By overeized metric calipers, I mean the near stock g body calipers with larger pistons like Speedway sells, not the LS1 calipers. It is claimed the oversized Speedway calipers produce more rotor torque than the Blazer brakes.
Blazer brakes vs oversized metric calipers
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I don't think any aftermarket caliper is low drag. I know what a low drag caliper feels like with a straight bore master but I wonder how a conventional calipers works with a stepped bore master that is used with a low drag caliper....
Any rebuilt or new caliper should be NON low drag, or normal calipers. They rebuild/build them to NON low drag (normal) standards so they can work with any master cylinder be it a strait bore or step bore. A LOW drag caliper cannot work well with a strait bore master cylinder as it cannot supply the volume needed on the first pump to fill the caliper. 1978-1981 "G-bodies" had NON low drag calipers and a strait bore master cylinder. 1982-1988 G-bodies had LOW drag calipers and a STEP bore master cylinder.
If your stock system is working as it should, good pads, resurfaced stock rotors, and a fluid flush will help out tremendously. From working with 2.75" bore calipers in the past, I don't see a lot of benefit especially if you are running a power boosted system. You money should be spent on good aftermarket pads , turned stock rotors, and a fluid flush.
People like the Blazer swap as it gives you a slightly larger rotor (10.75 v 10.5) and the dual piston calipers have a larger piston area than the stock metric caliper. I am almost certain that the S10 Blazer setup weighs more than the stock G-body setup as the caliper is also cast iron along with the caliper bracket.
That being said, the Blazer setup lends itself to easier big brake upgrades than the g-body spindle.
In my opinion, the step bore master cylinder is overly complicated, hard to bleed, and can lend itself to failure as it has more internal parts to make it work can fail. If you have one, replace it with the right hand drive 2000 S10, 1.0" bore master cylinder.
If your stock system is working as it should, good pads, resurfaced stock rotors, and a fluid flush will help out tremendously. From working with 2.75" bore calipers in the past, I don't see a lot of benefit especially if you are running a power boosted system. You money should be spent on good aftermarket pads , turned stock rotors, and a fluid flush.
People like the Blazer swap as it gives you a slightly larger rotor (10.75 v 10.5) and the dual piston calipers have a larger piston area than the stock metric caliper. I am almost certain that the S10 Blazer setup weighs more than the stock G-body setup as the caliper is also cast iron along with the caliper bracket.
That being said, the Blazer setup lends itself to easier big brake upgrades than the g-body spindle.
In my opinion, the step bore master cylinder is overly complicated, hard to bleed, and can lend itself to failure as it has more internal parts to make it work can fail. If you have one, replace it with the right hand drive 2000 S10, 1.0" bore master cylinder.
if a low drag caliper is rebuilt it is still a low drag caliper, the shape of the channel in the wall of the cylinder the seal sits in determines if it is a low drag or not. The conventional wall is 15° while the low drag is 30°. It's the seal which pulls the piston back and with the extra 15°. The rebuilt 1980 Camaro calipers I had were low drag and I just installed the 1977 Camaro calipers to make sure I do not have a low drag caliper.
https://www.google.com/url?sa=t&rct..._lowdrag.pdf&usg=AOvVaw3VAAKR0RwUk8oiFdEkajdo
I would agree with that link, but its not what I have noticed when dealing with 1978-2003 d154 metric calipers.
When it says it started in 1980, they were talking about the newly introduced GM front wheel drive platforms. I don't think the metric calipers received the the beveled grove in the caliper bore. I think they just received a beveled when they introduced the low drag caliper metric D154 in 1982, but truthfully I can't verify that they did the extra machine work to the caliper housing's bore.
As of today, all part numbers for the metric calipers are the same. A 1978 Monte Carlo caliper has the same part number as a 2001 S10 truck caliper.
As an example. A Raybestos front left caliper part number for a 2001 S10 is RAYBESTOS FRC4126, it is the same for a 1978 Monte Carlo. This is also the same part number for a 1982 F-body or a 1992 F-body. Same part number for a 1982 S-10 or a 2003 S10. 1978-1981 "G-bodies" use strait bore master cylinders. 1982-1988 G-bodies used step bore master cylinders. But all use the same caliper part number now. They do make new calipers now for the G-Body. These are the same part numbers for 1978-2003. I can only assume they are also NON low drag (normal) calipers because they are listed for all years.
ACDELCO 18FR625N Right
ACDELCO 18FR626N Left
RAYBESTOS FRC4126N Left
RAYBESTOS FRC4125N Right
The second gen F-body is different as they have three different part numbers. Left caliper is RAYBESTOS FRC4124 for 1978-81. 1977 seem to have a different part number for the left caliper RAYBESTOS FRC4220. 1970-76 had a different part number also RAYBESTOS FRC4060. You may be correct on low drag calipers in 1980 when they were build, but why would they have the same part number for 1977 when the stock master cylinder is not designed to work with a LOW drag caliper? It is still probably safe to go with the 1977 calipers for any F-body from 1977-1981. 1977 was also the first year of the redesigned B-body. They also used the same caliper caliper for 1977, but then changed to the 1978-1981 F-body caliper FRC4124 from 1978-1996 (for the 11" brake options).
I would agree with that link, but its not what I have noticed when dealing with 1978-2003 d154 metric calipers.
When it says it started in 1980, they were talking about the newly introduced GM front wheel drive platforms. I don't think the metric calipers received the the beveled grove in the caliper bore. I think they just received a beveled when they introduced the low drag caliper metric D154 in 1982, but truthfully I can't verify that they did the extra machine work to the caliper housing's bore.
