4.5. Zadny Bridge

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



Maintenance
Maintenance of the back bridge consists in maintenance of level of oil in a case and its timely replacement, check of consolidations, timely detection and elimination of axial gaps in gear wheels of the main transfer. Periodically clean the safety valve, tighten all fasteners.
If oil in a case is strongly polluted or in it metal particles are noticed, then before filling of fresh oil wash out a case kerosene. For washing fill in 1–1,5 l of kerosene in a case; lift wheels, launch the engine and let's it work 1,0–1,5 minutes then merge kerosene and fill in fresh oil.

Fig. 3.79. Zadny Bridge: 1 – safety valve; 2 – differential bearing; 3,8 – adjusting laying; 4 – back bearing of the leading gear wheel; 5 * – an adjusting ring;
6 – maslootgonny ring; 7 – nut; 9 – leading gear wheel; 10 – forward bearing of the leading gear wheel; 11 – persistent washer of a semi-axial gear wheel; 12 – the conducted gear wheel. (* Since 1991 is not established)


The axial gap of the leading gear wheel of stavny transfer is not allowed. Check a gap rocking of the leading gear wheel for a flange of fastening of the driveshaft. At emergence in use of the car of an axial gap of the leading gear wheel more than 0,05 mm tighten a nut of 7 (fig. 3.79). The inhaling moment – 167–206 N · m (17–21 kgfs · м). If a gap are not eliminated, make adjustment as it is specified in the head "Assembly and adjustment of knots of the back bridge".
The axial gap of the conducted gear wheel of the main transfer is not allowed. It you make check movement of a gear wheel through an oil-filling opening. For elimination of a gap add sets of laying, identical on thickness, between end faces of differential and bearings.
Do not add sets of laying of different thickness and do not establish them on one side from the conducted gear wheel since it will lead to violation of gearing of the earned extra gear wheels and their bystry breakage.

Repair
 Dismantling of the back bridge
You make dismantling of the bridge in the following order:

Fig. 3.80. Installation of the bridge at the stand


1. Install the bridge on the stand (fig. 3.80), turn off traffic jams of oil-filling and masloslivny openings and merge oil.
2. Turn off bolts of fastening of half shafts and with their help remove half shafts.
3. Turn off nuts and bolts of fastening of a cover and a case, carefully separate the bridge on two parts. Remove laying.
4. Take out from a case differential with the conducted gear wheel assembled.
5. Remove the leading gear wheel of the main transfer. Without sorting the bridge, it is impossible to remove the leading gear wheel as at a gear wheel vypressovka with bearings assembled from a bridge case the back bearing (with cylindrical rollers) will rest against the conducted gear wheel.

Fig. 3.81. Vypressovka leading gear wheel


For removal to the rasshplintuyta conducting gear wheels also turn off a nut on a shaft, remove a washer and a flange, turn off bolts and uncover the forward bearing of the leading gear wheel. Remove a maslootgonny ring, a vypressuyta adaptation the leading gear wheel (fig. 3.81) with bearings assembled from a case.
6. Sort differential in the following order:
– turn off bolts of fastening of the conducted gear wheel to a box of satellites; remove the conducted gear wheel;
– turn off bolts of fastening of half of a box of satellites;
– disconnect the right half of a box of satellites from left and take gear wheels of differential, an axis of satellites and basic washers.
 Assessment of technical condition of details
After dismantling of the bridge of a detail carefully wash out in kerosene and examine.
With teases and a vykrashivaniye on teeths replace gear wheels.

