We have received reports of speedometer drums sticking or hanging up at a particular speed and when the speedometer is removed and sent to U.M.S. for repairs nothing can be found wrong with it.
This type of failure has been traced to distortion of the speedometer housing during assembly causing interference between the drum and the black retainer plate behind the speedometer numerals. When the speedometer is removed to be repaired, the housing returns to its normal shape and the interference no longer exists. If this condition is encountered it can be corrected by first loosening (do not remove) the four ( 4) mounting screws shown in Figure 56, then lightly pry forward the drive end of the speedometer. See Figure 56.
While holding this end of the speedometer forward first tighten the two (2) forward screws and then the other two (2) screws.
This operation may be performed with the speedometer housing in the car and will eliminate unnecessary speedometer removals.
TIRE BALANCING PROBLEM
Since the inception of the tubeless tires, tire balancing has been a problem in the field. In a number of cases it has been reported that the balancer dough which is applied to the crown area of the tire came loose, making it impossible to get a good balanced tire. The cause of the balancer dough coming loose was due to the method in which the tire liner was prepared for adhesion of the counter balance dough material.
The tire manufacturers have advised that they have improved their cleaning operation of the tire inner liner before the balancer dough is applied and also have adopted a new balancer dough compound which gives better adhesion to the tire liner.
This new balancer dough will be applied to all tires 100% by July 15, 1956; therefore, if any difficulty is encountered with tire balancing on cars built after July 15, 1956, submit a complete report to your Zone Service Manager giving all pertinent information such as car serial number, model, mileage , make and serial number of tire.
RADIATOR SIDE BAFFLE CHANGE
1956 Air Conditioned Cars
A change is being made on all 1956 after job air condition equipped cars whereby the opening in the radiator side baffle, through which the compressor discharge line passes, has been widened to allow more clearance for this line.
On all first type dealer installed air conditioner kits, it will be necessary for the service man to cut out that portion of the side baffle, shown in Figure 57, to allow clearance for the compressor discharge line, before unit is installed.
INSTRUMENT CLUSTER CHANGE
For your information a change is being made in the instrument cluster assembly, in that the signal green and fire orange colors have been removed from gas gage and ammeter back dials and replaced by black to match retainers.
NEW SHOCK ABSORBER BOLT
We have received a few reports that the rear shock absorber mounting bolts on 1956 models work loose because of improper assembly. Engineering has released a new 7/16 – 20 x 2 1/4 (300M Steel) bolt, Gr. 8.900 Part #454961 and special alloy nut Gr. 5.002 Part #456939 that will withstand the necessary 80-90 ft. lbs. of torque . This new bolt can be identified by the 6 marks on the head of the bolt which indicate that it is made of 300M Steel. See Figure 58.
Use only the 300M Steel bolt and special nut when correcting loose shock absorber complaints. No other combination will hold the necessary torque without stripping.
CASTER SPEC. CHANGE
We have been advised by our Engineering Department that the caster specification given in Fig. 7-16 of the 1956 Shop Manual has been changed. It was 1/2° positive to 1 1/2′ negative. It now is 0° to 2° negative with 1° negative desired at both wheels. This specification was changed because increased negative caster angle indicated better car handling. It has been further requested by the Engineering Department, that item number 9 on the 1956 2,000 Mile Inspection and Adjustment Sheet be changed to read as follows:
- Check and correct toe-in if necessary.
Also, Item No. 27 on the 1956 New Car Inspection and Adjustment Sheet should read as follows:
- Check steering wheel 3rd spoke for correct position and correct if necessary. Check front wheel toe-in and correct if necessary.
You will note that checking of caster and camber has been eliminated; however, we are not recommending that the check be ignored completely. If an owner is having trouble with car wander, steering or handling, these items should be checked and corrected as required. We would also like to bring to your attention that the factory does not favor bending steering arms, knuckles or supports either hot or cold. Therefore, we strongly discourage this practice.
NOTE: Neither inspection sheet mentioned above will be revised to show this change because our yearly supply of these forms has already been printed.
INACCURATE GAS GAUGE
Gasoline Gauge Dash Units are calibrated at the factory to be accurate with the generator charging at 14.2 volts. Gauges should not be replaced as inaccurate unless the reading is taken with the engine running at fast idle. The reading can be as much as an eighth of a tank off if taken with the engine not running or at slow idle with generator not charging.
A contributing factor to low reading is the location of the gauge pointer in back of the graduations on the plastic face. From the drivers location this parallax condition results in a low reading by visually moving the dots to the right of the pointer. In checking the gauge, take the reading from directly in front of the gauge.
Don’t attempt to bend the tang in the tank unit to remedy a low reading dash unit. The result may then be a quarter tank reading with an empty tank. If trouble actually exists, make certain it is the tank unit, the dash unit, the wiring or a faulty terminal connection. Then replace only the affected part, never both dash and tank unit. Follow test procedure section 10-57 of your Shop Manual.
