Carraro front axle - Bearing and transmission shaft

The tractors are fitted with a fixed Carraro front axle. Drive is transmitted from the front axle clutch located in the rear axle via a transmission shaft. On 6-cylinder tractor engine models, the transmission shaft has a universal joint and the front axle pivot is raised. The shaft is divided into two sections. The section linked to the 4WD unit by a sleeve is fixed. 

The front part of the tractor transmission shaft has a universal joint, allowing the axle to oscillate on its raised pin. The two sections of the transmission shaft are linked by a castellated nut (11) and supported by a bearing (6) at gearbox level. The front frame supports the front axle pivot. The pivot front bearing is removable on all models, while the rear bearing is part of the front frame assembly.

Parts list Carraro 20.19 front axle
(1) Straight shaft (2) Guard (2A) Guard (3) Sleeve (4) Screw (5) Central bearing (6) Bearing (7) Dust seal nut (8) Spider (9) Shaft (10) Sleeve (11) Castellated locknut (12) Front frame (13) Chamfered washer (14) Washer (15) Front bearing (16) Seal (17) Ring (18) Ring (19) Plug
(20) Circlip (21) Screw (22) Front axle (23) Grease nipple (24) Union (25) Lubrication pipe (26) Flanges (27) Screw

Disassembling and reassembling the 4WD transmission shafts and the universal joint spiders

Disassembling the universal joint shaft 
Chock the rear wheels and apply the hand brake.
Remove the guards (2)(2A). Unscrew the dust seal nut (7).
Remove the screws (27) and the flanges (26).
Move the universal joint shaft (9) and spider (8) assembly away from the drive pinion carrier. Remove the shaft. If there is not enough room to push the universal joint shaft backwards for removal, disassemble the central bearing and the straight shaft (1). The spiders are replaceable. They are listed in the parts book.

CHECKS: If the spiders need to be replaced, carefully check the condition of the end clevises where the spider catches are located. Remove any traces of impact or sharp edges. Thoroughly clean the groove of each circlip. After assembly, check that the circlips are properly positioned in their respective grooves.
If necessary, and to facilitate mounting of the universal joint shaft on the drive pinion carrier, raise the front wheels using a jack with sufficient lifting capacity, positioned along the axis of the axle housing.
Replace the dust seal nut (7). Use a makeshift tapered tool to refit the dust seal nut (7) on the shaft (1).
Smear the front splines of the straight shaft with molybdenum sulphide grease or equivalent. Refit the universal joint shaft (9).
Attach the front spider (8) to the plate of the drive pinion carrier using the flanges (26) and washer-head screws (27) that have been lightly smeared with Loctite 241 or equivalent and tightened to a torque of 34-41 Nm.
Moderately tighten the dust seal nut (7).
Using a grease gun, lubricate the sleeve (10) and refit the guards (2) and (2A).

Disassembling the straight shaft and bearing 
Remove the guards (2) (2A) and the universal joint shaft assembly.
Remove the screw (4) and slide the sleeve (3) towards the front of the straight shaft. Remove the central bearing (5), bearing (6) and straight shaft (1) assembly.

Separate the support (5) from the bearing (6). Unscrew the castellated nut (11) using a suitable wrench. Remove the bearing from the straight shaft.

Reassembling the straight shaft and bearing 
Check the parts. Replace those that are defective.
Install bearing (6) on the straight shaft with the offset turned rearwards. Tighten the nut with a suitable wrench.
Assemble the support (5) on the bearing (6). Tighten the screws.
Reinstall the central bearing, bearing (6) and straight shaft (1) assembly.
Smear the rear splines of the straight shaft (1) with molybdenum sulphide grease or equivalent.
Slide the sleeve (3) towards the rear of the straight shaft. Refit the screw (4). Replace it if it is in a poor condition. Reinstall the universal joint shaft assembly. Reinstall the guards (2) (2A).

Removing and install the bearing support and front axle

Remove the 45 kg front weights (if fitted). Immobilise the tractor. Apply the hand brake. Place safety chocks on either side of the rear wheels

Some tractors may be fitted with a front power take-off. In this case, it will be necessary to remove it in order to separate the front axle from the frame (12). In certain conditions, the centre weight (1) of 100 kg may obstruct the removal of the bearing support. For this configuration, strip out the internal parts at the lower part of the grille to gain access to the weight. Take out the central M20 screw (2) and lift the weight slightly using a suitable lifting tool to release it from the support.

Removing the support (15) and the front axle. Remove the guards (2) (2A).
Raise the tractor along the axis of the front axle housing using a jack with sufficient lifting capacity. Remove the front wheels.
Mark the steering hoses connection and detach them from the ram.
Disconnect the front differential lock control hose.
Sling the front axle using suitable strapsRemove the screws (21).
Pull the front axle assembly complete with bearing support (15) forwards along the axis of the axle beam (position 1) and remove the front axle (position 2). Note the features, order and position of the washers (13) (14) and the direction of the chamfers and remove them.

Check point
Clean all components and check the condition of:
- the pivot pin at each end
- the washers (13) (14)
- the friction rings (17) (18)
- the seal (16).
Slide the washers (13) (14) lightly smeared with bearing grease onto the front and rear ends of the pivot pin. Position the washers in the order.
Sling the front axle. Moderately lubricate the ends of the pivot pin and Install the support (15) at the front of the pivot pin. Before refitting the front axle assembly, check that there is no excess grease in the cavity of the second axle beam pivot on the front frame. When refitting the front axle assembly, any such excess grease will be compressed, and may hinder insertion of the pivot pin into its bearing. Reinstall the front axle and support (15) assembly.
Push the assembly hard until it comes into contact with the second axle beam pivot. Thrust the support (15) against the front axle assembly (22) to eliminate the clearance between supports and axle housing as much as possible. Install the screws lightly smeared with Loctite 270 or equivalent and tighten to a torque of 520 - 640 Nm.

Check point
Check that the front face of the pivot pin is almost level with the front edge "F" of the bearing support (15).

Visually check for the presence of the grease nipple on the left-hand side of the front frame (12) (second axle beam pivot) and on the support (15) (first axle beam pivot)Reconnect the hoses (using marks made during disassembly):
- of the steering ram
- of the front differential lock
Reinstall the wheels. Remove the axle stand and take away the jack. Tighten the nuts to a torque of 640 - 680 Nm.
Reinstall the centre weight. Tighten the central screw to a torque of 100-150 Nm and secure the front weights (depending on equipment fitted).
Reinstall the universal joint shaft and the guards.
Remove the safety chocks and release the hand brake.
Using a grease gun, lubricate the friction rings (17) (18) of the axle beam pivots.

Replacing the friction rings and seal

Disassembling the front bearing
Only remove the bearing support (15). Extract and discard the ring (17). Drive out and discard the seal (16).

Reassembling the front bearing

Clean and check all components. Replace those that are defective. Check that the lubrication lines in the support are not blocked.

Using a press and a suitable fixture, Install the seal (16), positioned correctly, and the ring (17) level with face "F" of the support (15), with the lubrication port "T" connecting with the line.

To work on the ring (18) of the second axle beam pivot, the first axle beam pivot and the front axle must be removed.

Disassembling the rear bearing 
Drive out the ring (18) using a makeshift tool. The circlip (20) and the plug (19) are not considered to be wearing parts. It is therefore unlikely that they will need replacing.

Reassembling the rear bearing 

Using a makeshift fitting drift, Install the ring (18) onto the frame (12) level with the chamfer "C".