[MD79TA]

My 68 has single piston calipers. I thought the 68 and I think 67 had a duel piston caliper? Could this be a late 68 with the 69 single calipers? Anyone else have this ? I know the car came with disc brakes as it listed on PHS. . Doug

[68pongto]

67 and 68 disc brakes were 4 piston, 2 on each side of the caliper. I doubt a 68 came with single piston disc brakes from the factory. Somebody probably just switched out the calipers and mount brackets years ago. There was a time when there were no rebuilt 4 piston calipers available from auto parts stores. Now there are aftermarket parts available and the Corvette brake places rebuild them. They are actually great brakes when properly maintained. What is the build date of your 68 on the trim tag?

[MD79TA]

Thanks for help. 05D68 is build date so don't know if that late or early? . It must have been replaced I guess when they were not available . I had a problem with replacing a flex line last year which is totally different and can not be inter changed. I had ordered from ames and I thought someone had told me that they had problem with the 67/68 design and lots of warrantee work so some either came or were replace with the 69 to. 72 single calipers. I am not changing back for a few reason but one is money. I just checked for a 68 4 piston 185 dollars . For the single piston 69 65 dollars. From what I have read neither are great but I would think the 69 /72 must have worked better. Doug

[MD79TA]

This was week 4, may 68 ? I think they change years in July so this would be late 68 model? Any one else with the single piston calipers on their 68? It sure looks like it was factory install. Doug

[Verdoro 68]

68 had 4 piston. They were known for being unreliable, hard to maintain and were difficult to get parts for until relatively recently. I'd bet someone swapped them out to single piston calipers. Easy swap for more common and reliable parts.

[68pongto]

4th week of May is somewhat late, but they made cars until the 3rd week of July. I doubt there would have been a shortage of 4 piston disc brakes 2 months before the end of production. I have cars with the 4 piston and single piston disc brakes. They both preform equally as well. I have not found my 4 piston disc brakes unreliable whatsoever on my GTO's or Corvette. I would think the main reason for the new 69 setup was that it was cheaper to produce. Think about it, what are all the new high performance Brembo brakes? 6 and 8 piston! If single piston was superior, why wouldn't Brembo make them that way?

[Greg Reid]

I too have been reading and hearing for years that the 4 piston setups were troublesome. My '68 came with drums but someone thankfully changed them to single caliper discs at some point over it's lifetime. One of the few good things a previous owner did to it.

[MD79TA]

They did have a lot of problem with the 68 4 piston brakes if you do some searching on google lots of leaks and shortage of parts. I just wonder if they swap over towards the end or maybe on a warrantee program they replaced. I do know that it's not a difficult swap caliper/ brackets/ rotors and flex hose but I guess I will never know who did. It.I have a seize caliper on right side and I can get the single for 65 dollars vs the 4 piston for 165 plus core. I don't think it's due to performance . What I have read is much less problems with the single and better stoping power. I think they changed rotor to a lager one at same time, Doug

[MD79TA]

This is good info but does not tell if factory did any upgrade during 1968. Also I guess the rotor is smaller on 1969 but vented? Doug http://www.pontiacdiy.com/mastering-...s-brake-guide/

[Greg Reid]

From the above linked article-

For the 1969 model year, the braking system was revised somewhat. To help correct leakage problems and the resulting warranty costs, Pontiac came out with a new, simpler, front disc-brake system, which was optional in the GTO and other A-Bodies. It featured a new single-piston caliper and a slightly smaller 10.9-inch vented rotor. The pistons were also less prone to cocking and getting stuck in the bores. This system remained pretty much unchanged through the 1972 model year.

[68pongto]

The rotors are the same from 68 to 69. They were the 2 piece design, they may have even carried them over on early 70's. The problem with the early brake systems was the surface area on the pistons. The 4 pistons had more area for corrosion. Nowadays they stainless steel sleeve them. DOT 3 brake fluid to this day still absorbs moisture, and it is recommended that you flush your brake system and fill with all new fluid every few years, but who ever really does that?

[PurelyGTO68]

Originally Posted by MD79TA

This was week 4, may 68 ? I think they change years in July so this would be late 68 model? Any one else with the single piston calipers on their 68? It sure looks like it was factory install. Doug

Correct. 05D is 4th week of May 1968. Same week my car was started. The disk brakes on my car are the 4 piston type so I think someone changed yours at some point along the way.

Looks like there might be date codes on the calipers. I actually have mine on the bench so I'll check when I get home. Are there date codes on your calipers?

[NEW64OWNER]

Originally Posted by 68pongto

The rotors are the same from 68 to 69. They were the 2 piece design, they may have even carried them over on early 70's. The problem with the early brake systems was the surface area on the pistons. The 4 pistons had more area for corrosion. Nowadays they stainless steel sleeve them. DOT 3 brake fluid to this day still absorbs moisture, and it is recommended that you flush your brake system and fill with all new fluid every few years, but who ever really does that?

