......Camaro- Untold Secrets125.gif (824 bytes) Feature Article
 

Special intent and high intrigue make this Camaro performance option one of the most impressive on the list.

Camaro enthusiasts tend to agree, the four wheel disc brake system remains one of the most popular, impressive, and highly prized high performance options available for the first generation Camaro...


MOST UNCOMMON....

Unlike today, in 1969, Corvette was the only mass produced American car to use four wheel disc brake technology which made the concept new and exotic. Needless to say, when the four wheel disc brake system became available on the 1969 Camaro as regular production option- RPO JL8, it was a remarkable occasion!


SPECIAL INTENT...

Prior to its' release as a regular production option, the four wheel disc brake system was available "over the counter" through the Chevrolet parts department as a "Heavy Duty Service" option beginning March of 1968 (see Photo below).


Photo above shows service package disc brake rear axle on 1968 Camaro Z/28..


This in itself is significant, although somewhat ambiguous, the term "Heavy Duty Service" was Chevrolets catch all phrase meaning: "intended for racing". Factory production and availability of this optional equipment at the consumer level was actually a secondary consideration.
Chevrolets primary objective was to develop an advanced brake technology for the PENSKE/SUNOCO TRANS-AM race team in effort to make the Camaro a more formidable competitor on the road race circuit.

Production for the general public was actually the result of a concession made by Chevrolet to satisfy the FIA/SCCA rule which stated, that all optional equipment used on the SCCA sanctioned race cars must be made available to the public in specified quantities. Therefore, to comply with the rule and keep Chevrolet's cost down, the four wheel disc brake system became a "limited production" service option.
The spin off benefit of this race bred technology was that it was now destined for the average Camaro owner, who due to a special set of circumstances would now be able to "upgrade" his 1967-68 Camaro using factory "racing" equipment. So, upgrade they did, and why not? After all, it was listed as optional service equipment, developed specifically for the Camaro, available through Chevrolet and therefore "correct" AND legal to do so... then and now, just as Chevrolet it intended it to be!


JL8 Front system JL8 Rear system

 

This 1969 Camaro Z28 shows one of the best examples of a correct and well detailed RPO JL8 system...

 

 



OPTIONS WITHIN OPTIONS...

Until the introduction of the 1969 model, Camaro owners were limited to upgrading their brake systems by using the Heavy Duty Service Package. Things changed dramatically with advent of the 1969 Camaro and the introduction of the RPO JL8 four wheel disc brake package. The Camaro owner now had the option to order his 1969 Camaro with four wheel disc brakes (RPO JL8) installed at the factory or with base equipment and later upgrade to four wheel disc brakes using the HD Service Package.

Shown below is the "basic" HD service package disc brake rear axle housing assembly. Note the Corvette caliper adapter/park brake assembly's...

Taking it a step further... If he ordered the optional JL8 equipment on his 1969 Camaro, he then had the additional option to further upgrade the system by substituting the heavy duty rear axle from the previously released HD Service Package in place of the JL8 rear axle. The advantage in this being; the HD Service Package axle uses larger diameter axle shafts and bearings which significantly improve durability, a factor especially important in racing. Anyway you went, it was a win-win situation with this limited production performance equipment.

JUST HOW LIMITED?....

Unfortunately, there is no official number that accurately reflects the total production figure of the Camaro Heavy Duty four wheel disc brake Service Packages. These packages were made in short "off line" batches and not well documented.

The 1969 RPO JL8 on the other hand enjoys one of the lowest production figures of all 1969 Camaro options because of its "inherent" limited production and availability during the 1969 model year. Officially, Chevrolet submitted an "arbitrary" production figure of 206 units. This figure however, may have been intentionally inflated in order to satisfy the FIA/SCCA minimum requirement when filling out registration forms for homologation of the Camaro and its optional equipment with the FIA/SCCA sanctioning committes.

1969 RPO JL8 QX Coded disc brake rear axle assembly. Code indicates this is a 3.73:1 ratio, Built May 14, 1969.


Of the assumed 206 takers, most were thought to be some where between serious road racers and the occasional amateur weekend racer who appreciated state of the art high performance components. The JL8 option was canceled 7-16-69, short of a full years run and was frequently unavailable due to infrequent batch runs of production pieces, more specifically the rear axle assemblies.


