1937-1957 Buick Oldsmobile Pontiac suspension upgrade
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But if your car is assembled with the engine in and fenders on, or your fabrication skills are minimal, or you just don't like the idea of hacking your frame, the information in this article may be useful to you. | But if your car is assembled with the engine in and fenders on, or your fabrication skills are minimal, or you just don't like the idea of hacking your frame, the information in this article may be useful to you. | ||
| − | [[image:41 frame bump good pic.jpeg| | + | [[image:41 frame bump good pic.jpeg|thumb|left|400px|Built in spring pocket on the frame]] <br style="clear:both"/> |
==Brakes== | ==Brakes== | ||
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As you can see in the photos, the '58 control arms are more substantial than the '41. However, all the dimensions are the same. | As you can see in the photos, the '58 control arms are more substantial than the '41. However, all the dimensions are the same. | ||
| − | [[image:58 pontiac 41 pontiac lower control arm s.jpg| | + | [[image:58 pontiac 41 pontiac lower control arm s.jpg|thumb|left|400px|The '58 Pontiac control arms are more substantial than the '41s, but dimensions are the same.]] <br style="clear:both"/> |
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| − | + | The upper control arm mount is a fairly simple fabrication. If you have a post '50s car, the upper mount will differ from this article. The pre-‘50s had the lever action shock, therefore no upper shock mount. On both of our tested conversions ('41 Pontiac and '49 Olds) we fabricated the mounts out of angle iron. We used 1/4" 3x3 inch angle iron on the Pontiac, and added two gussets. On the Olds, we had some 3/8" 4x6 inch angle iron, so only added one gusset. | |
| − | Note in the pictures how the front mount is higher than the rear mount. This sets up the anti-dive angle. Up to 10 degrees is fine, as long as the upper ball joint is not in a bind. Be sure the frame is level side-to-side, and has the correct front-to-rear angle that you want. With 15 inch wheels, the spindle center was 12.5 inches off the ground. The frame was blocked, so that when the lower A-arm was level, the spindle was 12.5 inches up. | + | [[image:49_olds_upper_mount_1.jpg|thumb|left|400px|'49 Olds]] <br style="clear:both"/> |
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| + | Note in the pictures below how the front mount is higher than the rear mount. This sets up the anti-dive angle. Up to 10 degrees is fine, as long as the upper ball joint is not in a bind. Be sure the frame is level side-to-side, and has the correct front-to-rear angle that you want. With 15 inch wheels, the spindle center was 12.5 inches off the ground. The frame was blocked, so that when the lower A-arm was level, the spindle was 12.5 inches up. | ||
Even a small error here will be costly. It takes 1/2" of shims to adjust just 1 degree of camber. If you need to put additional shims on the rear of the bracket to increase caster, and can't take enough out of the front to keep the camber static, you will have to cut it loose and start over. Unfortunately, you can't do a full alignment until it is totally basically finished and drivable. So, get this part right. If you have any doubts, shade towards the ''positive'' camber side, as you can add more shims later to move it towards negative. Likewise, move the upper mount to a position about 3/4" behind the plumb line for the spindle, to set up at least 5 degrees of caster in the neutral position (neutral being the static position as mocked up, before final alignment). | Even a small error here will be costly. It takes 1/2" of shims to adjust just 1 degree of camber. If you need to put additional shims on the rear of the bracket to increase caster, and can't take enough out of the front to keep the camber static, you will have to cut it loose and start over. Unfortunately, you can't do a full alignment until it is totally basically finished and drivable. So, get this part right. If you have any doubts, shade towards the ''positive'' camber side, as you can add more shims later to move it towards negative. Likewise, move the upper mount to a position about 3/4" behind the plumb line for the spindle, to set up at least 5 degrees of caster in the neutral position (neutral being the static position as mocked up, before final alignment). | ||
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If you intend to add power steering, shoot for 6 degrees in the neutral position, but don't get the uppers so far behind the lowers that you put the ball joints in a bind. In this situation, holes were drilled in the bottom plate of the angle iron, and, when it was mocked up, the frame was drilled and bolted up with 3/8 inch bolts. This was strong enough to allow for assembly of the entire front end, with springs, putting the wheels and tires on it, and setting it on the ground. Everything was double-checked, then torn down and welded in place. | If you intend to add power steering, shoot for 6 degrees in the neutral position, but don't get the uppers so far behind the lowers that you put the ball joints in a bind. In this situation, holes were drilled in the bottom plate of the angle iron, and, when it was mocked up, the frame was drilled and bolted up with 3/8 inch bolts. This was strong enough to allow for assembly of the entire front end, with springs, putting the wheels and tires on it, and setting it on the ground. Everything was double-checked, then torn down and welded in place. | ||
