FAQ Hydraulic auxiliary steering, steering assistance (power steering, Calconi)

[Joachim]

Basic parameters of the Jihostroj hydraulic pump (steering aid for Zetor 4911-7045):

- 80 bar max. operating pressure​

- 10 l/min and 80 bar at 1200 rpm of the engine​

- gear pump with 10 teeth per gear​

- turning right​

- ET no.:​

from 1970 5511-3950​

from 1882 7011-8300​

from 1987 7011-8320​

Later, from Zetor 5211 (from 1987 onwards), the pump was modified and given an output of 15 l/min at 100 bar operating pressure, which ensured noticeably better steering, especially at idle. This pump can also be installed in existing older systems.

ETH-Weisse.de, for example, also offers suitable steering hydraulic pumps, including one from Hylmet with the following data:

- 25 l/min (at 1600 rpm)​

- 100 bar operating pressure nominal, 120 bar maximum​

- turning right​

- 16 cc​

Location of the pump on the engine bulkhead:


Pump drive sprocket:


Hydraulic power steering tank to the right of the blue MANN air filter:


Power steering cylinder probably of identical construction or licensed construction from RCD Calconi:


Detailed shots of the control of the power steering cylinder via the mechanical steering gear of the Zetor, here Zetor 5011:



Repair or new purchase:

Spare parts for the original steering aids (there were/are 2 manufacturers and both variants differ slightly) as well as the repair of the complete steering aid cylinders and also complete retrofit kits based on the original design are at some spare parts stores online.​

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Replace the joint bearing at the rear end of the power steering cylinder:

The suitable spherical plain bearing is a GE20-UK or better a GE20-UK 2RS sealed on both sides to extend its durability.​

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This 2RS bearing does not replace the factory sealing rings and spacer rings, these must be reinstalled on all spherical plain bearing variants.​

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If the seat of the joint bearing in the short steering arm is already attacked, then it may be advantageous to dismantle the short steering arm from the long steering arm in order to heat the short steering arm and its bearing seat of the joint bearing and then let it cool down. The lever and especially the bearing seat shrink slightly further than before heating.​

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Then, after it has cooled down, the new spherical plain bearing can be reinserted with Loctide "Join Shaft Hub" and fixed using punch punches.​

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You can then reinstall the steering lever/steering arm and complete the steering again. Don't forget the two spacer sleeves and sealing rings on both sides of the spherical plain bearing. These should be supplied with good long-term grease as the spherical plain bearing is not lubricated.​

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Setting a new steering aid on the tractor:

Procedure for adjusting the auxiliary steering when it pulls to the right or left (in each case viewed in the direction of travel):​

1. Completely jack up the Zetor on the front axle so that both front wheels are in the air but can be fully steered in all directions.
2. Loosen the screw on the larger (rear) clamp of the rubber bellows and push it forward.
3. Loosen (do not remove!) the M8 nut of the clamping ring of the chrome-plated piston tube. You can now easily expand the clamping ring slightly with a slotted screwdriver if necessary.
4. Starting the engine and setting the nominal speed (2,200 rpm)
5. Wrap the chrome-plated piston tube with a piece of leather or several layers of fabric in order to be able to grip and turn the piston tube as far back as possible with pliers.
6. If the steering pulls to the right:
   1. Turn the piston tube downwards (looking at it from the side), i.e. further onto the thread of the slide housing.
   2. Now continue turning this slowly until the front wheels no longer “run away” to the right on their own.
   3. The front wheels should be kept in the straight-ahead position.
7. If the steering is to links draws:
   1. turn the piston tube upwards (looking at it from the side), i.e. further away from the thread of the slide housing.
   2. Now continue turning this slowly until the front wheels no longer "run away" to the left on their own.
   3. The front wheels should be kept in the straight-ahead position.
8. After adjusting, secure all loosened connections (clamp, locking ring of the rubber bellows)
9. If you haven't already done so, bleed the steering by slowly turning it several times up to the stops and holding it briefly.
10. unjack the tractor again

Complete conversion kits/spare parts for Zetor tractors where steering assistance was provided ex works:

Zetor spare parts dealer of your joice.​

Complete conversion kits for Zetor and other brands where steering assistance was not provided ex works:

www.AHS-Hydro.de​

www.thoni.de​