WHEEL SEAL CEMENT
A procedure for repairing holes in wheel rims was given on Page 151 of BPS Bulletin No. 2.389, dated May 20, 1955. The procedure outlines involved the use of a product called “Seal All” marketed by the Allen Products Corp., Detroit, Michigan. The correct name is “Seal All Wheel Seal” and it is sold through hardwares, or automotive supply houses. In the event that this product cannot be located locally, please address an inquiry to Allen Products Corp., 20450 Sherwood Avenue, Detroit 34, Michigan. Allen Products will then furnish the name and address of the nearest source.
REBORING BRAKE DRUMS
It has been brought to our attention that some dealers have been exceeding the factory recommended limits when reboring brake drums to put them back into service.
If a brake drum is to be rebored, enough metal should be removed to obtain a true, smooth braking surface. If a drum does not clean up when rebored to a diameter of 12.083″, it must be replaced. Removal of more metal will affect dissipation of heat and may cause distortion of the drum.
NOTE: Paragraph 9-12, sub. par. c “Reboring Brake Drum”, of the 1956 Shop Manual states that drum should not be bored larger than 12.063. Please change this figure to 12 .083.
FAN SHROUD RATTLE
To eliminate any complaints of rattle between the fan shroud and lower radiator tank, a change is being made in production to install a rubber bumper in the bottom of the shroud. Engineering advises that the use of rubber bumper Gr. 1.216 Part #503865 can be easily installed by drilling a 9/32″ hole in the bottom section of the shroud, approximately 5/16″ in from the edge of the shroud.
REAR SHOCK AND SPRING CHANGE
To improve the riding quality of certain 1956 models and reduce complaints of cars bottoming, heavier springs and shock absorbers will soon be used in production in the following manner:
All 40 and 60 series cars except estate wagons will have stiffer front shock absorbers available under Gr. 7.345 Part # 553122 6 for after job change.
The 40 and 60 series Convertible and Riviera models will have stiffer rear shock absorbers available under Gr. 7.345 Part #5531428 and also new rear spring Gr. 7.503 Part #1174150 having heavier load capacity.
The 50-70 series Convertible and Riviera models will use only stiffer rear shock absorbers Gr. 7 .345 Part #5531427. No change is being made in series 50 and 70 front springs.
NOTE: Changing the rear springs on 40-60 series cars will not have any noticeable effect on trim height.
FRONT TIRES RUBBING ON FRAME
Some of the first production Buicks were shipped out with too much turning angle on the front wheels. This condition, if not corrected, will permit the front tires to rub the frame side rail upon a full turn. Therefore, all cars delivered should be checked at 2000 mile inspection and all others should be checked at time of new car conditioning.
This condition can be corrected by installing a 1/32″ thick plain washer under the bolt head of the rear steering arm bolt on both right and left sides. See Figure 59.
In order to install the washer, it will be necessary to remove the hub and drum assembly to gain access to the nut on the rear steering arm bolt.
The washer under the steering arm bolt head reduces the turning angle of the wheel enough to eliminate the tire from rubbing the frame on full turns.
IMPORTANT: It should be noted that a check for tire clearance should be made after installing other than factory specified tires. Thus, extra heavy duty or safety tires such as Royal Masters or Double Eagle, etc. may not have proper frame clearance due to their greater size.
HOOD ORNAMENT CHANGE
Recently a change went into production whereby the hood ornament grill was changed from a screen type to a solid plate. This change was made because the air filter inlet is directly behind this grill and it is very susceptible to foreign material. Although no difficulty has been experienced with the first type, the change was made only as a precaution.
GAS TANK DOOR BUMPER CHANGE
Re-drilling of Attaching Holes for Installing Gas Tank Door Guard No. 981542 on 1956 Series 50 Cars
Due to a change in location of the Gas Tank Door Bumpers on 1956 Series 50 after- job cars, it will be necessary to re-drill the bumper attaching holes when installing a gas tank door guard.
To properly locate these holes, remove the two screws and bumpers and place the door guard in position. Mark the location of the holes on the fender through the holes in the door guard. Remove guard, centerpunch and drill holes with a 3/16″ drill. Place guard back in position and install the rubber bumpers, adjust guard as necessary and tighten the screws.
This re-operation is necessary only on 50 Series cars and does not apply to other models.
HOOD SAFETY CATCH
Following is a reprint of Special Red Band Service Letter, Dealer No. 165 dated December 14, 1955, on Hood Safety Catch.
“We have received a few reports of hoods flying open on 1956 models due to misalignment of the hood safety latch and plate assembly. In order to prevent this, it is suggested that all cars be checked prior to delivery or when the car is brought in for service.
“This check can be made by releasing the primary latch and raising the hood while observing whether the safety hook catches the lower latch flange as it should or on the edge of the hood latch mounting panel.
“If the safety hook is engaging the edge of the hood latch mounting panel, as shown in View A, it will be necessary to bend the safety hook stops, as shown in View C, by lightly tapping the safety hook inward enough so that it will properly engage the lower latch and not the edge of the mounting panel. Correct engagement is shown in View B, Figure 60.