Fig. 3.82. Vypressovka external ring of the bearing of differential


Fig. 3.83. Removal of a vnut-renny ring of the bearing of differential


Fig. 3.84. Removal of the back bearing from the leading gear wheel


Fig. 3.85. Removal of the forward bearing from the leading gear wheel


Replace the bearings having wear. If bearings and details interfaced to them do not demand replacement, then do not make a vypressovka of rings of bearings. Of external rings of bearings (fig. 3.82) of differential from a case and a cover and removal of internal rings (fig. 3.83) of these bearings you make Vypressovka devices. Removal of back and forward bearings of the leading gear wheel is shown in fig. 3.84 and 3.85. An end face of a neck on which напрессован the back bearing, раскернен, therefore, it you make a vypressovka only for replacement. When dismantling the bridge internal and external rings of bearings of differential and not a razukomplektovyvayta conducting gear wheels, and at assembly the bearings which are not subject to replacement establish on former places.
The Maslootgonny ring has to have smooth end faces. If necessary to its proshlifuyta to thickness not less than 5 mm.
Cardan's flange. The flange end face interfaced to a maslootgonny ring has to be smooth. If necessary grind it to the size on height not less than 53 mm.
Bridge case. Remove all roughnesses and agnails from landing and adjacent surfaces of a case. Clean oil channels.
Differentials and half shafts. Replace persistent washers, axes of satellites, satellites, gear wheels of half shafts and a box of satellites with teases and strong wear. Replace satellites and semi-axial gear wheels completely. Replace a persistent washer of a semi-axial gear wheel if its thickness less than 1,2 mm. At wear of end faces of a box of satellites installation of the washers increased on thickness by 0,1 mm or by 0,2 mm is allowed.
At repair of back and forward bridges use these tab. 3.7 and 3.8.

Assembly and adjustment of knots of the back bridge
You make assembly of differential in the following order:
1. Before assembly of differential grease gear wheels of half shafts, satellites, persistent washers and axes of satellites with gearbox oil.
2. Establish persistent washers on necks of gear wheels of half shafts.
3. Establish a half shaft gear wheel with a persistent washer assembled in the left box of satellites.
4. Install satellites on an axis of a demountable crosspiece.

Fig. 3.86. Vypressovka external ring of the bearing of differential



5. Establish a demountable crosspiece (fig. 3.86) with satellites in the left box of satellites.

Fig. 3.87. Installation of boxes of satellites on tags



6. Establish a half shaft gear wheel with a persistent washer assembled in the right box of satellites. Holding a half shaft gear wheel, install the right cup of satellites on left so that tags (fig. 3.87) (serial numbers) of both cups were combined.
7. Connect half bolts and tighten them. Moment of an inhaling of 32-40 N · m (3,2–4,0 kgfs).
8. Establish the conducted gear wheel of the main transfer on a box of satellites, having combined openings under bolts. Establish bolts and tighten them. Moment of an inhaling of 98-137 N · m (10–14 kgfs · м).
At collected differential of a gear wheel of half shafts have to be turned by means of a shlitsevy mandrel from the effort no more than 59 N (6 kgfs) enclosed on the radius of 80 mm.
 You make adjustment of bearings of differential (in case of their replacement) in the following order:

Fig. 3.88. Preliminary nap-ressovka of vnut-renny rings of bearings diff-rentsiala



1. Napressuyte internal rings of bearings (fig. 3.88) of differential on necks of collected differential so that between end faces of a box of satellites and end faces of internal rings of bearings there was a gap of 3,5-4,0 mm.

Fig. 3.89. Prikatka rollers of bearings of differential



2. Establish differential assembled in a case, then laying and a cover of a case and, turning a cover for a casing, a prikatayta bearings so that rollers reached the correct position (fig. 3.89). Then bolts and nuts evenly connect a cover to a case.

Fig. 3.90. Measurements of gaps at adjustment of bearings of differential


Fig. 3.91. Gaps of A and A1 between end faces of internal rings of bearings and boxes of satellites


3. Again turn off bolts, carefully uncover, take out differential from a case and the probe measure gaps of A and A1 (fig. 3.90 and 3.91) between end faces of internal rings of bearings and boxes of satellites.
4. Pick up a package of laying by thickness calculated by a formula:
s = And + A1 + 0,1,
where: s – thickness of a package of laying, mm;
And yes A1 – gaps between end faces of internal rings of bearings and a box of satellites, mm;
0,1 – a constant (for providing a preliminary tightness), mm.
5. Remove internal rings of bearings of differential. Halve the picked-up package of laying approximately. Establish laying on necks of a box of satellites and a napressuyta internal rings of bearings against the stop.
 You make assembly and adjustment of bearings of the leading gear wheel in the following order:

Fig. 3.92. Kerneniye a shaft end face after napressovki the bearing: And – the place kerneniya


Fig. 3.93. Installation of the expansion plug and adjusting laying of the forward bearing of the leading gear wheel


1. Napressuyte bearings on the leading gear wheel. After a napressovka of the back basic bearing with cylindrical rollers you raskernit an end face of a shaft on which it напрессован (fig. 3.92). The expansion plug (fig. 3.93) and adjusting laying of the forward bearing (two-row conic) of the leading gear wheel have between internal rings.
2. Establish an adjusting ring 5 (see fig. 3.79) the leading gear wheel 9 (since 1991 is not established).

