This bulletin is prepared to supersede the previous Special Red Band Service Letter, Dealer #163 dated November 28, 1955, relative to power steering gear leakage. Recently a change was made in the master steering gear seal kit. These changes were made to simplify ordering and to make a more usable service kit.

The new master seal service kit Gr. 6.507 Part # 5685027 is composed of five (5) individually packaged service kits:

Kit No. 1 – Gr. 6.855 Part #5683796 Pitman Shaft Seal and Wiper Service Kit.
Kit No. 2 – Gr. 6.825 Part #5685028 End Cover Adapter and Valve Mounting Seal Service Kit.
Kit No. 3 – Gr. 6.524 Part #5685029 Worm, Side Cover and Valve Seal Service Kit.
Kit No. 4 – Gr. 6.822 Part #5684554 Nut, Lash Adjuster Seal.
Kit No. 5 – Gr. 6.806 Part #5684069 Housing End Plug Service Kit.

The seals contained in each kit may be seen in Fig. 64.

1956 Buick Steering Gear Master Seal Service Kit

1956 Buick Steering Gear Master Seal Service Kit

Each of these kits may be ordered separately since many times a leak will be encountered that will require the use of only one or two of the five kits. It is not intended that when the master seal kit is ordered that all the seal kits be used. Included in each master seal service kit there will be a drawing that will show the areas in which each of the five (5) individual seal kits will be used. At the present time the Parts Department has sufficient stock of the master seal kit; however, the individual kits which comprise the master kit are not yet available. It is suggested, therefore, that dealers first order the master seal kit for power steering leakage repairs; thereafter, order only those kits which are absolutely necessary to repair the unit.

With the adoption of the master seal kit, several service procedures have been altered. These procedures are outlined below:

Kit No. 1 – Gr. 6.855 Part #5683796 Pitman Shaft Seal and Wiper Service Kit.

If, upon inspection of the gear, it is found that oil leakage exists at the pitman shaft seal, the seal may be replaced without removing gear from car by performing the following:

  1. Remove starter splash pan, then disconnect pitman arm from gear.
  2. Thoroughly clean end of pitman shaft and housing, then tape splines on end of pitman shaft to insure that seal will not be cut by splines during disassembly and assembly. NOTE: Only one layer of tape should be used; an excessive amount of tape will not allow the seal to pass over it, due to the close tolerance between the seal and the pitman shaft.
  3. Remove pitman shaft seal retaining ring with No.3 Truarc pliers J-4245.
  4. Start engine and tum steering wheel to the right until oil pressure in the housing forces out the seal. Tum off engine. NOTE: Use suitable container to catch oil forced out of gear. This method of removing the pitman shaft seal is now recommended, as it eliminated the possibility of scoring the housing while attempting to pry it out.
  5. Inspect seal for damage to rubber covering on O.D. If the O.D. appears scored, inspect housing for burrs and remove before attempting new seal installation.
  6. Clean the end of housing thoroughly so that dirt will not enter housing with the installation of the new seal.
  7. Lubricate the seal thoroughly with lubriplate and install seal with Installer J -6219. CAUTION: When driving seal into housingwithToolj-6219, it is important to place steel back-up washer between installer and seal so that driving force may be transmitted through washer to seal, preventing possibility of seal caving in due to round shoulder on O.D. of tool. Also, care should be taken to see that snap ring is fully seated in housing groove after dust seal and back-up washers have been installed.
  8. Start engine and turn wheel to right and check for leaks.
  9. Remove tape and reinstall pitman arm and starter splash pan.
  10. Kit No. 2 – Gr. 6.825 Part #5685028 End Cover, Adapter and Valve Mounting Seal Service Kit.

The end cover leaks usually occur between the adapter and housing. To help remedy this condition, a change is being made in the „O“ ring seal; at this location, the new „O“ ring will have a larger cross-sectional diameter (this new „O“ ring is identical to the „O“ ring used between the end cover and the adapter.) Since this is an after- job change , both the new and the old style „O“ ring seal will be supplied in the service kit. In order to accommodate this new ” 0” ring, the groove width in the adapter has been increased by .038′ ‘. See Fig. 65.

