1937-1957 Buick Oldsmobile Pontiac suspension upgrade
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==Brakes== | ==Brakes== | ||
[[image:41 frame bump good pic.jpeg]] | [[image:41 frame bump good pic.jpeg]] | ||
| − | The brakes on these cars definitely need improvement. That is not only the worst part of these cars, it is the first decision that dictates the path you follow in later steps. | + | |
| − | [The information listed here is general in nature and varies from model to model and year to year.] I’m diverting to a brake discussion here, because a decision on brakes determines the spindles you need, and you must have your spindles before you can design your suspension. | + | The brakes on these cars definitely need improvement. That is not only the worst part of these cars, it is the first decision that dictates the path you follow in later steps. [The information listed here is general in nature and varies from model to model and year to year.] I’m diverting to a brake discussion here, because a decision on brakes determines the spindles you need, and you must have your spindles before you can design your suspension. |
Earliest models had 1 ¾ by 11 inch brakes with 1 inch wheel cylinders. | Earliest models had 1 ¾ by 11 inch brakes with 1 inch wheel cylinders. | ||
Post war they were 2 ¼ by 12 with 1 1/8 wheel cylinders. The most basic upgrade would be to the later, larger, components. Control arms and spindles are unchanged for 20 years, so this is a basic bolt on. Even the shop manuals refer to this upgrade. | Post war they were 2 ¼ by 12 with 1 1/8 wheel cylinders. The most basic upgrade would be to the later, larger, components. Control arms and spindles are unchanged for 20 years, so this is a basic bolt on. Even the shop manuals refer to this upgrade. | ||
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My opinion is: close enough. The brakes are a vast improvement over manual drums, but not perfect. Stopping power is great to about the last 20% of pedal travel. I made several panic stops to test the system. At the very bottom, you just can’t push hard enough to lock them up. Simply put, the system needs a 9 or 10 inch booster to be perfect. The tech man I spoke with at CPP felt the 7 inch dual diaphragm would have been better, but not much. There simply isn’t enough power in a 7in booster to lock up a set of 215x75 15s on a 3500 pound car, on dry pavement. The reason I say close enough; this would only be an issue in a total panic situation, to a full stop, on dry pavement. In that situation, do you want them to lock up? | My opinion is: close enough. The brakes are a vast improvement over manual drums, but not perfect. Stopping power is great to about the last 20% of pedal travel. I made several panic stops to test the system. At the very bottom, you just can’t push hard enough to lock them up. Simply put, the system needs a 9 or 10 inch booster to be perfect. The tech man I spoke with at CPP felt the 7 inch dual diaphragm would have been better, but not much. There simply isn’t enough power in a 7in booster to lock up a set of 215x75 15s on a 3500 pound car, on dry pavement. The reason I say close enough; this would only be an issue in a total panic situation, to a full stop, on dry pavement. In that situation, do you want them to lock up? | ||
| − | Front Suspension | + | ==Front Suspension== |
Here is where the fun starts. The original idea came from a magazine article that showed an upgrade for a 55 Pontiac. Reading this article, which has some decent pictures, will get you thinking in the right direction. | Here is where the fun starts. The original idea came from a magazine article that showed an upgrade for a 55 Pontiac. Reading this article, which has some decent pictures, will get you thinking in the right direction. | ||
http://www.pontiacsafari.com/L1Garage/BallJointConversion.pdf | http://www.pontiacsafari.com/L1Garage/BallJointConversion.pdf | ||
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Note - later I added a power rack and pinion, and changed out the steering arms, but the pontiac arms will work fine on a 605 power box upgrade. | Note - later I added a power rack and pinion, and changed out the steering arms, but the pontiac arms will work fine on a 605 power box upgrade. | ||
| − | Springs | + | ==Springs== |
| + | The stock springs should work fine. As the Article suggested, you will need to spread the bottom of the spring a bit. The 58 Pontiac spring pocket is about ¼ inch larger than the previous years. I had chopped 3 inches out of my original springs to get ride height. So now I needed new springs. My original springs were too long, and to stiff, since the SBC conversion, so buying new stock ones made no sense. I went hunting replacements. FWIW, I needed a spring rate of approximately 300 pounds, with a ride height of 9.5 inches and a free height of 15 inches. I ended up with 69 Cougar springs. They were listed at 295 pounds, 10.5 ride height and 17 inches free height. Once I cut a full coil off, everything fell into place. They were also 3.88 inches in diameter. Halfway between the original upper pocket and the 58 lower pocket. | ||
| − | Shocks | + | ===Shocks=== |
| + | Shocks will be a problem on the pre 50’s, without a shock tower. Note on the picture of the frame spring pocket area. 3 Holes in a row. The outer 2 are the original mounting holes for the lever action shock. The one in the middle is drilled at the dead center of the spring pocket, later enlarged to fit the shock bushing. | ||
[[image:Mocked_mount_top_view.jpg]] | [[image:Mocked_mount_top_view.jpg]] | ||
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