Metric oversized calipers.

[buzz77]

I know about all the brake upgrades. But since I want to keep my 79 GP as a simple cruiser, if these US brake calipers with the larger 2.75 piston actually enhance stopping power. I cant seem to find a definate consensus on how well they work.

Also for all the guys that have fairly stock g-body brake systems, what is the best improvement where you noticed the improvement? Braided hoses? Slotted rotors? Brake pads? If so, which ones.

 

[Fox80]

I can tell you from circle track experience that oversized calipers make a HUGE difference in stopping power. If you look up my newbie 442 in the new users section there is pics of the pro stock car I ran, we were required by rules to run a "metric" caliper on all four corners and you had to use larger calipers and high temp pads to stop a 700hp 3,000 pound car. But I would not use US brake parts they suck, Southwest speed offers the best ones hands down that I've ever used, the braided hoses would help with the firmness of the pedal. Slotted rotors on a street only car are for looks only, you will never get the pads hot enough to have to worry about venting the gas from under the pad. If your car still has drums on the back that would be the first upgrade I would worry about is a rear disc conversion. But in all reality the tire will lock up on these cars before you even tax a well maintained stock brake setup. When I redid all the brakes on the Cutlass I used all AC Delco stock type parts ie calipers,rotors,pads,drums,shoes,wheel cylinders,and master cylinder and it stops better than most new cars I drive.

 

[buzz77]

Thanks fox

I noticed on the speedway calipers that you can either choose the stock 2 1/2 or a larger 2 5/8 piston. Hard to believe a 1/8th increase in piston size can do much. But 80 bucks for the pair maybe worth a try.

Also any idea what the difference is between cast iron and cast steel? The speedway are cast steel.

 

[Fox80]

All of the calipers are just larger bore stock style calipers, I don't think there is more than one kind of steel used its just different ways of saying it. And a1/8" does make a difference get yourself a brake pressure gauge that threads into the bleeder and you will be amazed. Stock style calipers with dual racing master cylinders would give us around 500psi (not enough) of brake pressure, oversized calipers with the same master cylinder and a -3an braided line would take that to over 700psi at all four corners. Now granted this is more than double the pressure that any vacuum assisted street car makes the theory is still the same. Just remember the smaller the bore on the master cylinder and the smaller the line equals more pressure, the larger the caliper bore the more pad clamping pressure it can produce plain and simple. Just make sure for the safety of you and your neighbors if you put braided lines on any street car they are DOT approved they are made a lot better than a racing line.

 

[buzz77]

Thanks. I'm still on the fence on whether I should get them or stick with stock. But after searching on speedway, I'm actually surprised they sell a 2.75 caliper for our cars with all the hardware and pins and brake pads for only 60 bucks per side. I dont think many people are aware of this great price. Perhaps we rely on summitracing too much.

 

[Fox80]

The pads in that setup are junk they won't last. In my experience most of speedways stuff is just cheap junk. You can do what you want but if you want a upgrade go with the southwest calipers and a good quality pad, preferably ceramic ie Raybestos, AC Delco, or EBC

 

[pontiacgp]

I get my rebuilt calipers from Napa that come with all the hardware for around $20 and use EBC pads and the only thing I have to worry about is if the car behind me can stop as fast as I can. Make sure your rear brakes are in great condition as well. One problem with the rear brakes on a G body is the cylinder moves around. The A body rear I have has bolt in cylinders and that improved the rear braking

 

[buzz77]

Thanks guys,
Yeah, since this wont be a race car with a 301, I'll leave the calipers stock, get a good ceramic pad. The lines are rusted so ill be replacing them with pre bent lines from inline tube and some dot approved braided hoses.

Napa sells reman calipers with hardware for only 20 bucks or so? I may get those just to paint and replace the rusty ones.

 

[Fox80]

Yea he makes a good point I forgot about the clip in wheel cylinder, I got the AC Delco loaded calipers (caliper,pads,and hardware) from rock auto for pretty cheap

 

[clean8485]

If you go with a caliper with a larger diameter piston, does this have any effect on how the clip that goes on the back of the inboard brake pad fits? I don't know if you call it an "anti rattle" clip, or a "retainer" clip, but it helps to hold the inboard brake pad into the piston in the brake caliper.