As of today, all part numbers for the metric calipers are the same. A 1978 Monte Carlo caliper has the same part number as a 2001 S10 truck caliper.
As an example. A Raybestos front left caliper part number for a 2001 S10 is RAYBESTOS FRC4126, it is the same for a 1978 Monte Carlo. This is also the same part number for a 1982 F-body or a 1992 F-body. Same part number for a 1982 S-10 or a 2003 S10. 1978-1981 "G-bodies" use strait bore master cylinders. 1982-1988 G-bodies used step bore master cylinders. But all use the same caliper part number now. They do make new calipers now for the G-Body. These are the same part numbers for 1978-2003. I can only assume they are also NON low drag (normal) calipers because they are listed for all years.
ACDELCO 18FR625N Right
ACDELCO 18FR626N Left
RAYBESTOS FRC4126N Left
RAYBESTOS FRC4125N Right
The second gen F-body is different as they have three different part numbers. Left caliper is RAYBESTOS FRC4124 for 1978-81. 1977 seem to have a different part number for the left caliper RAYBESTOS FRC4220. 1970-76 had a different part number also RAYBESTOS FRC4060. You may be correct on low drag calipers in 1980 when they were build, but why would they have the same part number for 1977 when the stock master cylinder is not designed to work with a LOW drag caliper? It is still probably safe to go with the 1977 calipers for any F-body from 1977-1981. 1977 was also the first year of the redesigned B-body. They also used the same caliper caliper for 1977, but then changed to the 1978-1981 F-body caliper FRC4124 from 1978-1996 (for the 11" brake options).
I ordered 78 calipers and they was metric and confirmed by the rebuilder that they are low drag calipers, the number on the casting 18007150 / 18007151
www.speedwaymotors.com
1978-88 GM Metric G-Body Brake Calipers, IMCA Approved, 7/16-20
Uses common 7/16-20 SAE thread fluid inlet for larger brake hose compatibility Caliper features low-drag piston seal and piston dust seal for long life/street use Available as left or right side casting, only buy what you need for service/repairs Uses commonly found FMSI D154 reference number...
www.speedwaymotors.com
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Has anyone used the Wilwood or Speedway metric calipers with the 2.75" pistons with the stock sized rotors?
I just came across the Caliper I ordered for a 78 Seville which was advertised to have an SAE bleeder and Banjo but turned out to be metric. GM changed the banjo bolt from 7/16" x 20 in 77 to 10 x 1.5 in 78. I think they did that to prevent a conventional caliper from being installed on a 78 and up vehicle which has low drag calipers.
1978 - 1981 Camaro Front Disc Brake LH Single Piston Caliper
New 1978 - 1981 Camaro Front LH Disc Brake Caliper for all models. Great replacement Caliper at a great price! This 78, 79, 80, 91, and 81 single piston brake caliper is remanufactured to meet or exceed OEM
www.camarocentral.com
I ordered 78 calipers and they was metric and confirmed by the rebuilder that they are low drag calipers, the number on the casting 18007150 / 18007151
1978-88 GM Metric G-Body Brake Calipers, IMCA Approved, 7/16-20
Uses common 7/16-20 SAE thread fluid inlet for larger brake hose compatibility Caliper features low-drag piston seal and piston dust seal for long life/street use Available as left or right side casting, only buy what you need for service/repairs Uses commonly found FMSI D154 reference number...
From my experience, when the rebuilder is speaking of a LOW drag caliper, they are speaking about a LOW drag seal. There is a difference between the two terms. The LOW drag seal will work with any master cylinder as it is a square faced seal. LOW drag to them is a marketing term. "Is your caliper a LOW drag caliper on NON low drag?" Of course they are going to say LOW drag as no one wants a HIGH drag caliper (whatever that is). I don't really think they know what an original LOW drag caliper is or what it was designed to do.
From my experience, any rebuilt or new metric caliper is rebuild to NON low drag standards and will work with any master cylinder.
Extra money spent on an aftermarket type metric caliper, in my opinion, is a waste of money. I would only consider spending money on new calipers over rebuilt calipers. For the stock brake system, the bang for the buck is aftermarket pads, fluid flush, new rubber lines or stainless steel braided, and a right hand drive 2000 S10 master cylinder.
I would never neva neva neva ever buy a 1982-1997 rebuilt or new step bore master cylinder as a replacement master cylinder. I would go with the right hand drive S10 master cylinder and new or rebuild new calipers with an aftermarket pads. Since most cars are 30 to 40 years old, the rubber lines should be replaced as rubber will brake down over time and start to balloon. New rubber lines are fine but a stainless steel braided line will last much longer.
I'm not here to argue, I am just referencing what I have gone through to get a conventional caliper. Anyone can do what they want but what I did was to get a caliper where I did not have to hope or assume it is a conventional caliper and not a low drag. I was not prepared to order a metric calipers that I would have to remove the piston to make sure it is not a low drag caliper. When you order a metric 78 caliper you have no idea what you are getting. What I have now is a set up where I can order a 77 and down B52 caliper which was used on tons of cars and I know I'll never end up with a low drag caliper. The extra expense I paid to do it is the new flex lines and flex hose bracket modification. That being said, I don't know what options I would have if I was still using the stock G body caliper
I do appreciate on your site for manual brakes you note that low drag calipers cannot be used with a straight bore master. I didn't have to try to figure out why one pump of the pedal resulted in good brakes with the second application.
I do appreciate on your site for manual brakes you note that low drag calipers cannot be used with a straight bore master. I didn't have to try to figure out why one pump of the pedal resulted in good brakes with the second application.
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