RPO JL8 AVAILABILITY AND COST...

RPO JL8 was available on all Camaro models and was considered to be a "high dollar" option, ranging from $500.30-$623.50 depending on the model it was ordered with. The relatively high cost of the option may have been prohibitive for some and may also have been a contributing factor in keeping the total sales figure low.
In contrast... Current research shows that a fully documented Camaro with the factory equipped RPO JL8 option will sell now for $10-15K over a comparable Camaro without the JL8 option!


WORTH IT?....

A question not easily answered. However, in an attempt to find an answer, lets first understand what influences price. SUPPLY AND DEMAND! Supply we already know is extremely low and demand is extremely high. Why?..
The low production figure intrigues many collectors as do the esthetics. The presence of the four wheel discs on the early Camaro tends to have a drop dead, heart stopping effect on those who see it! Enticement may also come from the more obscure and esoteric legend and lore associated with the race bred heritage, leading us to the more practical part of this quotient, performance!


KILLER PERFORMANCE!....

Performance of the four wheel disc brake system is subject to and contingent upon its level of preparation. Much like the blueprinting of an engine, the careful selection of components along with their proper set up and maintenance, all have an effect on the level of performance. A properly prepared system such as Penske used in the '68 and '69 seasons were and still are extremely competitive systems capable of stopping a relatively heavy "sedan" repeatedly with out failure in extreme racing conditions.

What the four wheel disc brake system was capable of performance wise as it left Chevrolet was the subject of a few period magazine tests, two of which were, CAR LIFE, August 1969 (RPO JL8), and CAR AND DRIVER, July 1968 (HD SERVICE PACKAGE). Briefly, the four wheel disc brake system was shown to be a marked improvement over the RPO J52 (power asst. frt. disc/rear drum) not only in the area of stopping distances but also in terms of resistance to fade. It should be remembered however, that each JL8-Service package equipped car is unique having its own individual built in characteristic differences due to variances between equipment, weight and distribution factors. Therefore, brake performance will also vary between vehicles.
The tests that were conducted by the magazines were light weight compared to the first "Durability and Effectiveness" test of the four wheel disc brake system conducted at Chevrolet's proving grounds.
On 10-30-67, Gib Hufstader, as engineer in charge of development, requisitioned an engineering test on an all disc system he put together on a 1968 Z/28 Camaro. The system used the Corvette HD J56 calipers front and rear, no proportioning valve, dust shields, scoops or deflectors. Test conditions were pretty severe, they ran a "Sebring Schedule" requiring the driver to brake at a steady 25 FPSS on the decelerometer from 145 MPH to 45 MPH at one mile intervals for four hours!
Not only did they hold up but at brake point 131 the driver notes "They seem to be the same as at the start". Again, at brake point 145 driver notes "Very easy to hold pedal, it's capable of more deceleration". Finally at brake point 299 they begin to fade slightly and at the end of four hours had completed 318 repetitive applications from 145 MPH to 45 MPH and were still capable of 25 FPSS on the decelerometer!

BRAKE SPECIFICATION COMPARATOR 

CONSTITUENT: SERVICE/JL8 '67 RPO J52
     
POWER ASSIST YES YES
FRT. ROTOR DIA. X WIDTH 11.75" X 1.25" 11" X 1"
RR. ROTOR DIA. X WIDTH 11.75" X 1.25" N/A
RR. DRUM DIA. N/A 9.5"
RR. LINING WIDTH N/A 2.0"
TOTAL SWEPT AREA 461.2" 332.4"

THE FINAL RESULT...

As it turned out, the four wheel disc brake system is recognized as being one of the largest contributing factors responsible for establishing the Camaro as the 1968 and 1969 TRANS-AM champion and forever into the hearts and minds of Camaro enthusiasts...


More in-depth technical information on the Camaro four wheel disc brake systems can be found in the print version of "Camaro, Untold Secrets"...