1956 Buick Steering Gear Feeler Gauge

1956 Buick Steering Gear Feeler Gauge

If there is any doubt as to an adapter being a new or old type, a quick check may be made with .115″ feeler gauge. The .115″ feeler gauge will fit in the after job adapter; however, it will not fit in the first jobs. See Fig. 65. NOTE: Both type adapters are interchangeable with each other provided the correct seal is used. If leaks should occur in the area of the end cover they may be eliminated by using this kit and following the instructions for installing it as outlined below:

  1. Remove steering gear from car.
  2. Remove the control valve retaining bolts and lift control valve and linkage cover, with actuator lever, off the gear housing.
  3. Remove coupling flange as outlined in 1956 Shop Manual (par. 6-18, sub. par. 2).
  4. Remove four end cover retaining bolts.
  5. Turn worm shaft to the left until the piston bottoms in the housing. A slight additional turn to the left will loosen the end cover.
  6. Remove end cover.
  7. if the adapter remains in the housing when removing end cover, slide adapter out of housing enough to facilitate „O“ ring seal replacement; this may be done by carefully pulling on worm shaft. CAUTION: If piston is pulled out of housing too far, oil ring will leave cylinder wall and hang up on adapter seat.
  8. Lubricate new ”O” ring with lubriplate and install on adapter, then install new end cover seal.
  9. Reinstall end cover using new end cover to adapter „O“ ring seal. NOTE: „O“ rings have a tendency to swell when subjected to oil for a period of time; therefore, it is recommended that a new „O“ ring seal always be installed.
  10. Install the valve and linkage cover, using new „O“ rings at the linkage cover and valve to housing.
  11. Install gear in car and check for leaks.

Kit No. 3 – Gr. 6.524 Part #5685029 Worm, Side Cover and Valve Seal Service Kit.

This kit is to be used when the valve assembly is dismantled or a complete gear overhaul is made. It may be pointed out that this kit cannot be used alone when servicing a gear. One or more corresponding kits must be used as required to replace the seals that are removed when dismantling the valve or complete gear. NOTE: Before removing gear from car, remove pitman shaft seal as d escribed in Part A above. Procedure for overhauling gear assembly is thoroughly covered in 1956 Shop Manual.

Kit #4 – Gr. 6.822 Part #5684554 Nut, Lash Adjuster Seal

This nut is a service item and also went into production as an after-job change. All power steering gears having numbers 58-6 or higher will have this pitman shaft lash adjusting lock seal nut. The nut should be used as a service fix when a leak is detected around the adjusting screw. It is not necessary to replace the adjusting screw and cover as previously recommended unless they are damaged.

Kit No. 5 – Gr. 6.806 Part #5684069 Housing End Plug Service Kit

This kit should never be used unless it has definitely been established that the end plug seal is leaking. If it is necessary to remove the end plug to replace the seal, extreme care must be exercised to prevent the plug from scoring the sealing surface of the housing. It is recommended that the crimped end of the plug be completely ground off before attempting to drive the plug out of the housing.

The suggested flat rate times for installing the parts for each of the above kits are:

Kit #1 – Pitman Shaft Seal and Wiper Seal Service Kit .7 hr.

Kit #2 – End Cover Adapter Valve Mounting Seal Service Kit (includes removing gear) 2 .7 hr.

Kit #3 – Worm, Side Cover and Valve Seal Service Kit (Overhaul time) 4 .1 hr. (If the valve is all that is disassembled, the time will be .4 hr.)

Kit #4 – Nut Lash Adjusting Seal .6 hr. (includes D & C pitman arm adjusting gear lash)

Kit #5 – Housing End Plug Service Kit (includes removing gear) 3.1 hr.



We are still receiving reports questioning the type of power steering oil being used in production because it has the appearance of engine oil.

Due to a change in supply, the power steering oil used in some assembly plants has a bluish cast similar to some types of motor oils, but it is definitely not motor oil; therefore, do not change this oil. If additional oil is required in the power steering reservoir, the following oils are approved: Special Buick Oil for Dynaflow, available through Buick Parts Warehouses under Gr. 4.101 or Automatic Transmission Fluid, Type A, that has an AQ-ATF number embossed in the lid of the can for identification.



