Power Steering - Temporary Lack of Assist When Cold
83saab02SUBJECT:
TEMPORARY LACK OF ASSIST WHEN COLD, 900 POWER STEERING
ISSUE: 04/83-624
FILE IN S.I. MANUAL:
VOLUME: I
SECTION: 6
PAGE: 19
Occasionally a complaint of temporary high steering effort immediately after cold start is heard concerning an older 900. The reason for this temporary lack of power assist is that the spool valve seal rings wear grooves in the housing bore. These seals shrink slightly at low temperatures and may not seal well enough until the hydraulic fluid begins to warm up. The period of no assist is related to the ambient temperature and degree of wear. (Green seals introduced as from model year 1982 will give decreased wear.)
The seals can be made to function properly when cold by diagonally slitting them thereby allowing them to conform to the housing bore as a piston ring conforms to an engine cylinder wall. Slitting and reusing the original seals this way is preferred over using new seals which may not fit the worn grooves precisely. This modification is effective even if the rings have worn rather deep grooves in the bore, thus it is usually not necessary to replace the rack assembly.
The repair procedure is as follows:
1. Remove the steering gear from the car per 900 Service Manual, Sec. 6.
2. Remove the spool valve from the housing (see 900 Service Manual, Sec. 6, P. 644-6, -7 and -8).
3. Loosen the four seal rings one at a time from their slots by "pushing them forward" with your fingers. Insert a feeler gauge or other thin object behind the ring.
4. Cut each ring diagonally with a sharp razor blade. Press the blade through the ring - do not use a sawing motion. The cut should be angled so that it is 5 to 7 mm long (1/4").
5. Carefully reinstall the valve in the steering gear housing using guide tool 02-94-066. DO NOT TRY TO HONE THE BORE OR RADIUS THE EDGES OF THE GROOVES. Center the rack and index the spool valve as per Sec. 6, P. 644-13.
6. Install a new pinion seal and dust protector.
7. Install steering gear in car and test function.
NOTE: Two special tools that help greatly are:
02-94-066 Pinion & Valve Assembly Teflon Ring Protector J 33057 02-94-025 Pinion Shaft Seal Protector J 29810
J 33057 acts as a seal ring compressor and guide during installation while J 29810 protects the lip of the shaft seal from damage on the sharp edges of the pinion shaft during assembly. (J = Kent-Moore no.)