Rotors are 11" from 69-72 and will interchange with the earlier 2 piece type. The problem wasn't surface area, it was where they placed the O ring (on the piston) which meant the cast iron bore of the caliper body was the surface that the o ring sealed against, well guess what cast iron rusts and gets pitted so that's why all the early 4 piston calipers would eventually leak. This was the Corvette design. Sleeving the 4 piston calipers solves this problem. 1969-72 single piston solved the leak problem by placing the o ring in the cast iron bore so the sealing surface was now the hard chromed surface of the piston, no more leaks.

[NEW64OWNER]

The factory never used 69 single piston calipers on a 68 car.

[Scott Thelander]

just for giggles

I think the 69 caliper has a shape of its own on the back by the hose fitting ..

and are very easily identified.... by the tall casting .....I can supply a picture of mine I have several dates and pairs

and the rotors change diameter in the middle of 70 somewhere... when they went to the 1 piece as stated earlier ....

look closely at the hose bracket to frame ... they needed to change the bracket out
because the hose ends are different,,between 4 piston and single hoses,, are your clips in there and the lines tight..any signs of tampering ?

the backing plates need changed out .... too ...

here is a big clue ..... look at the caliper bolts going to spindle closely ... do they look disturbed ...

just my nickles worth ........

Scott

[MD79TA]

I have look closely at them and all looks original. As you stated I had a problem last year on the flex hose. After getting one from Napa and then one from Ames I realized something was wrong. I called Ames and they told me they have had a few customers call with same issue and that I needed the 69 hose. Bingo it worked . That is why I asked if any one else had this. It really looks original , bracket, hose, clips, back plate but who knows the car is almost 50 years old and could have been swapped a long time ago. I am buying calipers, pads, rotors and wheel bearing Monday for both sides. Not sure on where yet. . Doug

[NEW64OWNER]

Originally Posted by Scott Thelander

just for giggles

I think the 69 caliper has a shape of its own on the back by the hose fitting ..

and are very easily identified.... by the tall casting .....I can supply a picture of mine I have several dates and pairs

and the rotors change diameter in the middle of 70 somewhere... when they went to the 1 piece as stated earlier ....

look closely at the hose bracket to frame ... they needed to change the bracket out
because the hose ends are different,,between 4 piston and single hoses,, are your clips in there and the lines tight..any signs of tampering ?

the backing plates need changed out .... too ...

here is a big clue ..... look at the caliper bolts going to spindle closely ... do they look disturbed ...

just my nickles worth ........

Scott

Both of your calipers are incorrect for 69 A body. The first picture is a 1969 Camaro/69-74 Nova. The second picture is a later then 72 A body, 73-77

[MD79TA]

Scott picture are not close to the ones on mine either . Doug

[Scott Thelander]

my 82000 mile judge had a swap at one time because thats one of the calipers
I had taken off that car

and the other is from my 90000 mile 72 442 when I did a brake job on it

crazeee

thought they were original too

['ol Pinion head]

a few comments in an attempt to clear up a few things that have been written above.
totally agree the factory 4 piston disc calipers were problematic, have dealt with several sets, & have shipped out many rebuilt original '69 single piston calipers, original caliper brackets, & dust shields, just so '67 & 68 guys could get away from leaking 4 piston calipers. Performing a proper restoration, I would get ahold of White Post to properly resleeve & rebuild the factory 4 piston calipers.

-GM A-bodies with factory disc brakes used original 2 piece rotors from '67- mid 70 production. The same "2 piece" rotors were also originally used on '69 & early '70 GP's, as well as all '67-69 F-body's with factory discs, also on early Novas equipped with factory disc brakes.

For many years, I specifically searched out nice thick original "2 piece" rotors. Many made it back on to some very detailed restorations of some very collectible performance Pontiacs & Chevrolets, many to occasional members of this site. On nice clean original '69-72 style caliper brackets, there is a part number inscribed, as well as a date stamping. Have sold & shipped out many many original caliper brackets, of which, for many years, saved the very best & had them replated.

Wheel offset differences... when Pontiac went from "two piece" rotors to the "one piece" aka integral rotor, the 1970 Pontiac A-body's factory optioned with 14x6 rallyII's went from JL coded rally II's to the JT code rally II's. Chevy on their Chevelles, at this time, went from YA coded 14x7 SSI's to AO coded 14x7 SSI's. Am not a '70 Nova guy, but would bet at this time, Novas factory equipped with this same Super Stock I wheel, also changed from YA's to AO's as the line changed from "2 piece" rotors to the integral rotors.

-due to the different "height" of the rotors, & different offset of these wheels, the track of the front & rear axle changes slightly when one uses the common parts store "one piece" rotor with the earlier coded wheels.