Following is a reprint of Special Red Band Service Letter, Dealer No. 167. This letter supplements the power steering gear leakage information covered in BPS 2.398 dated December 8, 1955.

In Step Two (2) it was stated that a leak past the pitman shaft lock adjusting screw could be caused by a loose lock nut (not properly torqued) or poor threads in the adjusting screw hole. However, we have received product reports stating that in some cases leaks still exist between threads in the lock nut and the adjusting screw, even when the nut is torqued to 25-30 ft. lbs. and the threads are not damaged.

To correct conditions of this type a new power steering gear pitman shaft lash adjusting lock seal nut Gr. 6.822 Part #5684554 has been released for service and is available through all parts warehouses. This new nut has a nylon seal embedded at the top (crimped end of nut). The nylon seal I.D. is smaller than the thread I.D. of the nut; therefore, when nut is installed on the adjusting screw, new threads are cut into the nylon which insures effective sealing at this critical point. Whenever installing a new seal nut it will be necessary to disconnect the pitman arm from the intermediate tie rod and perform pitman shaft adjustment as described on page 68, paragraph 8-13 of the 1956 Product School Manual.

Note: Never attempt to adjust steering gear with pitman arm connected to the intermediate rod.

When installing this new nut the nylon end must be up; however, if the adjusting screw passes through the cover at an angle, preventing the nut from becoming fully seated on the cover, it will also be necessary to replace both the cover and screw.




We have been advised by our Parts Department that they will no longer service the Power Steering Master Seal Service Kit Gr. 6.507 Part #5685027. However, they will continue to service the individual kits as follows:

Gr. 6.855 Part 5683796- Pitman shaft seal and wiper service kit
Gr. 6 .825 Part 5685028 – End cover adapter and valve mounting seal service kit
Gr. 6.524 Part 5685029 – Worm, side cover and valve seal service kit
Gr. 6.822 Part 5684554 – Nut, lash adjuster seal. Gr. 6.806 Part 5684069 – Housing end plug service



Power Steering

To date, there has been an increasing number of complaints regarding wander with cars equipped with power steering. Through investigation it has been found that many of these cases may be attributed to loose gear adjustments. The loose adjustment may be ball nut preload, thrust bearing preload or overcenter load, or a combination of these adjustments. However, in the majority of cases, it is a loose overcenter adjustment that causes the car wander. Whenever this type of complaint is encountered it is advisable to check the lash of the steering gear with particular attention to the overcenter adjustment.




Saginaw Steering Gear has informed us of a change in the pitman shaft dust seal for the 1956 hydraulic steering gear. A 45° chamfer has been added to the I.D. and the entire seal has been impregnated with a wax substance. See Figure 66.

1956 Buick Pitman Shaft Dust Seal

1956 Buick Pitman Shaft Dust Seal

The new style seal is now being used in production. When installing the seal the chamfered side of the seal should be facing inward and the sharp edge of I.D. toward outside of housing. The installation procedure, however, is the same as for the 1st type seal.

Should replacement of the new style seal be encountered in the field, it should be replaced with regular parts stock.



To meet production demands, approximately 400 power steering gear assemblies have been built with a different type side gear cover. While these covers differ in appearance, they are interchangeable with those from regular service stock.

All power steering gears equipped with the new cover can be identified by a daub of green paint on the side cover and also by the flat, smooth appearance of the cover (no strengthening ribs). If any difficulty is encountered with power steering gear covers of this type, they may be replaced with those from regular service stock. However, we would like a product report submitted (in the regular manner) giving all pertinent information as to type of failure, car serial number, model, mileage, etc.



The 1956 power steering gear requires the use of a slightly modified pitman arm puller. However, the present puller, J-5504, used on 1955 and earlier model cars can be reworked as follows:

  1. Clean the surface of the puller adjacent to the opening.
  2. Scribe a mark 1/16″ in from edge all the way around the opening, See Figure 67.
1956 Buick Pitman Arm Puller

1956 Buick Pitman Arm Puller

  • Remove the 1/16″ of metal by grinding or filing.
  • Remove all burrs and rough edges.
  • The puller can now be used for all current model cars through 1956. Pitman arm puller J -5504, can also be purchased from the Kent-Moore Organization with the above modification already incorporated in it.



