{"model":"mk3","model_name":"MK3 Supra","vehicle":"Toyota Supra A70 (1986.5–1992, 7M-GE / 7M-GTE)","document":"Repair Manual","section":"SR","section_name":"Steering","page":36,"pages_in_section":96,"title":"Power Steering Description","section_header":"Steering — Power Steering (Description)","ocr_text":"POWER STEERING\nDescription\n\nPRINCIPLES OF POWER STEERING\n\nPower steering is one type of hydraulic device for\nutilizing engine power to reduce steering effort.\nConsequently, the engine is used to drive a pump\nto develop fluid pressure. This pressure is used to\na piston within the power cylinder so that the piston\nwill move by rack effort. The amount of this as-\nsistance depends on the extent of pressure acting\non the piston. Therefore, if more steering force is\nrequired, the pressure must be raised. The varia-\ntion in the fluid pressure is accomplished by a con-\ntrol valve which is linked to the intermediate shaft\nand the steering main shaft.\n\nReservoir Tank\nVane Pump\nRack\nMain Shaft\nIntermediate\nShaft\nGear Housing\n\nSR31/6\n\nNEUTRAL (STRAIGHT-AHEAD) POSITION\n\nFluid from the pump is sent to the control valve.\nIf the control valve is in the neutral position, all the\nfluid will flow through the control valve into the\nreservoir tank back to the pump. At this time, hardly\nany pressure is created and because the pressure\non the cylinder piston is equal on both sides, the\npiston will not move in either direction.\n\nPUMP\nControl\nValve\nRelief Port\nPower Cylinder\nCylinder Piston\n\nSR7390\n\nWHEN TURNING\n\nWhen the steering main shaft is turned in either\ndirection, the control valve also moves, closing one\nof the fluid passages. The other passage then opens\nwider, causing a change in fluid flow volume and,\nat the same time, pressure on the cylinder. Actual-\nly, a pressure difference occurs between both sides\nof the cylinder, and the piston moves in the direction\nof the lower pressure so that the fluid in the cylinder\nis forced back to the pump through the control\nvalve.\n\nPUMP\n\nSR7391","image":"https://tsrm.sasquatchvc.com/images/mk3/SR/SR_036.png","url":"https://tsrm.sasquatchvc.com/mk3/tsrm/SR/36","prev":{"page":35,"url":"https://tsrm.sasquatchvc.com/mk3/tsrm/SR/35","api":"https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/35"},"next":{"page":37,"url":"https://tsrm.sasquatchvc.com/mk3/tsrm/SR/37","api":"https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/37"},"section_url":"https://tsrm.sasquatchvc.com/mk3/tsrm/SR","section_api_pages":["https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/1","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/2","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/3","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/4","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/5","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/6","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/7","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/8","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/9","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/10","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/11","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/12","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/13","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/14","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/15","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/16","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/17","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/18","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/19","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/20","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/21","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/22","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/23","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/24","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/25","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/26","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/27","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/28","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/29","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/30","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/31","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/32","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/33","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/34","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/35","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/36","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/37","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/38","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/39","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/40","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/41","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/42","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/43","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/44","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/45","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/46","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/47","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/48","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/49","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/50","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/51","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/52","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/53","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/54","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/55","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/56","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/57","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/58","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/59","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/60","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/61","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/62","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/63","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/64","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/65","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/66","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/67","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/68","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/69","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/70","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/71","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/72","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/73","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/74","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/75","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/76","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/77","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/78","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/79","https://tsrm.sasquatchvc.com/api/pages/mk3/tsrm/SR/80","https://tsrm.sasquatchvc.com/api/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transcript of a scanned Toyota factory manual page; verify critical values (torque specs, part numbers) against the image."}