”This is not a campaign; however, it is important enough to check all 1956 cars that are in the hands of the dealer for service or pre-delivery.”
Following is a reprint of Special Red Band Service Letter, Dealer No. 168.
Effective immediately, all Flint and Kansas City built cars, built prior to approximately December 14, 1955, must be inspected to note the type of jack with which each car was equipped. All “R -H” jacks illustrated in Figure 61 are to be remove from service.
Figure 61 also dearly shows the differences in construction between all four (4) jacks which were used in production prior to December 14, 1955.
Up to that time approximately 19,000 cars (Kansas City and Flint built cars only) were equipped with the “R -H” jack and in order to determine which cars have them, it will be necessary to call in all owners of cars having serial numbers lower than these listed below:
Flint Assembly Plant: C1038673
Kansas City Assembly Plant: C4012550
All replacement jacks may be ordered from your Parts Ware house to take care of this campaign, including a new improved ”R -H” jack which is identified by an “X” stamped on the left side of the jacking lever, as shown in Figure 61. Replacement jacks are to be ordered under Group
8.820 Part #1392635, which does not include the jack handle; therefore, do not discard handle used with old jack. When jack orders are filled at the warehouse, any one of the other three (3) jacks (Walker, Universal and Auto Specialties) shown in Figure 61 or the new improved “R -H” jack (identified by the “X”) may be shipped. Please do not specify a particular make when ordering as orders are filled according to supply on hand.
All “R -H” jacks which are replaced are to be packaged in the carton in which the new jack was received and be returned to your zone M.R. Room properly tagged and accompanied with a separate AFA for each jack. Dealers will receive credit for material only.
GAS TANK DOOR GUARD INSTALLATION
The Rear Fender Side Moulding on some 1956 series 70 cars may be positioned too close to the lower edge of the Rear Fender Gas Tank Filler Door to allow adequate clearance when installing Gas Tank Door Guard, Gr. 8.210, Part #981759. If this condition should occur, it will be necessary to tap the moulding downward with a block of wood to gain clearance for the door guard. The fender moulding clip holes are large enough to allow the moulding to be re-positioned downward to get the needed clearance.
The location of the Gas Tank Door Bumpers were changed after production started and holes for both bumper locations are provided for in this Gas Tank Door Guard. However, in some installations the bumper screw holes may not exactly coincide with the holes in the Door Guard. lf this occurs, it will be necessary to center punch and drill new bumper screw attaching holes using a 3/16″ drill. After drilling new holes, place guard back in position and install the rubber bumpers, adjust guard as necessary and tighten the screws.
SPARE TIRE LOCKING ROD
We have received a few reports that it is difficult to remove the spare tire locking rod nut on some 1956 cars. This is due to the locking rod nut being installed too far down on the thread of the rod, thus preventing the use of the lug wrench.
If difficulty of this type is encountered in the Field, it is suggested to remove the locking rod from the upper hole in the body anchor bracket and install it in the lower hole.
FRONT BUMPER RATTLES
A few cases of squeaks or rattles which appeared to be in the front sheet metal of first production jobs have been traced to the bumper guard top flange extension contacting the radiator grill anchor bracket. See Figure 62.
These points of possible interference may be observed by raising the hood and looking down between the radiator and hood latch mounting panel.
If complaints of this type are encountered in the field, it will be necessary to remove the bumper assembly and cut the inner end of the top flange extension as shown in Figure 62.
This condition is more prevelent on 40-60 series cars, however, a few cases have been reported on 50-70 series.
GAS TANK RATTLE
We have received a few reports of rattles existing in the area of the gas tank. Upon investigation it was found that the gas tank gauge stand pipe was too long and strikes the bottom of the tank.
If complaints of this type are encountered in the field, the gas tank gauge unit should be removed and 1/4” be cut off the bottom of the stand pipe (inlet) as shown in Fig. 63.
This is being corrected immediately at the source and corrective measures have been taken in production.
REAR SPRING BOLT CONTACTING BODY
1956 Series 40-60
A few cases of the upper rear spring attaching bolt interfering with the body floor pan have been reported on 40-60 series cars due to insufficient clearance between frame and body floor pan. A change is being made in production to allow more clearance between the bolt and floor pan; however, if trouble of this type is encountered in the field, the installation of another washer under the bolt head should eliminate interference.
NOTE: Interference of bolt and floor pan can set up a vibration which may be mistaken as exhaust roar.
HUB CAP CLIPS
The Parts Department has released for service a new hub cap clip which is designed to eliminate the clip breakage problem presently encountered. The new clip will replace those previously used. Following are group and part numbers of clips involved.
Gr. 5.864 Part 1163410 Motor Wheel wheels
Gr. 5.864 Part 1166038 Kelsey-Hays wheels
To be replaced by:
Gr. 5.864 Part 1168043 Motor Wheel wheels
Gr. 5.864 Part 1168042 Kelsey-Hays wheels