CHF 4.55
CHF 4.55
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Available: 5.0 Units
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Product information:
New Holland Case
Brake master cylinder piston seal (ATAY)
DESCRIPTION OF THE PROBLEM
The brake master cylinders on Case IH Farmall Stage III (JX) tractors and New Holland TD5000 Series tractors are from two different suppliers: ATAY and BOSCH. Only BOSCH branded master cylinders are available from LT and no internal replacement parts.
Since September 2008 (from serial number Z8JP51991 or Z8JN51991) all standard Farmall tractors of stage III (JX) and all tractors of the TD5000 series are equipped with the master cylinder of the ATAY brand. Prior to September 2008, all Farmall Stage III (JX) tractors and all TD5000 Series tractors were equipped with the BOSCH brand master cylinder.
The ATAY and BOSCH master cylinders are listed under the same part number. The two master cylinders can be recognised by the following physical characteristics:
The body of the ATAY brand master cylinder is silver in colour.
The body of the BOSCH master cylinder is black in colour.
An improved piston seal (part number 84336253) is available for the ATAY brake master cylinder. This seal is made from a more durable material that offers greater wear resistance.
The ATAY brand brake master cylinder with the improved piston seal was introduced into production at serial number ZAJP51657 (CIH) or ZAJN51656 (NH).
If the brakes do not perform as expected, perform the following procedures
1. ensure that the brakes have been adjusted correctly.
2. bleed the brake system to ensure that there is no air in the system. This includes bleeding the front axle brakes and the trailer brake valve, if fitted.
3. compare the operation of the individual brake pedals, i.e. pedal height adjustment and pedal travel as well as height when depressed.
4 Repeat the test with the brake pedals locked together.
5. if the brakes do not behave as expected, i.e. if the pedal feel is spongy or the pedal sinks to the floor when depressed, and if both pedals are affected when locked together, the master cylinder piston seal may be defective: To determine if a master cylinder is defective, disconnect the brake lines from the master cylinders to the tractor brake cylinders and plug them with a suitable plug. Then repeat steps 3 and 4.
If the master cylinder then functions properly, the cause is not a defect in the master cylinder piston seal, but is related to a defect normally associated with the loss of brake fluid, i.e. leakage of the piston seal of the rear brake cylinder (visible external leakage) or leakage of the seals of the front brake piston (internal leakage).
If the master cylinder still does not function properly, the cause is a defect in the master cylinder piston seal:
- On machines equipped with ATAY brand brake master cylinders, only the master piston seal can be replaced.
- On machines equipped with BOSCH brand brake master cylinders, the entire assembly must be replaced.
ADDITIONAL INFORMATION
On Farmall Stage III (JX) and TD5000 Series tractors, two brake master cylinders connected by an equalising pipe are used to maintain equal oil pressure between the two cylinders and provide equal braking force when both brake pedals are depressed. When one of the brakes is applied to assist turning, the activated brake master cylinder only applies the right or left brake on the rear axle. Pressure equalisation with the inactive brake is prevented by seals on the non-activated master cylinder.
However, if the inactive pedal is depressed slightly as a result of incorrect adjustment, jamming or operation of the brake pedal by the driver, the pressure equalisation connection in the inactive master cylinder is opened. In this case, the oil from the actuated brake flows through the equalising tube, the inactive cylinder and to the reservoir; the actuated brake pedal then slowly sinks to the floor, so that no braking effect occurs. Even with the correct setting, it is still possible to depress one brake pedal slightly and move the other pedal to the floor by pumping or tapping it. This is a normal feature of most tandem master cylinder designs used on construction machinery and agricultural tractors.
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