indy front axle 2

The front axle and brakes on car #37

While the Ray Kuns article gave some information about the axles, there were some conflicting details in the description.  The front axle was supposed to be from a 1932 President Model 91; but, how could that be on a car built for the 1931 race?  The rear axle came from a GB or EW sedan, which I eventually learned made it from a 1928 model.  The race cars used a 3.07 ratio differential, which was available on the smaller Sport Roadsters and Victoria coupes but not the larger sedans.  The low numerical ratio was used with the slow-turning Big 6 engine.  On a race car with 7.00-18 tires having 32-inch diameter and 4000 rpm engine speed, this translates into 125 mph. 

My problem was to find a pair of axles and liberate them!  The particular car models that used the axles I wanted weren't built in large quantities.  Eighty years later, the few survivors were either restored cars or well-rusted lumps in some farm field.  Anyone who had collected and stored axles for a project was reluctant to part with them.  It took more than a year to find what I needed.

I tried to widen the scope of donors by seeing what other models might have used what I needed.  Studebaker owners are among the fortunate few when it comes to available documentation.  The Studebaker National Museum archive in South Bend, IN, holds 70 tons of drawings and related materials.  Archivist Andy Beckman now has a newly renovated building to house this collection and he can locate original drawings for many parts.  He was able to extract the drawings for three front axles to cover the period from 1928-1933, a time of great transition in Studebaker technology.  The drawings are at full scale showing one half the axle, so these are big sheets.  The 1928-29 and earlier cars had 4-wheel mechanical brakes actuated by steel rods linked by levers and cross-shafts to the brake pedal. On the front axle, a small tower supported a bell-crank to force the brake shoes apart within the stamped steel drums.  By 1930, the actuators were cables that ran directly to the backing plates.  The year 1933 was the last year of the huge 337 cubic inch straight 8 engine and the first for hydraulic brakes.  Additionally, the 1933 axle was several inches wider to improve the stance of the cars.

I was able to determine from the drawings that the 1929-30 front axle was identical in all dimensions to the 1931-32 axle except that the older axle had the two small towers for the bell-cranks.  In a fortunate moment, Bob Munter, proprietor of WCD Garage in Northboro, MA and Studebaker restorer extraordinaire, was scrapping a chassis from a 1929 President FH sedan.  I bought the front axle, which came with two wood-spoke wheels and a couple of shock absorbers.  The steering box and steering wheel came with the axle.  I brought them home on my trusty 16 ft car-hauler trailer.
Indy car front axle
Front axle with wheels, tires, brakes, and steering gear.
brakes from 1929 FH
Rod-operated brakes on 1929 President FH front axle.  I'll grind off the small towers that support the bell-cranks.
chassis with front axle
Here is the front axle with the chassis (left).  You can also see the 58 lb flywheel, a couple of shock absorbers, the aluminum cylinder head, and the steering gear.

Heavy does not begin to describe these parts!  Pity the person who had to change a tire in the "good old days".  The tire was mounted on a detachable rim that was held to the spoked wheel and its brake drum by a set of small blocks.  Even so, the tire and rim weighed an incredible 73 pounds.  The wheel and drum assembly weighed 48 lbs, backing plates and shoes came in at 26 lbs, and the axle itself, with tie rods, at 90 lbs.  That made 384 lbs (plus the springs) of unsprung weight on the front alone, leading to a poor ride and heavy steering.  

The President brakes were 15 inches in diameter and had three shoes.  The original race cars replaced the brakes with cable-operated 12-inch ones from the lighter Dictator series cars.  The Dictator and President brakes used stamped steel drums which went from cylinders to bell-shapes when they got hot.  It has been said that the Indy cars had just enough brakes to get them off the trailer.  During races at Indianapolis and other oval tracks, the brakes were only used when coming in for a pit stop, so it may not have mattered much - except when another car hit the wall or spun in front of you.  Lots of dependable stopping power was not what those mechanical brakes provided. 

Following the lead of Mike Cleary and his #18 car and August Grasis Sr. and Jr. with their #34 car, I decided to put on hydraulic brakes.  Because of the large size of the steering knuckles in front and axle housing in back, 12-inch brakes are needed to provide clearance, as well as replicate the look of the original cars.  Buicks used 12-inch brakes from the late 1930s well into the 1970s on the full-size cars like the Invicta, Riviera, and other models.  Shoes, wheel cylinders, springs, etc. are all easily and cheaply available for the 1960s cars.  I found a set of rear backing plates from a 1961 Invicta sedan and front backing plates from a 1963 Riviera on Ebay. 
Of course, the Buick backing plates don't fit the Studebaker axles because of the knuckle and rear axle housing size.  Big holes had to be machined in the backing plates for clearance.  Additionally, the backing plates weren't flat where they needed to mate to the axles, so I had some adapters laser-cut from 3/16-inch thick steel sheet.  These adapters are welded to rear surfaces of the Buick backing plates with some additional holes in the Buick plates to allow access to the mounting bolts in the adapters.
Buick front brake parts
Backing plates and aluminum drum from 1963 Buick Riviera next to 1929 Studebaker front axle.
front adapter plate
Adapter plate laser-cut from 3/16-inch steel on front knuckle.  Opening was 3"x7".

