1952 SERIES 50-70

Supplements Section 7-B, 1952 Shop Manual

The following supplementary power steering information is intended to familiarize mechanic personnel with developments recently introduced:


Oil Reservoir

The Series 50 power steering unit is similar, from a design and maintenance standpoint, with the Series 70 gear. The only notable exception is use of an oil reservoir integral with the pump assembly. This feature eliminates the need for bleeding the system and aids in maintaining consistently quiet operation.

Oil Level

At the start of production a few reservoirs got into the field without proper oil level markings. The correct level, whether marked or not, is 1″ from the top of the can rim (with cover removed). Reservoirs that are marked have either a rectangular indentation or scribed line, 1″ from the top of the can, together with the marking “Oil Level”.

Oil Filter

Due to characteristics of the rotor type oil pump supplied by Eaton, the manufacturer has included an oil filter in the reservoir. Original equipment is a Purolator No. P-176 filter element. The element does not require replacement for the life of the automobile unless obviously damaged or rendered useless in some other manner.

Gears equipped with a Vickers vane type pump do not include an oil filter.

Pressure Relief Valve

All Series 50 Eaton pumps incorporate a dual function pressure relief and flow control valve in the pump cover. This design eliminates the possibility of excessive pump pressure at high engine speeds.


Pressure Relief Valve

In order to avoid excessive pump pressure at high speeds, Series 70 Eaton pumps manufactured since August 29, 1952 have incorporated the dual-function pressure relief and flow control valve same as used in Series 50 pumps. The first job to include the new valve has the code number “H-29-F” stamped on the machined boss on the pump cover. This designates that the pump was manufactured August 29, 1952 and, of course, all succeeding pumps will also include the new valve.

1952 SERIES 50-70

As you probably know, numerous improvements have been made in Power Steering gear components since the first units were introduced. In order to determine the effectiveness of these changes it is necessary for us to have the steering gear code number whenever Product Reports, A.F.A.’s and other reports concerning field difficulties are submitted.

The code number is hand stamped on the power rack guide cover, as shown in Figure 32, and appears as a 1, 2, or 3 digit number.

1952 Buick Power Steering Code

1952 Buick Power Steering Code

For example, the code number “19r indicates that the gear was produced on the 197th day of the year – or July 15th. The code may not always appear in the same location and may be upside down as the guide cover can be installed in either position. An additional casting number appears across the center of cast guide covers, but not on covers having pressed metal construction. Do not confuse this with the code number.

When the steering gear is installed, the guide cover is obscured by the left hand fresh air intake tube and it may be necessary to use a mirror and light in order to obtain the code. We ask, however, that servicemen make every effort to provide this number on Product Reports, A.F.A.’s and other reports dealing with Power Steering difficulties.



1952 SERIES 70

We receive occasional complaints of noise in the Series 70 power steering assembly, that cannot be eliminated by subsequent service or bleeding operations. Some noise is inherent under certain operating conditions, and it is well to recognize its occurrence so that needless work can be avoided and a satisfactory explanation can be made to the owner.

When the steering wheel is turned fully right or left (when parking or making “U” turn) a “whine” or slight “hiss”, or both, may be heard. The sound level is usually increased when the engine is accelerated. The “hiss” is caused by oil moving through the control valve when pressure is relieved or built-up. The whine is caused by the pump, at the extreme ends of wheel travel, where maximum pressure is exerted. This noise is similar to that heard when windows are raised on cars equipped with hydraulic controls.

Both of the above conditions are normal and are barely audible when the car is being driven in a normal manner.

Noisy operation under normal conditions usually indicates presence of air in the hydraulic system. Air noise normally occurs after some unit in the pump or gear is serviced or replaced, or when an oil line has been disconnected for any reason. The system must be bled in order to obtain a satisfactory correction.


Before bleeding the unit, make sure that the hydraulic valve, power cylinder and pressure and return line hoses are filled as completely as possible with Dynaflow oil. All oil line connections should be tightened and the oil reservoir filled to specified level. This helps eliminate part of the excessive air and shortens the time required to satisfactorily bleed the system.

The Eaton pump is self-bleeding and it is only necessary to run the engine at approximately 1500 RPM for two or three minutes and then rotate the wheels through several cycles until the noise level diminishes.

