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Skoda Workshop Service and Repair Manuals

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Removing and Installing parts of the ABS System on the front and rear axle > < Brake servo unit/master brake cylinder, hydraulic control unit ABS/EDL/TCS/MSR/ESP BOSCH 5.7

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Repairing the hydraulic control unit ABS/EDL and ABS/EDL/TCS/MSR BOSCH 5.3
Repairing the hydraulic control unit ABS/EDL and ABS/EDL/TCS/MSR BOSCH 5.3
  Note
t  The sealing surface on the hydraulic control unit must be clean and undamaged. It must never be reworked, (e.g. with files, scrapers etc.). If necessary replace the hydraulic unit.
t  The gasket on the control unit must not be removed, it cannot be replaced.
t  The screws (inner Torx T20) of the hydraulic unit/control unit must be replaced after each removal. Use the screws included in the parts kit. Compare the length of the screws removed with those in the parts kit (long and short screws, the difference being approx. 1.5 mm) and determine the correct length of the screws. Never screw long screws into hydraulic control units which have threaded bores for short screws. Tightening must occur in the prescribed sequence and in steps.
t  If the control unit is being replaced tentatively tighten the fixing screws only slightly Tighten the screws to the specified torque once the control unit is correctly positioned on the hydraulic unit.
   
t  Maximum 5 tightening procedures (hydraulic unit) may be carried out throughout the entire life of the hydraulic control unit. Pay attention to the colour markings (approx. 3 mm wide red lines) on the hydraulic control unit. Replace the complete hydraulic unit if more than 5 tightening procedures have been performed (-arrow- area for colour markings).
t  The threads in the hydraulic unit for securing the control unit must not be rethreaded. If the thread is damaged (screws are hard to tighten by hand or they cannot be tightened to the prescribed torque) replace the hydraulic control unit.
t  Blowing out of the control unit or the hydraulic unit with compressed air to secure an oily or aqueous film on and between the valve domes or the solenoid coils is not permissible! Only use moisture-free and oil-free compressed air, e.g. from a spray. Cleaning with hydrocarbon solvents is not allowed.
t  If the hydraulic control unit is open protect the valve domes, solenoid coils, contact springs against damage and soiling.
t  Repair is only possible with the hydraulic control unit removed.
t  Disassembly and assembly of the hydraulic control unit is described on an ABS/EDL BOSCH 5.3 unit. The procedure for the ABS/EDL/TCS/MSR BOSCH 5.3 unit is identical.
–  Remove the hydraulic control unit → Chapter
Disassembling the hydraulic control unit
  S45-0133
Hydraulic unit -N55- with return flow pump -V39- (-a-):
t  Hydraulic unit: The valve block includes the control valves.
t  Do not separate the return flow pump -V39- from the hydraulic unit -N55 -.
ABS control unit -J104 - (-b-)
  S45-0137
–  Release inner Torx screws T20 -Postions 1 through to 6-.
  S45-0134
–  Raise the latch spring on the 2 pin connection and remove the plug arrow -A-.
–  Unclip the cables of the plug/return flow pump arrow -B-.
  S45-0135
When tightening the control unit -b- of the hydraulic unit -a- make sure the valve domes -1- are not tilted along with the solenoid coils -2-.
3 - Gasket made of silicone
The gasket is injected and cannot be replaced. The control unit should not be reinstalled if the seal is damaged.
–  Cover the solenoid coils of the control unit.
–  Protect the valve dome from damage and contaminants. Do not use fluffing cloths or a transport protection of an already installed spare part hydraulic pump. This is a requirement for possible guarantee claims.
Assembling the hydraulic control unit
–  Inspect the sealing surface on the hydraulic unit for soiling, if necessary clean with white spirits and a non-fluffing paper or linen cloth.
–  If an oily or aqueous film appears on the surface of the hydraulic unit, clean with white spirits and a non-fluffing paper or linen cloth.
–  If there is a considerable oily and aqueous film between the valves use moisture-free and oil-free compressed air to blow it out.
–  If damage is noticed on the hydraulic unit (e.g. scoring or scratching etc.) near the seal, replace the hydraulic unit.
–  Check the gasket of the control unit for tears, roughened surface, elasticity (the gasket must not be hard), notches and a protrusion of 0.1 mm.
   The protrusion is the distance between the lugs in the housing of the control unit and the top side of the gasket.
   The control unit should not be reinstalled if there is anything wrong with the gasket. It is not possible to replace the gasket.
–  Compare the length of the screws removed with those in the parts kit (long and short screws, the difference being approx. 15 mm) and determine the correct length of the screws. Never screw long screws into hydraulic control units which have threaded bores for short screws.
  Note
When assembling the control unit and the hydraulic unit make sure the valve domes of the hydraulic unit do not tilt along with the solenoid coils of the control unit.
–  Place the control unit on the hydraulic unit and guide the solenoid coils over the valves by exerting a slight pressure. While doing so center the control unit relatively to the hydraulic unit.
–  Press by hand on the control unit until it fixes in place with the two centre screws.
  Note
t  Only use new inner Torx screws from the parts kit. Make sure you use screws of the correct length.
t  Screw on the hydraulic unit and the control unit in the prescribed sequence and in steps. Tightness will not be guaranteed if this is not observed.
t  When screwing together make sure the left and right gap between the control unit and the hydraulic unit is always the same.
  S45-0136
–  First screw in the inner Torx screws and tighten them by hand in the alternating sequence 1 - 2, 3 - 4, 5 - 6.
–  Tighten all inner Torx screws in the alternating sequence 1 - 2, 3 - 4, 5 - 6 to the prescribed tightening torque.
  S45-0134
–  Mark each fitting of the hydraulic unit with the control unit in the area -arrow- with a permanent red colour mark approx. 3 mm wide.
–  Insert a 2-pin plug into the control unit and secure using the latch spring.
   The snapping in to place of the latch spring must be audible.
–  Clip the cables of the plug and the return flow pump into the holder.
–  Install hydraulic control unit with bracket → Chapter
Continued for all vehicles
  S45-0133
Tightening torque:
Screw the control unit to the hydraulic unit
t  Use new screws!
t  Make sure you use screws of the correct length!
2.6°Nm

   

Removing and Installing parts of the ABS System on the front and rear axle > < Brake servo unit/master brake cylinder, hydraulic control unit ABS/EDL/TCS/MSR/ESP BOSCH 5.7