Fiat issued this 68-page cab and air conditioning service manual under factory publication number 603.54.245.00, and it applies to eleven 90 series wheeled tractors, from the 55-90 through the 180-90. Separate wiring diagrams trace the circuits for Comfort Cab, Supercomfort Cab and air conditioned Supercomfort Cab tractors, which makes this Fiat 100-90 service manual PDF useful whichever cab your tractor carries. Refrigerant charging, discharging and electronic leak testing run in order and finish at an air conditioner troubleshooting chart; other chapters handle cab removal, glass and door seal replacement, heater overhaul and compressor work. Charge the system with 1.7 kg of refrigerant. Maximum system pressure sits at 16 to 20 bar. If a crankshaft seal or electromagnetic clutch is on your parts order, the compressor chapter shows how each comes out and goes back in. Set that clutch gap to 0.4 to 0.8 mm and the front plate nut to 25 to 29 ft.lb, working from a bookmarked, searchable PDF.
What's Inside This Fiat 55-90 to 180-90 Manual
| System | Pages | Key Topics |
|---|---|---|
| General | 7-8 | Comfort Cab, Supercomfort Cab |
| Cab Versions | 9 | Comfort Cab, Heated and Ventilated Supercomfort Cab, Air Conditioned Supercomfort Cab, Paint Specification |
| Controls | 10-12 | Temperature Control Knob, Windshield Washer, Fan Control Switch, Windshield Wiper Switch, Temperature Control Lever, Air Conditioner on/Off |
| Air Conditioning System | 13-20 | Safety Precautions, Specification, Operation, Main Components, Repair Notes |
| Cab Removal and Installation | 21-26 | Cab Removal Together with Platform, Cab Installation Together with Platform, Removal and Installation of Cab Without Platform, Cab Removal and Installation Together with Platform |
| Body Repair | 27-34 | Rear Window Glass Replacement, Rear Window Hinge Replacement, Door Removal and Adjustment, Cab Glass Replacement, Door Seal Replacement, Headlining Removal and Installation |
| Heater and Fan Overhaul | 35-38 | On-Tractor Heating System Schematics, Heater Unit Removal and Installation, Heater System Line Removal and Installation, Comfort Cab |
| Air Conditioning System Charging and Discharging | 39-49 | Charging Station, System Filling, System Operation Check, Summary of System Filling Operations, Leakage Test Using Electronic Leak Detector, System Discharging, Trouble Shooting |
| Conditioner Overhaul | 50-52 | Air Conditioning System Schematics, Evaporator and Heater Unit Removal and Installation, Air Conditioning System Lines Removal and Installation |
| Compressor Maintenance and Overhaul | 53-62 | Compressor Filling and Oil Level Check, Electromagnetic Clutch Replacement, Crankshaft Seal Replacement, Valve Plate and Head Replacement, Drive Belt Installation and Tension Check |
| Electrical System | 63-65 | Wiring Diagram - Supercomfort Cab Tractors, Wiring Diagram - Air Conditioned Supercomfort Cab Tractors, Wiring Diagram - Comfort Cab Tractors |
| Service Tools | 66-68 | Wrench, Puller, Pliers, Striker and Guide Bushing, Protector, Remover, Tongs, Guide Pin |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| Air conditioning system maximum system pressure | 16 to 20 bar / 227 to 284 psi | p. 14 |
| Electromagnetic clutch gap | 0.4 to 0.8 mm (0.016 to 0.032 inch) | p. 54 |
| Front plate retaining nut torque | 3.5-4 kgm (25-29 ft.lb) | p. 57 |
| Refrigerant capacity | 1.7 kg | p. 14 |
| High pressure switch opening pressure | 20 bar | p. 14 |
| Low pressure switch opening pressure | 0.2 bar | p. 14 |
| Rear window hinge torque | 12-14 Nm | p. 27 |
| Door hinge inner screw torque | 29-34 Nm | p. 28 |
| 55-90, 60-90, 70-90, 80-90 | ||
| Compressor displacement (SD-508) | 138 cc | p. 14 |
| Compressor oil capacity (SD-508) | 175 cc | p. 14 |
| 90-90, 100-90, 115-90, 130-90, 140-90, 160-90, 180-90 | ||
| Compressor displacement (SD-510) | 161 cc | p. 14 |
| Compressor oil capacity (SD-510) | 135 cc | p. 14 |
Fiat 55-90 to 180-90 Common Problems This Manual Covers
Fiat 90 Series cab air conditioning gives insufficient cooling or no cooling from the vents
Connect the charging station gauges and run the system pressure test following the trouble shooting steps on page 48. Verify system pressure stays within 16 to 20 bar (227 to 284 psi) per page 14, and recharge with 1700 grams of refrigerant per page 42. Wear face and eye protection while charging (page 13), and discharge only in a ventilated area away from open flames (page 46).