| − | [[image:Upper_mount_mocked_up_side_view.jpg| | + | {| |
| − | [[image:Uper_mount_mocked_2.jpg| | + | |[[image:Upper_mount_mocked_up_side_view.jpg|thumb|center|400px|Upper control arm mount, mocked up]] |
| + | |[[image:Uper_mount_mocked_2.jpg|thumb|center|400px|Upper control arm mount bolted in for mock up]] | ||
| + | |} | ||
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| − | + | For spindles, the '63 Pontiac spindles advised in the article were used. Unfortunately, when it was set it on the ground, the front ride height was too high. This led to a search for dropped spindles. For BOP, dropped spindles couldn't be found. Chevy drop spindles are readily available, but they come with a problem. Note the side by side comparisons in the picture. The '63 Pontiac spindle has a deep 90 degree bend at the bottom, to clear the wide corners on the lower control arm. The ‘60s stock Chevy spindle has a 45 degree angle there, and won’t work. | |
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| − | The third spindle is the '65-'70 Chevy drop spindle from Classic Performance Products. It's their own in-house design and is very close to the design of a Pontiac spindle. The ears had to be trimmed off the front side of the lower A frame, but that was a minor modification. | + | {| |
| + | |[[image:63_pontiac_65_chevy_spindle_2.jpg|thumb|center|400px|Pontiac (bottom) vs. Chevy spindle shape]] | ||
| + | |[[image:Cpp_-_Pont_-_chevy_spindles.jpg|thumb|center|400px|CPP custom spindle/Pontiac/Chevy]] | ||
| + | |} | ||
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| + | The third spindle shown below is the '65-'70 Chevy drop spindle from Classic Performance Products. It's their own in-house design and is very close to the design of a Pontiac spindle. The ears had to be trimmed off the front side of the lower A-frame, but that was a minor modification. | ||
| − | [[image:IMGP0005.JPG| | + | [[image:IMGP0005.JPG|thumb|center|400px|Trimmed lower control arm]] <br style="clear:both"/> |
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| − | Here is where the bolt-in mock up | + | Here is where the bolt-in mock up really paid for itself in time and labor saved. The dropped spindle from Classic Performance Products (CPP) was almost 2 inches longer than the stock spindle. Not a problem, and in fact, they say that the longer spindle gives more stability. However, the longer spindle changed the geometry, and the location of the upper control arm mounts had to be replaced. Fortunately, it wasn't welded in at this point. |
| − | CPP's | + | CPP's dropped spindle is available alone, or in a disc brake kit. Be sure you get the p/n CP30101 spindle. It has no steering arms built in. |
| − | Stock spindles are front steer, and won’t work. With the CP30101, you can just add a pair of '65-'70 stock arms. Flipped over, they fit your rear steer perfectly | + | Stock spindles are front steer, and won’t work. With the CP30101, you can just add a pair of '65-'70 stock arms. Flipped over, they fit your rear steer perfectly-even the taper is the right direction. Unlike the ‘63 Pontiac arm in the article, the Chevy arms are pretty straight. |
For this project, the tie rods only needed to be shortened less than an inch, rather than the 3 inches in the article. This was done by trimming a little off both the inner and outer tie rod threads and the sleeve. No cutting and welding. | For this project, the tie rods only needed to be shortened less than an inch, rather than the 3 inches in the article. This was done by trimming a little off both the inner and outer tie rod threads and the sleeve. No cutting and welding. | ||
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Incidentally, It looks like the tie rod ends in this project are closer to the Ackerman line than the '55 conversion in the article. The taper in the Chevy arms was a bit small for the Pontiac tie rods, so they had to be reamed a touch. | Incidentally, It looks like the tie rod ends in this project are closer to the Ackerman line than the '55 conversion in the article. The taper in the Chevy arms was a bit small for the Pontiac tie rods, so they had to be reamed a touch. | ||
| − | The CPP drop spindle/disc brake kit uses Chevelle 11 inch rotors and Chevy S-10 calipers. In this case, it was cheaper to order the entire kit, | + | The CPP drop spindle/disc brake kit uses Chevelle 11 inch rotors and Chevy S-10 calipers. In this case, it was cheaper to order the entire kit, than getting the individual pieces. And with the kit, you get a matched set: spindles, rotors/hubs, bearings, brackets, calipers, pads, flex hoses, nuts, washers, and even cotter pins, all for about $500. |
| − | That's the most straightforward approach | + | That's the most straightforward approach: '58 Pontiac upper and lower control arms, and either '63 Pontiac spindles and Scarebird brackets for disc brakes and stock height, or Classic Performance Products dropped spindles and their set-up. |
| − | + | Note: Later a power rack and pinion was added, and the steering arms were changed out. However, the Pontiac arms will work fine on a Saginaw 605 power box upgrade. | |
==Springs== | ==Springs== | ||
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