With Ebay as my prime supplier of brake parts, I also acquired four of the rare iron-lined aluminum drums from 1960s Buicks.  These will accommodate the 2.25-inch wide shoes up front and 2-inch wide shoes in back to provide the stopping power I want.  While it's true that finned aluminum drums are not original, on this issue I'll choose safety over original appearance.  If they look too flashy, I can always replace them with Buick iron drums, as are now used on the three Studebaker cars that still race.

While the shoes will clear the front knuckles, the hydraulic wheel cylinder is located too close to the spindle to allow it to be in the normal position above the spindle.  The front backing plates will be rotated 90 degrees to the rear to gain clearance for the wheel cylinder.  This will require that the entire brake assembly be removed from axle for bleeding the cylinder, but this operation won't be required very often.


The search for the rear axle was a long one.  What I needed was only in production a year or two circa 1928 and only used on part of the Studebaker range of cars.  The 1927 cars were set up for an external contracting brake on the rear axle and I wasn't sure if the flange bolt pattern would work with modern backing plates.  Rick Peterson had a 1927 axle in Los Angeles, and I even managed a business trip out there so I could see it.  But, it wasn't quite right.  One day, a 1928 Studebaker was offered on Ebay by a junkyard in Ohio.  The car was just a rusted jumble of parts, but there, sitting on the back of the remains of the frame, was an axle that looked like what I wanted.
1928 GB-W sedan remains
The 1928 Studebaker GB-W "sedan" as offered on Ebay.  At some point, it had been converted to a flat-bed farm truck but even that had been left to rot.

1928 GB-W rear
The rear axle, backing plates, and drive shaft which I obtained.

The junkyard was trying to sell the engine for $500 - and it may still be on Ebay - but, I called them and negotiated a deal for the rear axle.  It had a 3.31 ratio, a little higher than the original cars, but perhaps better for road driving and vintage racing.  Maybe I'll only get to go 115 mph.  A freight company picked it up in Ohio and delivered to the loading dock where I work.  I brought my trailer and hauled it home.  Fortunately, my engine hoist could be maneuvered into position to haul it out of the trailer.  I wanted to weigh the axle, engine, and all of the other parts for the car, so I bought four cheap bathroom scales at Walmart.  With three of the scales under the ends and the differential, the total came out to 175 lbs. 

George Hull, who assists August Grasis with the care and feeding of the #34 car, sent me a number of photos of the rear axle from when he had it stripped for overhauling.  The pictures showed some of the subtle modifications needed to adapt hydraulic brakes to the axle.  August and George had used Dexter 12" trailer brakes, as used on travel and boat trailers, but found that the linings needed to be a better grade for racing.  As with the front axle, the hydraulic wheel cylinder needs access for the bleeder and hose, so a couple of notches have to be cut into the axle flange.  To clear the large hex-shaped end, the backing plates and adapters have to have a 5.5" diameter hole, much larger than on modern backing plates.  An advantage of using modern backing plates is being able to have parking brakes.  This will make it easier to get the car registered to be street-legal some day.

rear axle housing #34
Rear axle housing used on car #34.  Note added notches for wheel cylinder bleeder and hydraulic hose.

George Hull with #34
George Hull with Studebaker Indy car #34.  This car, once owned by Brooks Stevens, has the 1933-style body and modern hydraulic brakes all-around.  August Grasis, Jr. drives the car in vintage race events.

As with the front axle, an adapter plate was laser-cut from 3/16" thick steel.  The adapter will be welded to the 1961 Buick Invicta backing plates and the assembly will be mounted on the axle.  The axle shafts will need to be cleaned up, perhaps the threads chased.  All new bearing cups and cones will be installed - would you believe that Rock Auto stocks at least half of them for $10-$15 each?  A little backlash adjustment, a little paint, and the axle will be good for another 80 years.

rear axle 1928 and frame
Rear axle placed under the new race car chassis.
rear brake adapter plate
Rear adapter plate before welding.  Laser cutting produced tight tolerances (+/- .003" or better) so that no additional machining was required.

TO BRAKES - part 2