following:
1. Press the plug in a pin of a rotary fist aflush with a nest end face under a persistent washer.
After a press fitting deploy the plug and iron a brooch to diameter 32 +0,34 +0,17 mm.
2. Limit longitudinal movements of the hinge of equal angular speeds by persistent washers, one of which establish in a spherical support, and another – in a pin.

Fig. 3.104. Installation of a persistent washer:
1 – persistent washer; 2 – pin; 3 – spherical support; 4 – plug


Oil flutes of persistent washers have to be turned to the hinge. For fixing of a washer in a nest to its raskernita in 3–4 points which are evenly located on a circle. The size from the plane of a persistent washer of 1 (fig. 3.104) to a flange of a pin 2 has to be 7 +0,08 - 0,26 mm, from the plane of a washer 1 to the center of a spherical support 3 – 48,2+0,38 mm.
3. When replacing in a spherical support of plugs 4 shkvorny deploy them after a press fitting to diameter of 25 +0,030 +0,008 mm. The caliber of diameter of 24,995 mm has to enter at the same time both plugs.
4. At installation of the hinge put in a spherical support lubricant according to the table of greasing.
5. Shkvorni and plugs shkvorny before assembly grease with liquid lubricant.

Fig. 3.105. Selection of adjusting laying: 1 – spherical support; 2 – basic washer;
3 – pivot axle; 4 – adjusting laying;
5 – case of a rotary fist


Choose the number of laying as shkvorny for receiving certain axial tightnesses in plugs depending on the size B (fig. 3.105) consisting of the sum of the sizes of a rotary fist and adjusting laying, and the size A consisting of the sum of the sizes of a spherical support, basic washers and shkvorny. The number of laying has to be not less than five.
Measurement you produce 1,6 kN (160 kgfs) under loading. The size A has to be 0,02-0,10 mm more than the size B.
Establish adjusting laying from above and from below on end faces of the case of a rotary fist. At even number of laying, identical on thickness, establish the last from above and from below in identical quantities.
At even number of laying, but their different thickness, or at odd number of laying the difference between the total thickness of the top and lower laying should not exceed 0,1 mm.
6. At assembly and installation of an epiploon of a spherical support impregnate its internal felt ring in warm engine oil.
7. After assembly check the forward bridge at the stand under loading and without it. Loading is created by simultaneous snubbing of both half shafts.
Correctly collected forward bridge should have no increased noise and heating, and also an oil leak through cuffs and epiploons, covers and bolt connections.