REAR AXLE FILLER PLUG BREAKAGE
Fig. 59 illustrates the first and after production rear axle filler plug. (Rear axle filler plug and gasket kit, Gr. 5.400 No. 1390882). Due to occasional breakage of the plug head from the threaded shank, it is felt that this .plug should be replaced with the heavier, after production filler plug on all 1953 Buicks when they are in for service.
All personnel connected with the servicing of the rear axle should be informed of this change.
REAR AXLE SERVICING
The latest D.O.T. slide film release entitled “Servicing the Rear Axle” has a reference in it to the special rear axle cover to convert a 3 pint capacity axle to a 4 pint axle.
For information purposes, we are repeating that article below:
”In the near future, the rear axle housing cover will be replaced in production by the cover used during 1951. This cover has a higher filler plug hole location which increases axle oil capacity approximately 1 pint.
The increased quantity of oil appreciably reduces axle operating temperatures at high speeds and also assists in reducing early gear and bearing wear. The additional oil capacity insures a constant supply of oil in the bottom of the housing when taking high speed turns.
Whenever axle trouble is experienced with 1952 cars and the job is tom down for service, we recommend installation of the 1951 type axle housing cover and plus assembly, Group 5.398, Part No. 1390887.”
NEW REAR AXLE CARRIER
A new rear axle carrier and housing which will enable the use of faster rear axle ratios has been released for 1953 and will be in production on or about March 1, 1953. The pinion setting dimension in these carriers is changed from present production settings.
Figures 60 & 61 illustrate the difference between the old and new rear axle carriers. Figure 60 is the new carrier, Figure 61, the old.
Following are the “Service Instructions” and tables of part numbers used with the new rear axle and its corresponding speedo gears.
The change to rear axles using the new carrier and transmissions containing 8 tooth speedo drive must be simultaneous to obtain correct odometer gear combinations.
Transmission assemblies affected by this change are identical with previous type except for speedo drive gear. On Dynaflow units, the code number mark when the change starts is to be recorded for ail series. This mark will serve as a permanent identification in addition to the part number tag. Synchromesh transmissions will be identifiable only by part number, as no coding is used.
Transmissions stocked for service may be of either type as long as proper provisions are made to clearly identify the part number of the assembly, and to insure that correct speedo gear combination is obtained for the axle ratio used. This latter may be accomplished on transmissions having 8 tooth speedo drive by using an appropriate speedo pinion for the axle ratio used, or by installing the correct speedo drive worm for use with the original speedo pinion. The number of teeth on the worm can be counted in the transmission assembly if necessary by looking in the speedo drive shaft fitting hole with a good light, marking a tooth lightly on top as a start, then rotating the universal joint or main shaft slowly.
It is necessary that none but 8 tooth speedo drive be used with axles having the new carrier, because only the 8 tooth worm can give proper speedo combinations for all axle ratios used in the new carrier.
For service, the 7 tooth worm is to be installed in transmissions used for cars with the previous type carrier in the axle.
The new differential carrier is distinguished externally from the old carrier by 2 features easily visible:
- Middle rib is straight with no cut out for lock screws. (See Fig. 60)
- Lock screws are rotated; bottom screw is no longer straight down. (See Fig. 60)
None of the new axle parts are interchangeable with parts of the previous type axle, except as complete assemblies.
Pinion setting gauge dimension for all pinions after this change will be 2.980 from centerline of pedestal bores instead of 2.918. This does not affect the interchangeability on part numbers 1338327 pinion 41-10 ratio, or 1338126 pinion 43-11 ratio when used with 1328933 or 1338125 ring gears respectively, but will require use of the proper gaging dimension.
For service, pinion settings gauge readings for nominal setting are changed as follows:
Type: Gauge J-681A – Gauge J-2197
Old type pinions: .379 Nominal – .802 Nominal
New pinions: .317 Nominal – .864 Nominal
There is sufficient difference between the old and new settings to readily tell in any case which nominal setting to use for either gauge.
For setting ring gears in the new carrier, backlash is to be adjusted for not less than .006 or more than .011, with .007 to .009 preferred. Side bearing preload is to be 2 to 3 notches tight. One notch in the adjusting nut gives .005 movement along the cross bore axis, and represents about .0035 change in backlash. Differential cap bolts are to be set to 100-120 pound -feet torque at assembly.
PART NUMBERS OF NEW RATIO GEARS AND GEARS REQUIRING THE NEW SETTING DIMENSION:
TABULATION OF OOOMETER RATIOS FOR NEW AXLE RATIO
1953 FIRST JOBS
1953 AFTER JOBS (46539)
TABULATION OF AXLE RATIO USAGE REVISED TO LATEST EXPORT AND DOMESTIC RATIOS
1953 FIRST JOBS
1953 AFTER JOBS (NEW CARRIER)
PINION GAUGE CLAMP
1953 WIDE SADDLE REAR AXLE HOUSING
As of March 1, 1953, a new rear axle carrier and housing, which enabled the use of faster rear axle rations, was released.
Due to this change in rear axles and gears, the ring gear saddles in the new rear axle housing are approximately 11/16 of an inch wider than those in the old style. Because of this dimensional change, the clamp which holds the paddle to the pinion gear face (See Fig. 62) does not fit on the new style carrier saddles.
Kent-Moore has given July 1st as the delivery date for an adaptor kit which will include a new gauge adaptor and adaptor bar (universal clamp J 2197-15) that can be used on both the new and old style carriers. The new gauge adaptor will have a greater scribing area. Order blanks will be furnished to the dealers through the Zones.
It is suggested, therefore, that the present clamp be reworked and used as shown in Fig.63 until the new one is available.
