dual or 4 piston calipers
#1
dual or 4 piston calipers
Had a guy ask me today about 68 & 69 442 optional dual piston and 4 piston calipers. I was totally lost because I didn't know there was a dual piston caliper optional on these cars never mind 4 piston. He wanted to know if I knew anything about a 4 piston caliper. He was positive they made dual piston calipers but was curious about 4 piston. Any of you guys verify or have info on this?
Thx
Thx
#2
1967 and 1968 disc brakes were 4 piston there was no dual piston. There are 2 pistons on the inboard side of the caliper and two pistons on the outboard side of the caliper. The two sides are connected through a short metal brake line. This was a similar design to the corvette brakes that came out in 63. In 69 the caliper was changed to the single piston design I assume due to cost savings but I am not sure. I have a set of 4 piston brakes on one of my 67 GTO project cars. These systems were basically the same across A and F bodies and only used in 67 and 68. This design uses a two piece rotor design that was very hard to find until they started reproducing them a few years ago. My 68 Toronado uses a very similar design but while the A and F body cars use 11 inch rotors, the E body cars use a 12 inch rotor. The 67-68 two piece E body disc brake rotors are VERY difficult to find if you need to replace them. Here is a pic of my Toro disc brake setup. For the A body, imagine a slightly smaller rotor and no axle coming through the center.
#5
Yes disc brakes were fairly rare in 67 and 68 so most don't realize they were 4 piston. Just about everyone who adds a disc brake upgrade to a 64-68 A body uses a 69-72 single piston set up as they are readily available as used "take offs" and new after market and will bolt right on.
Last edited by Loaded68W34; October 25th, 2020 at 05:39 PM.
#6
1967 and 1968 disc brakes were 4 piston there was no dual piston. There are 2 pistons on the inboard side of the caliper and two pistons on the outboard side of the caliper. The two sides are connected through a short metal brake line. This was a similar design to the corvette brakes that came out in 63. In 69 the caliper was changed to the single piston design I assume due to cost savings but I am not sure. I have a set of 4 piston brakes on one of my 67 GTO project cars. These systems were basically the same across A and F bodies and only used in 67 and 68. This design uses a two piece rotor design that was very hard to find until they started reproducing them a few years ago. My 68 Toronado uses a very similar design but while the A and F body cars use 11 inch rotors, the E body cars use a 12 inch rotor. The 67-68 two piece E body disc brake rotors are VERY difficult to find if you need to replace them. Here is a pic of my Toro disc brake setup. For the A body, imagine a slightly smaller rotor and no axle coming through the center.
#7
The Toro stops great! The dust seals were torn on the original calipers and the pistons had some pitting so I put on a rebuilt set (still have the originals). I also made all new steel lines for the whole car (a few months after I finished the car I saw that inline tube came out with brake line kits for these cars) and rebuilt the original proportioning valve (small cylinder mounted on the passenger side of the master cylinder) using parts from a reproduction 67-70 A body valve. The castings are just slightly different between the A and E body valves as far as the way they mount. The rear hold off valve for these is on the outside of the driver side frame rail just behind the front wheel well and just needed cleaned up.
#9
#11
1967 - 1968 Factory Disc Brakes were Four (4) piston caliper set ups ONLY.... There is No such anything else in 1967 - 1968. And in 1969 , they all became single piston calipers.
Full Size cars, and A Body cars both had a very small percentage of vehicles that had factory Disc Brake Set Ups..... Both very different.
And the Tornados were different yet again.
And incidentally -- I have N.O.S. +++ Asbestos +++ Brake Pads for All of these --- which are
+++ Critical +++ such that you don't RIP UP these Rotors to smithereens..... Because all of those Rotors are virtually "Unobtainium".......
Always best to simply call me --- Craig --- 516 - 485 - 1935.....
Full Size cars, and A Body cars both had a very small percentage of vehicles that had factory Disc Brake Set Ups..... Both very different.
And the Tornados were different yet again.
And incidentally -- I have N.O.S. +++ Asbestos +++ Brake Pads for All of these --- which are
+++ Critical +++ such that you don't RIP UP these Rotors to smithereens..... Because all of those Rotors are virtually "Unobtainium".......
Always best to simply call me --- Craig --- 516 - 485 - 1935.....
#14
Not sure if the Olds calipers, were designed like the Corvettes, but I had Vetts 30 40 years ago, and every one sooner or later, leaked, because of rust, and had to have stainless steal sleeves, in them, and that cost about $400- 500 then, not sure what it would cost now? Wondering if that is why Olds changed the design, so they would not have a warranty problem?
#15
The "Corvette" 4-piston calipers were responsible for kick-starting the aftermarket performance-brake industry. They got their start shoving stainless-steel sleeves into failed/seized 4-piston calipers, and grew from there.
Far as I know, Corvette, Camaro, A-body used Delco 4-piston calipers.
I think the Toronado/Eldorado, and perhaps the B- and C-bodies had Kelsey-Hayes 4-piston calipers. Thus the difference between the Toro calipers having the fluid transfer tube while the others were just drilled internally.
At any rate, just about everything except 'Vette and maybe the Camaro option, dropped the rigid-mounted 4-piston calipers for the '69 model year. After that, it was single-piston, floating caliper.
Last edited by Schurkey; October 27th, 2020 at 11:26 PM.
#19
#21
The brakes on the 77-90 B-body cars use exactly the same 10.75" rotors and D52 calipers with exactly the same pads and the same 2.9" piston as were used on the 69-72 A-body cars. Any difference in braking force has to come from some other problem.
#22
Low stopping power. I was able to get a small screech and a harder stop with my old calipers. Now it just feels soft (but not in a "needs to be bled/adjusted" way.
#23
Loose wheel bearings in front
Glazed or low-friction (poor quality) pads/shoes
incorrect master cylinder-to-wheel cylinder diameter ratio
Partially-seized calipers
Failing brake hoses
Failing master cylinder
Overly-tight park brake adjustment
Failed brake booster (I had this problem on TWO early-'90s Luminas) In both cases, the booster "tested" good via the usual methods--there was just very little assist.)
No doubt there are other factors that would cause similar symptoms.
Last edited by Schurkey; October 29th, 2020 at 09:28 AM.
#24
Loose wheel bearings in front
Glazed or low-friction (poor quality) pads/shoes
incorrect master cylinder-to-wheel cylinder diameter ratio
Partially-seized calipers
Failing brake hoses
Failing master cylinder
Overly-tight park brake adjustment
Failed brake booster (I had this problem on TWO early-'90s Luminas) In both cases, the booster "tested" good via the usual methods--there was just very little assist.)
No doubt there are other factors that would cause similar symptoms.[/QUOTE]
Yep. Assuming everything else was new (due to the spindle swap), then my first reaction was different pad composition as one more variable in the system.
#26
That plus stainless lines that don't rust helps. I was asked by a customer once " where does the moisture come from", the simple answer is heat from braking. You heat up the fluid and it cools, you now have condensation in your system. Bad for any ferrous parts. I have had the synthetic fluid and stainless lines on for ten years now and the fluid is still clear, not red like old alcohol based fluid. It is something to look into if you want to avoid a rusty brake system and brake fail.
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