If the car is equipped with a Vickers pump, the following operation is necessary:

  1. Remove the pipe plug from the top of the pump manifold until oil comes out of the opening. Reinstall and tighten plug.
  2. Start engine and run for two or three minutes at’ approximately 1500 RPM.
  3. Remove manifold plug and check oil coming from opening. If no air apparent in the oil mixture, reinstall the plug. If air is present, run the engine on idle until clear oil comes from opening and reinstall plug.
  4. With engine idling, rotate the wheel through several complete cycles. If no noise is apparent, the system is bled. If noise persists, stop engine, let stand for 10 minutes and repeat the bleeding operation until no noise is apparent at idle speed. Some air noise may still occur when the engine is “revved-up”, but quiet idle operation will insure a satisfactory noise level under normal operating conditions.

NOTE: Throughout the bleeding operation, some means should be employed to prevent oil issuing from the pump from spilling or dripping on chassis parts.

  1. Check oil level in reservoir and fill to specified level.

Alternate Bleeding Procedure For Vickers Pump

  1. Remove pipe plug from top of pump manifold and install a bleeding tube from the manifold opening into the oil reservoir.

NOTE: A suitable tube can be made up by using a 1/4″ “Weatherhead” fitting and a 3” length of 1/4” copper tubing, fitted on one end with a fitting which will mate with the female end of the “Weatherhead” fitting. The balance of the tube consists of a 20″ length of transparent plastic tubing with a 1/4″ inside diameter. The plastic tubing fits over the open end of the copper tube and should be overlapped as required so that the entire assembly is approximately 22 3/4″ long. The tube is installed with the fitting end at the pump manifold opening and the other end through the oil reservoir filler opening or a suitable container.

  1. Start engine and run at 1500 RPM, using- a strong light to observe the oil flow (from pump to reservoir) through the transparent section of the bleeding tube.
  2. When oil is free of air pockets or bubbles, idle engine, remove bleeding tube and reinstall pipe plug in manifold.
  3. With engine idling, rotate the wheel through several complete cycles. If no noise is apparent, the system is bled. If noise persists, stop engine, let stand for 10 minutes and repeat the bleeding operation until no noise is apparent at idle speed. Some air noise may still occur when the engine is “revved-up”, but quiet idle operation will insure a satisfactory noise level under normal operating conditions.

NOTE: Throughout the bleeding operation, some means should be employed to prevent oil issuing from the pump from spilling or dripping on chassis parts.

  1. Check oil level in reservoir and fill to specified level.


This material covers only those causes of trouble which may be due to the hydraulic power mechanism. Causes which are due to the mechanical components of the steering gear, linkage, and front suspension are the same as described for the standard steering gear in Paragraph 7-3 of the Buick Shop Manual.

Before assuming that the hydraulic power mechanism is at fault, make certain that the mechanical components are in proper condition. The mechanical items include: Front wheel alignment, tire condition and pressure, wheel bearing adjustment, lubrication and adjustment of steering linkage, and proper alignment of steering gear in mountings to eliminate binding.

  1. Excessive Play or Looseness in Steering Mechanism.
    • Excessive lash between pitman shaft sectors and the ball nut or power rack.
    • Loose worm thrust bearing adjustment. (3) Valve spool sticking in valve housing.
  2. Front Wheel Shimmy
    • Air in hydraulic system, requiring bleeding. (2) Excessive lash between pitman shaft sectors and the ball nut or power rack.
  3. Poor Centering or Recovery from Turns
    • Binding of steering shaft.
    • Valve spool sticking in valve housing.
    • Faulty valve centering springs.
  4. Rattle or Chuckle in Steering Gear
    • Excessive lash between pitman shaft sectors and ball nut or power rack.

Note: A very slight rattle may occur on turns because of the increased lash off the “high point“. This is normal, and lash must not be reduced below specified limits to eliminate this slight rattle.

Hard Steering When Parking

Note: It is a normal condition to feel an increase in parking effort if the hydraulic oil temperature exceeds 170 degrees F. The oil temperature may exceed 170 degrees F. after excessive turning or on very hot days.