Fig. 3.94. Check of an inhaling of bearings of the leading gear wheel



3. Press the leading gear wheel assembled with bearings in a case against the stop and adjust a preliminary tightness of the forward bearing, changing thickness of a package of laying 8 and an inhaling of a nut 7 to the full. At the same time a maslootgonny ring 6 and a flange have to be established on a gear wheel shaft, and the forward bearing has to be uncovered that friction of a cuff about a flange did not influence indications of measurements. For reduction of a tightness add laying, for increase – remove. At the correct adjustment the axial gap has to be absent, and the spring dynamometer has to show effort of 15-30 N (1,5–3 kgfs) for the earned extra bearings and 20–35 N (2,0–3,5 kgfs) for new bearings at a gear wheel provorachivaniye for an opening in a flange (fig. 3.94).
4. After the end of adjustment, having removed a flange, establish laying and a cover of the forward bearing of the leading gear wheel. Fix a cover by bolts. Put a flange, tighten a nut 7 (see fig. 3.79) and a zashplintuyta. Moment of an inhaling of 167-206 N · m (17–21 kgfs · м).
 You make adjustment of a side gap and the provision of gear wheels of the main transfer after adjustment of bearings of the leading gear wheel and differential in the following order:
1. Establish in a case differential with the adjusted bearings assembled. Establish laying on the case socket plane with a cover. Establish a cover of a case and fix by bolts.

Fig. 3.95. Check of a side gap in gearing of gear wheels of the main transfer



2. Measure a side gap between teeths of the leader and conducted gear wheels which has to be 0,2–0,6 mm. You make measurement on a flange of the leading gear wheel on the radius of 40 mm (fig. 3.95).
Side gap regulate shift of laying 3 (see fig. 3.79) on the one hand differential boxes on another. If you remove laying from the conducted gear wheel, then the gap in gearing increases if you add, the gap decreases. Rearrange laying, without changing their quantity as it will break a tightness of bearings of differential.

Fig. 3.96. Spot of contact of gear wheels of the main transfer: I – party of the forward course; II – hundred-rona a backing; 1 – the correct contact in gearing of gear wheels when checking under small loading; 2 – contact at tooth top (for correction it is necessary to move the leading gear wheel by conducted); 3 – contact on a tooth root (for correction it is necessary to remove the leading gear wheel from conducted); 4 – contact on the narrow end of tooth (for correction it is necessary to remove the conducted gear wheel from the leader); 5 – contact on the wide end of tooth (for correction it is necessary to move the conducted gear wheel to the leader)



3. On the bridges having an adjusting ring 5 (see fig. 3.79), check gearing of gear wheels on a contact spot. For this purpose paint teeths of the conducted gear wheel paint. Consider that very liquid paint spreads, and too dense – it is not squeezed out of intervals between teeths. Then by means of half shafts brake the conducted gear wheel, and the leader rotate in both directions until the accurate spot of contact is designated. In fig. 3.96 typical provisions of a spot of contact on teeths of the conducted gear wheel and ways of elimination of the wrong contact are shown. You make movement of the leading gear wheel installation of an adjusting ring 5 (see fig. 3.79) other thickness. You make movement of the conducted gear wheel shift of laying of 3 bearings of differential.

Note
You make the specified check of gearing of gear wheels also on bridges with final drives.

 Assembly of the back bridge
You make assembly of the back bridge after adjustment of gearing of gear wheels in the following order:

Fig. 3.97. Measurement of a gap between a cover of the bearing and a case for selection of laying


1. Install a package of laying between an end face of a cover of the forward bearing of the leading gear wheel and a case. Thickness of a package has to be 1,3 times more than a gap (fig. 3.97) between end faces of a cover and a case. If necessary increase thickness of a package by 1,4 times.
2. Establish a cover of the forward bearing of the leading gear wheel with a cuff assembled and fix by bolts.
3. Establish a flange and a washer. Tighten a nut 7 (see fig. 3.79) to the full so that cuts in it coincided with openings in a shaft of a gear wheel and a zashplintuyta. The moment of an inhaling of 167 - 206 N · m (17–21 kgfs · м). Do not turn off a nut for coincidence of a groove and an opening under the forelock.
4. Establish differential with the conducted gear wheel and bearings assembled in a bridge case.
5. Establish laying between a case and a cover.
6. Establish a case cover so that both pillows of springs were in the top part of the bridge. Connect a cover and a case by means of bolts and nuts.
7. Turning the leading gear wheel, check lack of jamming or zadevaniye in the collected bridge. After assembly of the bridge check its heating during the movement of the car. If the case strongly heats up (over 90 °C), check correctness of adjustment of bearings.