    Engineering advises that 5,000 Flint built cars will have the following changes made in the power steering unit for field test.

    1. Teflon piston rings
    2. Double lip pitman shaft seal
    3. Redesigned ball nut with die cast ball return guide caps eliminated as shown in Figure 68.
    1956 Buick Power Steering Changes

    1956 Buick Power Steering Changes

    The gears may also be identified by a daub of yellow paint on the side cover. If trouble should be encountered with any of the above mentioned parts, they should be replaced with the standard 1956 parts listed in the parts catalogue, and the defective parts returned to the Zone M.R. Room with all pertinent information. Also, note on the AFA and the material return tag that parts are field tested parts in order that they may be quickly identified.



    There have been reports received whereby some power steering cars receive more power assist in one direction than they do in the other. These complaints can usually be traced to one of two sources.

    • Internal leaks at one or both of the white teflon seals. If this condition exists it can be identified by the fact that there will be normal assist on right turns but less than normal assist on left turns only. The reason for this characteristic is that when power is required to make a left turn, high pressure oil is supplied to the upper side of the piston. If oil leaks past either of the teflon seals it is dumped directly into the low pressure area. This causes a loss of pressure on the upper 2nd of the piston which, naturally, gives less assist in that direction.

    If this condition exists it is advisable to replace both teflon seals.

    • The second possible source of trouble is the location of the valve body. The positioning of the valve body is very important since the valve body controls the steering effort in either direction. If the valve centering spring should be compressed, even a very slight amount, it will affect the amount of assist in one direction or the other, depending on which way the spring is compressed.

    If this condition should exist the correct method of aligning this valve is to loosen the three attaching bolts, allowing the valve assembly to float or seek its own location. Tighten the end bolt finger tight. Then the two side bolts. Repeat bolt tightening sequence, applying a final torque of 15 to 20 ft. lbs.



    1956 Power Steering Gear

    Reports have been received that the vent washer, which is underneath the reservoir cover bolt, on some power steering pumps, were installed upside down. In order to clarify any misunderstanding in the proper method of installation of this washer, it must be understood that there are two (2) types of these washers in use (aluminum and steel). When installing these washers, the aluminum washer must have the vent groove down. This eliminates the possibility of the reservoir cover bolt head from cutting into the washer and plugging the vent. However, with the steel washer, the vent groove is up. The primary reason for having the groove up is to help eliminate oil leaks at this area. The bolt head will not cut into the steel washer as it does with the aluminum; therefore, it is not as susceptible to plugging.

    Saginaw Steering Gear is using up its stock of aluminum washers and will eventually use steel washers 100%.



    We have been advised by Saginaw Steering Gear Division that a change has been made in the pump cover and valve body of the Power Steering Gear.

    In order to reduce the amount of oil drag in the restricted passage which occurs when the oil is cold, the length and diameter of the discharge orifice in the pump cover was changed to (.02” long x .1285 diameter instead of .18″ long x .116 diameter previously used.) See inserts Figure 68. This change should help overcome increased turning effort under cold oil conditions.

    In addition to this change the ball check and related passageways in the control valve assembly have been eliminated. See View A & B, Figure 69.

    1956 Buick Power Steering Pump

    1956 Buick Power Steering Pump

    1956 Buick Power Steering Pump Check Ball

    1956 Buick Power Steering Pump Check Ball

    The purpose of this ball check was to allow the oil in the gear assembly to be circulated through the gear, in case of a pump failure, without having to pass through the pump. It was felt that if the oil were forced through the pump on manual steering that the steering effort would be greatly increased, and the oil would be forced out the vent hole in the reservoir cover. However, upon investigation, it was found that the above conditions did not exist, and the elimination of the ball check, therefore, has no adverse effects on steering without power assist. Also, it may be stated that the elimination of the ball check will also eliminate the service complaints concerning this check ball getting into the pressure passageways of the valve. This change went into effect on approximately January 2, 1956.