To determine whether hard steering actually exists, place car on clean dry floor, apply brakes, and with engine idling turn steering wheel from side to side to bring oil temperature to approximately 170 degrees F. Apply Gauge J5178 (15 lbs.) to a spoke at rim of steering wheel and check the pull required to turn the wheel steadily, with gauge held at 90 degrees to the spoke. If the pull required to turn the steering wheel exceeds 10 pounds, check the following possible causes:

  • Pump drive belt loose. Adjust to proper tension. (2) Low oil level in reservoir. Fill to proper level. Note: If oil level is excessively low, check all hydraulic system lines and joints for evidence of external leakage of oil.
  • Air in hydraulic system. Tighten valve cover bolts and all oil line connections on steering gear, pump and reservoir, then bleed the hydraulic system. (4) Insufficient oil pressure. If the preceding suggestions do not reveal the cause of hard steering, make the following tests of oil pressure:
  1. Testing Hydraulic Oil Pressure
    • Disconnect the pressure line hose at oil pump, attach Gauge J 5176 to pump and connect the hose to end of gauge where the valve is located.
    • With engine idling at 450 RPM and gauge valve open, note the oil pressure on the gauge while turning steering wheel from one extreme position to the other. Especially note the maximum pressure which can be built up with the wheel held in either right or left extreme position. Caution: Do not hold wheel in extreme position for an extended period because it will drastically increase the oil temperature and will cause undue wear on the oil pump relief valve.
    • With oil temperature between 150 degrees F. and 170 degrees F, the maximum oil pressure should not be less than .700 p.s.i. for satisfactory power steering operation.
    • If the maximum oil pressure is less than 700 p.s.i., it indicates trouble in the pump, or external oil lines, or steering gear, or a combination of these parts. To eliminate the lines and gear, close the gauge valve and quickly test pressure of the pump only, with engine idling at 450 RPM, then open the valve to avoid increasing oil temperature.
    • Comparing the maximum pressures obtained in these two tests will indicate the source of trouble as follows:
      • First test (step 2) pressure low, and second test (step 4) pressure normal – indicates faulty external oil lines or steering gear.
      • First test (step 2) and second test (step 4) pressures equally low – indicates faulty oil pump.
      • First test (step 2) pressure low, and second (step 4) pressure higher but below normal- indicates faulty pump and also faulty external oil lines or steering gear.
  1. Low Oil Pressure Due to Pump
    • Pump drive belt loose. Adjust to proper tension.
    • Low oil level in reservoir. Fill to proper level.
    • Oil too light. Change to specified Dynaflow oil.
    • Loose pump assembly bolts. Tighten all pump bolts.
    • Faulty internal pump condition such as – dirt or sludge, sticking or scored relief or flow control valve, worn rotor parts, shaft oil seal leakages. Remove pump and disassemble for inspection.
  2. Low Oil Pressure Due to External Oil Lines
    • Loose connections. Clean and tighten all connections and test for oil leakage.
    • Leakage at hose unions or oil tube elbows. Remove leaking unions or elbows and install new “O” ring seals.
  3. Low Oil Pressure Due to Steering Gear
    • Leakage at worm shaft seal or cylinder piston rod seal, evidenced by an accumulation of hydraulic oil in gear housing. Leakage at valve cover seal, evidenced by oil dripping from top of valve cover. Remove gear assembly for replacement of seals.
    • Pressure loss in hydraulic valve or power cylinder. Remove gear assembly for disassembly and inspection.
  4. Oil Pump Noisy
    • Air in hydraulic system. Tighten all external line connections and bleed hydraulic system.
    • Reservoir air vent plugged. Remove filler plug and clean vent.
    • Drive belt too tight. Adjust to proper tension. (4) Oil too heavy. Change to specified Dynaflow oil.
    • Sludge and dirt in pump. Remove pump and clean out.
    • Bearings, shaft or other rotating parts worn. Remove pump and disassemble for inspection.




There have been cases where the spool valve plungers have taken five distinct nicks or chips from the seal as shown in View A, Figure 33 (“O” ring-part No. 5661386) at either the upper or lower end of the valve assembly.