This can be done by merely cutting out the stock between the holes and end of clamp. When securing the reworked clamp to the wide saddles, the bolts used should be equipped with large, heavy washers. (See Fig. 63)
It is cautioned that the pinion gear paddle be properly centered on the pinion gear and the set screw partially tightened before the clamp bolts are tightened. This is necessary as the reworked clamp must now be centered due to the slotted bolt holes.
PINION SETTING ADJUSTMENT
It has been called to our attention that there is some difficulty in the use of the new pinion setting gauge and/or adapter. If the instructions below are followed there should be no difficulty in the use of the pinion setting gauge.
Before the pinion setting gauge is installed, check the ends of pinion teeth for burrs or marks. If there are any present they should be stoned off; also rub stone over etched markings on end of pinion to remove high spots. The gauge adapter must seat flatly and firmly against ends of pinion teeth in order to obtain an accurate micrometer reading.
Install adapter with clamp and the micrometer gauge as shown in Fig. 64.
The adapter must be firmly held against the pinion by the clamp. The micrometer gauge must be firmly seated in the differential bearing seats in the carrier, with the micrometer spindle at 90 degrees to surface of adapter.
The pinion setting is obtained by adjusting micrometer until the spindle just touches the adapter, then reading the micrometer. IMPORTANT: Swing an arc with the micrometer spindle while adjusting, to feel the exact point at which it contacts the adapter. This point will be at the center or the high point of the arc, the correct position for taking the reading.
To obtain the proper reading, it is sometimes necessary to shift the position of the adapter off center with the pinion so that the spindle of the micrometer will be at the approximate center of the ground surface of the adapter and at 90 degrees with the surface.
REAR AXLE PINION BEARING OIL SCOOP
The offset of the rear axle ring gear when using the 3.6 and 3.9 ratios in the 1953 new wide carriers is so great the sling -off of oil from the ring gear does not line up with the oil passage to the pinion bearing. This results in a reduction in the flow of oil to these bearings.
A scoop has been designed which can be attached to the carrier and will direct more oil to the pinion bearings. The oil scoop is available in a rear axle oil scoop kit Gr. 5.506 No. 1391836 and should be installed in all 1953 cars having the wide carrier when installing new gears or bearings. In the future all wide carrier rear axle gear sets will include the oil scoop. The starting serial numbers for those jobs equipped with the new wide carrier are as follows:
40 Synchromesh No. 16832662
40 Dynaflow No. 16832729
52-72 No. 16832709
50-70 No. 16832588
except 52 and 72
The rear axle carriers may also be identified as first or after (wide carrier) as illustrated in Figs. 60 & 61 on page 48 of this Abridged Edition.
- Remove differential ring gear assembly.
- Remove pinion and drive shaft.
- Wipe carrier housing dry.
- Insert lip of scoop in oil passage and rotate scoop in oil hole until it is in the position as shown in Fig.65.
The scoop must tilt downward toward the oil passage hole to the pinion bearings in order to be effective. The back of the scoop should be as nearly flush with the surface of the carrier as possible.
NOTE: Screw hole should be located opposite top rib on front face of carrier in order to keep the drill from breaking through the case. If the drill should break through the back of the carrier case, before installing the screw to hold the scoop in place, it must be Permatexed. The Permatex will seal the screw and the hole in the case.
NOTE: Carefully remove all metal chips or dirt from carrier housing.
WHEN REFILLING THE REAR AXLE. THIS IS A PERMANENT REAR AXLE LUBRICANT AND SHOULD NOT BE CHANGED UNLESS IT BECOMES CONTAMINATED.
Time allowance for installation of oil scoop is .3 hr. in combination with any operation where the pinion and ring gear assemblies are removed.
PROPER REAR AXLE PINION SETTING
There has been some difficulty reported in the field in setting up replacement rear axle gears in ratios 3.9 to 4.1. Due to production change, the new rear axle pinions are 62 thousandths (.062) thinner than the previous type pinions. This thinner pinion is being used in past model ring gear and pinion replacement sets. If, after installation of the pinion there is a reading of 62 thousandths (.062) off the standard or old setting of .802 nominal (plus or minus the allowable error), use the gauge setting as the base setting and, if necessary, shim from that point to arrive at the proper NEW pinion setting.
As listed in this Bulletin, Page 49 Service Ring and Pinion Sets which includes Pinions No. 1338327 or 1338126 will require the new Gauge setting if manufactured after the described change was made.
The Gear Sets affected are as follows:
5.529 – 1393848 – Gear Set -Ring and Pinion (With Case) (3.9)
5.529 – 1393846 – Gear Set -Ring and Pinion (Less Case) (3.9)
5.529 – 1393769 – Gear Set- Ring and Pinion (With Case) (4.1)
5.529 – 1393767 -Gear Set -Ring and Pinion (Less Case) (4.1)
Any Parts received after approximately April, 1953 will have Pinions which will require the new setting dimension.
NEW OIL SEAL AND NUT
A new type pinion shaft oil seal has gone into production as of March 16, 1953. This new type seal has a revised outer retainer which provides more positive piloting during assembly, preventing cocking of the seal. Because of the slightly longer length of the seal retainer (See Figure 66), it was necessary to narrow the hex section of the pinion nut to provide adequate clearance over the new seal.
The revised nut Gr. 5.445, No.ll63542canbe used with either the new or old seals.
When replacing the pinion shaft oil seal in service the new seal and nut are handled as a kit (Gr. 5.445, No. 1393999). The new nut Gr. 5.445, No. 1163542 will also be serviced separately from the kit. It is cautioned, however, that the old nut cannot be used on the new seal.