Steering - Power Rack & Pinion Gear Service Information
89buick08Bulletin 89-3-17
Date May, '89
Ref. No. 89-138-3
Corp. Ref. No. 973203
SUBJECT: POWER RACK AND PINION GEAR SERVICE INFORMATION
MODELS AFFECTED: ALL 1980 THRU 1989 MODELS
In the interest of ease of repair, cost effectiveness and improved customer satisfaction, it has been decided that certain internal service parts and kits for power rack and pinion steering gears are being discontinued and will not be available from GM Service Parts Operations after current stock is exhausted.
FIGURE 1:
SERVICE PARTS AVAILABILITY INFORMATION
The only internal service parts/kits which will be available in the future are some seal/bearing kits used on the valve body (spool valve) and/or the valve body shaft, and under those conditions in which "Temporary Reduction of Power Steering Assist When Cold" occurs, the use of seal service kit (split ring) part 26010340 is advised. These seal kits will continue to be offered through General Motors Service Parts Operations. See Figure 1
FIGURE 2:
When the stock of a dealer-ordered service part or kit is exhausted, the dealer will be advised that the service part/kit is no longer serviced separately. If internal parts beyond these kits (see below) are required, because of problems unrelated to reduced assist when cold, the use of a service gear kit (partial) is advised. These partial service gear kits per specified application will continue to be available through General Motors Service Parts Operation. See Figure 2.
FIGURE 3:
FIGURE 4:
AVAILABLE INTERNAL SERVICE KITS
Part Number Description
26010340 Seal Service Kit (Split Ring) For Use
on 1980-1988 Models w/Aluminum Hsgs. Only
26012606 Brg Asm Service Kit, W/Seals
26012607 Brg Asm Service Kit, W/Seals
26012608 Brg Asm Service Kit, W/Seals
External service parts (boots, inner and outer tie rods, cylinder lines, adjuster plug lock nut) will continue to be available as service parts (see list included). See Figures 3 and 4.
The reason for discontinuing some internal service kits/parts is ease of repair and customer satisfaction. Analysis has shown that internal overhaul of certain component parts may not be as reliable and may be more costly to the customer. It has become more cost effective to install a short gear assembly than to perform internal repairs except in cases of reduced assist when cold, when installing the seal service kit for valve bore wear.
Analysis also has shown that leaks at the bulkhead seal, rack seal or piston seal when serviced are most often a temporary fix due to damage to other internal parts. Therefore, the replacement of these parts is not recommended. As a result, the sales of these parts have decreased to the point where it is no longer viable to maintain these parts for service, and the installation of a new or rebuilt "short" gear assembly is recommended.
SPECIAL POLICY BULLETIN Temporary Reduction of Power Steering Assist When Cold
The special policy is only intended to address customer comments of reduced power steering assist when cold which are caused by valve bore wear on vehicles equipped with aluminum housing steering gears. The "split ring" seal service kit (part number 26010340) will continue to be available, and should be the first procedure utilized to repair the reduced assist cold condition on aluminum housing steering gears, whether or not the vehicle is covered by the special policy. The "split-ring" kit has proven to be effective in cases of reduced assist cold, and should be used as the first avenue of repair on all reduced assist cold cases involving aluminum housing steering gears. If the "split-ring" kit does not correct the reduced assist cold condition, a "short" gear may be necessary, but must have prior Zone/Branch approval. THE SERVICE PARTS/KITS THAT ARE BEING DISCONTINUED SHOULD HAVE NO EFFECT ON THE RATE OF GEAR REPLACEMENT OF VEHICLES COVERED UNDER THE SPECIAL POLICY.
NOTICE: The "split ring" kit is not intended for use on vehicles equipped with cast iron valve housing steering gears. On steering gears with cast iron valve housings, no significant valve bore wear will occur, and installation of the "split-ring" kit will not improve steering performance.
UNNECESSARY REPLACEMENT OF POWER STEERING GEAR ASSEMBLIES
Stiff Steerinq After Cold Start In Very Cold Weather (Gears With Cast Iron Valve Housing).
Customers may comment on momentary stiff steering when the vehicle is first started in very cold weather (+10 degrees F or colder). This condition may be related to power steering cooler lines which are quite long on some vehicles.
This condition improves noticeably as the power steering fluid circulates thru the steering system. This will occur after a brief vehicle warm-up, or after two or three cycles of lock-to-lock steering wheel turns. This condition is due to the power steering system having to push very cold fluid thru the steering hydraulic system, including the cooler line. Power steering cooler lines are quite long on some vehicles. This condition may be compared to stiff shifting manual transmissions after cold starts in very cold weather.
NOTICE: This condition should not be diagnosed as reduced power steering assist when cold due to valve bore wear. On steering gears with cast iron valve housings, no significant valve bore wear will occur, and installation of the split ring kit will not improve steering performance.
Power Steering Fluid In Boots
Some power steering gear assemblies are being replaced unnecessarily when a small amount of power steering fluid is found in the boots. Small amounts of power steering fluid in the boots should not lead to gear replacement unless the customer has had to add power steering fluid to the system on a regular basis and/or has commented about external leakage of fluid.
If a customer has commented about having to add fluid and/or external leakage of power steering fluid, there should be a substantial amount of fluid in the boots. This condition would indicate that the steering gear should be replaced.
NOTICE: When adding fluid or making complete fluid change, always use GM power steering fluid, part number 1050017 quart, or 1052884 pint (or equivalent meeting GM Spec 9985010). Failure to use the proper fluid may cause leaks and may damage hoses and seals. The use of any form of Automatic Transmission Fluid is not recommended.
Looseness at Pinion Pin (See Special Policy Bulletin - Temporary Reduction of Power Steering Assist When Cold)
Some power steering gear assemblies are being replaced unnecessarily due to mis-diagnosis of pinion pin looseness. The pinion drive pin is designed with a small amount of clearance to the spool valve hole. As a result, a small amount of movement can be felt when the pinion-valve assembly is examined.
The drive pin should be carefully examined for damage under sufficient lighting conditions. If the pin is found to be broken, then a service "short" gear assembly must be installed in the vehicle.
If you have any questions on these issues, contact your zone service representative for clarification.