1952 Buick Power Steering O-Ring Sealing

1952 Buick Power Steering O-Ring Sealing

When this occurs, it is an indication that the seal retaining groove in the steering worm and sector housing or in the steering tube power valve cover may be too small in diameter. Another possibility is that the “0” ring or seal flattens out too much allowing the valve centralizing spring plungers to chip the soft neoprene seals.

It must be cautioned that this condition may be serious as the rubber chips could cause erratic steering.

In other cases, only two or three nicks or chips are noted as in View B of Figure 33. This usually indicates that the spool valve assembly was not centered properly when the unit was assembled. The field requires that spool valve aligning tool No. J -5283-A be used in order to do this work properly

Summary of recommended procedure:

  1. Carefully examine both power steering valve seals if a gear is disassembled for any reason.
  2. If the lower seal (Gr. 6.556, No. 5661386) has five chips or gouges on the inside diameter replace the steering worm and sector housing (Gr. 6.803, No. 5663953).
  3. If the upper seal (Gr. 6.556, No. 5661386) has five chips or gouges on the inside diameter replace the valve cover (Gr. 6.554, No. 5663957).
  4. Replace both seals (5661386) every time the valve assembly is removed and make certain the Valve Aligning Tool No. J-5283-A is used properly.
  5. Late type shaft seals (5663834 and 5663837) should also be used to prevent oil leakage each time a valve assembly is removed.

Valve Aligning Tool No. J-5283-A has been included with the Group B tools that are sent out to the field. This tool is not with the Group A tools, however, this tool may be ordered individually from the Kent-Moore Organization if desired.




There is a new lower worm shaft seal being used in production on all series power steering units. This new seal (Figure 34) is used to reduce the tendency of gear oil from leaking into the hydraulic circuit and conversely from the hydraulic oil leaking into the gear box unit.

1952 Buick Power Steering Seals

1952 Buick Power Steering Seals

In some instances where this condition of oil transfer has occurred, the field has reported that the old seal was on the worm shaft backwards.

When a power steering unit is overhauled, it is suggested that an inspection of the lower worm shaft seal be made. If this seal is not of the new type, it should he replaced. This new seal may be identified by various markings as shown in Figure 34.

On the back face of the new seal there will be the letters E P which are the vendor code. 90 degrees counter clockwise from the letters E P will be production mold Number 2. The Number 2 is identification of the new stock.

This seal is used in Kit 1391012 Group 6.507. All inventory on hand at both Factory No. 18 and the field warehouses is to be reworked when the new seal is received. The Seal Kit will be identified as having been reworked by a date stamp.

All inventory of Part 5663834 and Part 1391012 of the old design is being returned to Factory No. 18 by the field warehouses as their new stocks are received.

Since November 6, 1952, all power steering units produced (gear code 311) have the new type seal.





This adjustment is to be made after Ball Nut and Steering Shaft Assembly, End Cover, Thrust Bearings, Valve Assembly, Locknut and Valve Cover Adapter are assembled to Steering Gear Housing. Proceed as follows:

Turn hand wheel to extreme left tum, compressing valve springs and tighten locknut firmly to remove all end-play of Valve Spool. Back-off nut and retighten lightly. Release hand wheel, make sure nut and thrust bearings exerts light pressure against spring loaded plungers and stake nut in place. Turn the wheel through the full range, about five and a half turns, to check for free action.



This adjustment is made after all the above parts are assembled and adjusted. Assemble Power Rack and Cylinder Assembly, Pitman Shaft Gear, Side Cover, Power Rack Guide Cover, and estimated number of Power Rack Guide Cover Shims. Leave Power Rack Guide Cover Bolts loose. With Gear on center, adjust Pitman Shaft Thrust Screw so that pull on 9″ radius is 1 to 1 1/2 lbs. Tighten Locknut.


With gear on center, note pull on 9″ radius after over center adjustment is made. Select shims to give a pre-load in addition to the over center load of 1/8 to 1/4 lb. pull on a 9″ radius.



The drag due to seals must not exceed 1/4 lb. pull on a 9″ radius to rotate the Steering Shaft.


Pull on 9″ radius with gear over center must be 1 1/8 to 2 lb.