Manual Section: Air Conditioning System Charging and Discharging p. 48AC compressor failure traced to the electromagnetic clutch, needing replacement and an air gap check
Replace the electromagnetic clutch following the compressor maintenance and overhaul procedure starting on page 53. Measure the clutch air gap against 0.4 to 0.8 mm (0.016 to 0.032 inch) as listed on page 54. Fit a new front plate retaining nut and torque it to 3.5-4 kgm (25-29 ft.lb) as page 57 specifies before running the compressor.
Manual Section: Compressor Maintenance and Overhaul p. 54Air conditioning system slowly losing refrigerant charge and needing a leak test before recharging
Test for leaks with an electronic leak detector following the leakage test in the charging and discharging section starting on page 39. Never loosen fittings or tamper with lines while the system is charged, as page 13 warns. Once the leak is repaired, evacuate the system with the vacuum pump and recharge with 1700 grams of refrigerant per page 42.
Manual Section: Air Conditioning System Charging and Discharging p. 39Cab door will not shut properly or door chatter is felt once it is shut
Slacken the lower striker on the cab and move it outwards if the door will not shut, or inwards if it chatters when closed, following page 28. Slacken the two upper striker retaining screws and adjust them the same way, then check the door closes cleanly. If the hinges were disturbed, torque the inner hinge screws to 29-34 Nm.
Manual Section: Body Repair p. 28Cab heater blowing cold air after cab reinstallation and refilling the cooling system
Refill the radiator with water and FIAT PARAFLU 11, then follow page 22: close the heater cock (blue sector), run at part throttle five to ten minutes, open it (red sector) and run at governed speed five minutes. Top up through the radiator at high revs. Check the heating system lines were not interchanged during installation, as page 24 warns.
Manual Section: Cab Removal and Installation p. 22Rear window glass hinge sealing rings not sealing after glass or hinge replacement
Replace the sealing rings whenever the glass comes off and lubricate the seals with FIAT PARAFLU 11 or soapy water, never oil or grease, per page 27. Tighten the inner hinge plate screws to 12-14 Nm using wrench 293512, then fit the glass and tighten upper screws first, followed by lower screws, to 24-29 Nm.
Manual Section: Body Repair p. 27Frequently Asked Questions
What is the correct torque for the rear window hinge retaining screws on the Fiat 55-90 to 180-90?
When installing the rear window hinge, the retaining screws must be tightened to a torque of 12-14 Nm (1.2-1.4 kgm, 8.8-10.3 ft.lb) using wrench 293512. p. 27
What is the correct belt yield for the compressor drive belt on 55-90 to 80-90 models?
For models 55-90, 60-90, 70-90, and 80-90, the belt yield should be 12-13 mm (0.47 to 0.51 in) when 8-10 kg (18-22 lb) of force is applied midway on the belt leg. p. 61
How much lubricating oil is required for a Sankyo SD-508 compressor?
The Sankyo SD-508 compressor is filled with 175 cc (170 ± 14 grams) of lubricating oil at the factory. p. 14
What is the procedure for checking the compressor oil level?
After running the compressor for 10 minutes at 1500 rpm and discharging the refrigerant, use indicator rod 293055 to measure the oil level. The correct level is determined by counting the number of divisions wet with oil, which varies based on the compressor installation angle. p. 53
What is the correct torque for the compressor head hold-down bolts on a Fiat 55-90 to 180-90?
After installing the head and gasket, the five head hold-down bolts must be tightened to 3-3.5 kgm (21.7-25.3 ft.lb) in the specified sequence. p. 60
How quickly can I access this Fiat 55-90 manual after buying?
You download the Service Manual yourself: 68 pages, searchable PDF, available immediately. Keep a copy on every device you use.
Am I free to print this Fiat 55-90 Service Manual?
Yes. Printing works from any reader and any printer, for your own shop use.