There have been a few cases where other than the recommended Dynaflow oil has been added .to the power steering tank in error. When this occurs it is necessary that the entire hydraulic steering circuit be flushed as follows:

  1. Raise the front wheels off the ground.
  2. Disconnect the return hose at the rear of the pump.
  3. Install a sealing cap at the return outlet on the pump, so oil will not escape when the circuit is being flushed. The cap may be ordered free of charge from the Service Department, Buick Motor Division, Flint, Michigan.
  4. Wipe off all traces of dirt and remove the pump reservoir cover on Series 40 and 50. Remove filler cap on top of reservoir of Series 70 units.
  5. Direct the return hose, which is fastened to the gear into an empty can. At this point, sufficient automatic transmission oil type “A”, (AQ-ATF- …), (1 1/2 to 2 gallons) should be obtained for flushing out the circuit.
  6. Start engine and let it idle only.
  7. Continually add new oil to reservoir to maintain level, at the same time turning steering wheel as fast as possible, using full travel from right to left. Do not hit stops.

NOTE: Be careful never to run pump out of oil. Shut off engine if running short.

  1. When the new oil is used up, shut off engine, remove the cap from the pump, and connect return hose.
  2. Check for proper oil level and install reservoir cover on Series 40 or 50 and filler cap as required by Series 70 units.




It has been found necessary to make a campaign change on all Power Steering equipped Series 70 cars. This change consists of installing a new pump to gear pressure hose. The new hose is 23″ long; 2 inches longer than the original type hose used, which was 21″ long. In addition, it will take considerably more pressure.

The new hoses, as they are marked from the Parts Department, will have a daub of yellow paint for identification. They will be ordered and shipped under Group No. 6.670, Part No. 5664994.

Old hoses should be returned to the Zone MR Room. It will be possible to list more than one car on an AFA, providing Serial Number of each car campaigned is given. Flat rate time allowance for removing the air cleaner, changing the hose and bleeding the system and installing the fluid will be one hour (1 hr.) per car.

The 23″ hose was started in production approximately August 1, 1952. Any car with a 23″ hose does not have to be changed.

On all’ power steering units, new or old, special attention should be paid the hoses and hose connections. It’s suggested that during the inspection given while greasing a Buick, equipped with power steering, that the service man be alerted to watch for any erratic hose conditions which might cause trouble.

Special attention should be given to the power steering hose connections. Figure 35 is an example of an overstressed 21” power steering hose.

1952 Buick Power Steering Hoses

1952 Buick Power Steering Hoses

This hose has caused a power steering failure and is a good example of what condition to watch for. Under no conditions should a power steering unit be operated or released for service, if this, or similar hose conditions, are present.



1952 SERIES 70

The power steering pump drive belt tension should be checked and adjusted if necessary during the 2000 mile inspection. This belt has correct tension when one side can be depressed 3/8″ with thumb pressure applied midway between the pulleys. To adjust belt, loosen the pump mounting bolts and move the pump horizontally as permitted by the slotted bolt holes in the mounting bracket. After correct adjustment is obtained, tighten mounting bolts securely.



ALL SERIES 40-50, 1952 ALL SERIES, 1953

Since October 20, 1952 all Series 40 and 50 production models are now produced with the new zero caster knuckles, and subsequent zero caster setting.

It is felt that the king pin inclination will give the riding qualities that were attributed to the caster angle. The return of the wheels to center is still achieved due to the load rise and fall in the turning radius.

As is indicated in Figure 36 the service specification on the zero caster are 3/4 degree positive to 1/2 degree negative.

1952 Buick Front Wheel Alignment

1952 Buick Front Wheel Alignment

In going to the use of zero caster, it is felt that it will reduce the tendency of front wheel shimmying. It is also felt that the zero caster will subsequently effect uneven tire wear which is attributably to this shimmying condition.

Starting with the 1953 production, all series and models will have completely interchangeable suspension parts except for, of course, springs.

It must be cautioned however that zero caster on the earlier 1952 model cannot be readily achieved, as these models, prior to the production change, have not the adjustment range required. To try to achieve zero caster with an early model might cause excessive drag. It is advisable, however, to set caster on these early models as low as possible in an effort to acquire the benefit of zero caster where necessary.