1937-1957 Buick Oldsmobile Pontiac suspension upgrade
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The upper control arm mount is a fairly simple fabrication. If you have a pre 50’s car, the upper mount will differ from the article. The pre 50’s had the lever action shock, therefore no upper shock mount. On both of our conversions (41 Pontiac and 49 Olds) we fabricated the mounts out of angle iron. We used ¼ in. 3x3 angle iron on the Pontiac and added 2 gussets. On the Olds we had some 3/8 in. 4x6 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 * is fine, as long as the upper ball joint is not in a bind. | The upper control arm mount is a fairly simple fabrication. If you have a pre 50’s car, the upper mount will differ from the article. The pre 50’s had the lever action shock, therefore no upper shock mount. On both of our conversions (41 Pontiac and 49 Olds) we fabricated the mounts out of angle iron. We used ¼ in. 3x3 angle iron on the Pontiac and added 2 gussets. On the Olds we had some 3/8 in. 4x6 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 * 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, my spindle center was 12.5 inches off the ground. I blocked the frame, so that when the lower A was level, the spindle was 12.5 in up) Even a small error here will be costly. It takes ½ inch of shims to adjust 1 degree of camber. If you need to put additional shims on therear 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 finished, basically driveable. So get this part right. If you have any doubts, shade towards the positive camber side, you can add more shims later to move it towards negative. Likewise, move the upper mount to a position about 3/4 inch behind the plumb line for the spindle, to set up at least 5 * of caster in the neutral position (neutral being the static position as mocked up, before final alignment). If you intend to add power steering, I would shoot for 6 * in the neutral position, but don’t get the uppers so far behind the lowers you put the ball joints in a bind. I drilled holes in the bottom plate of the angle iron and when I had it mocked up, I drilled thru the frame and bolted it up with 3/8 inch bolts. This was strong enough to allow me to assemble the entire front end, with springs, put the wheels and tires on it and set it on the ground. Since I had my engine in, I was basically in a final drive setup. I double checked everything, then tore it down and had it welded in place. | Be sure the frame is level side to side and has the correct front to rear angle that you want. (with 15 inch wheels, my spindle center was 12.5 inches off the ground. I blocked the frame, so that when the lower A was level, the spindle was 12.5 in up) Even a small error here will be costly. It takes ½ inch of shims to adjust 1 degree of camber. If you need to put additional shims on therear 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 finished, basically driveable. So get this part right. If you have any doubts, shade towards the positive camber side, you can add more shims later to move it towards negative. Likewise, move the upper mount to a position about 3/4 inch behind the plumb line for the spindle, to set up at least 5 * of caster in the neutral position (neutral being the static position as mocked up, before final alignment). If you intend to add power steering, I would shoot for 6 * in the neutral position, but don’t get the uppers so far behind the lowers you put the ball joints in a bind. I drilled holes in the bottom plate of the angle iron and when I had it mocked up, I drilled thru the frame and bolted it up with 3/8 inch bolts. This was strong enough to allow me to assemble the entire front end, with springs, put the wheels and tires on it and set it on the ground. Since I had my engine in, I was basically in a final drive setup. I double checked everything, then tore it down and had it welded in place. | ||
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| + | For spindles, I started with the 63 Pontiac spindles as advised in the article. ( Tapered bearings and a good Scarebird kit available.) Unfortunately when I set it on the ground, it was too high. This led to a search for dropped spindles. BOP – they don’t exist. | ||
| + | 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* bend at the bottom. That is to clear the wide corners on the lower control arm. The 60’s stock Chevy spindle has a 45* angle there, and won’t work. The third spindle is the 65-70 Chevy drop spindle from CPP (Classic Performance Products). It is their own in house design and is very close to the dimensions/configuration of a Pontiac spindle. I had to trim the ears off the front side of the lower A frame, but that was a minor modification. | ||
| + | Here is where I appreciated the bolt in mock up. The dropped spindle from CPP was almost 2 inches longer than the stock spindle. Not a problem, in fact they say the longer spindle gives move stability. But the longer spindle changed the geometry and I had to reset the location of the upper control arm mounts. Glad it wasn’t welded in at this point. | ||
| + | Note: CPP’s drop spindle is available alone, or in a disc brake kit. Be sure you get the 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, even the taper is the right direction. Unlike the 63 Pontiac arm in the article, the Chevy arms are pretty straight. I only needed to shorten my tie rods less than an inch, rather than the 3 inches in the article. I got there by trimming a little off both the inner and outer tie rod threads and the sleeve. No cutting and welding. | ||
| + | Incidently, It looks like my tie rod ends 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 I had to ream them a touch. | ||
| + | The CPP drop spindle/disc brake kit uses Chevelle 11 inch rotors and S10 Calipers. | ||
| + | When I priced the individual pieces, it was cheaper to order the entire kit, plus it was a matched set. Spindles, Rotors/hubs, bearings, brackets, calipers, pads, flex hoses, Nuts, Washers, even cotter pins, $500. Service was unbelievable, 3 days from phone call to parts in hand. | ||
| + | So there is your most straight forward approach. 58 Pontiac Upper and lower Control arms and either 63 Pontiac spindles and Scarebird brackets for disc brakes and stock height, or CPP Dropped spindles and their setup. | ||
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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. | ||
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| + | 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. | ||
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| + | 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. I used a pair of shocks from a 79 Dodge Diplomat. They have the Stem mount on both ends. Easy to mount through that frame hole. I had to fabricate the lower mount. (Even tho the lower Control arms had shock mounts, there were no shocks short enough that fit that mount). With level control arms the ride height on my car was 9.5 inches. That meant a shock collapsed height of about 7 1/2 inches. The Dodge shocks were not only the right ride height, they were designed for a similar weight car. | ||
| + | Note: 58 Buick has an external shock mount, riveted to the frame. You could get a set of those, or fabricate some, and have many more shock options than you would up the center of the spring. | ||
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| + | For the more adventuresome, and fabrication minded, there is another approach. | ||
| + | The only real issue with the stock lower control arms is the king pin mounts. My buddy with the 49 Olds has a yard, but no 58 Pontiacs. He didn’t want to wait for one to come in, so we cut the outer end off his lower control arms and welded on a 3/8 plate for a ball joint mount. He did have a 58 Buick, so those were the uppers we used. He had already pulled a complete spindle/disc brake setup off an early 70’s Chevy so we knew going in the 45* angle on the spindle was going to be a problem. As it turns out, the narrower end on the original lower control arms is a blessing. A chevy spindle can be made to work, but he knew the Ford Courier had a ball joint with a 3 point “crowsfoot” design. It is very narrow at the outer end, and the Chevy spindle cleared with no problems. There must be several ball joint mounts that could be adapted to the original arms. Just remember, the ball joints point down. | ||
| + | We used his original springs, but don’t have it finished yet, so we may do some adjusting to the ride height when all is said and done. Be aware, if you use a disc brake kit with the caliper to the front, you will probably have an issue with the sway bar. | ||
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| + | One other tidbit. The 40’s cars had very small sway bars. 5/8th inch. Happened to stumble across a 56 Buick. The sway bar was ¾ inch and bolted in without modification. | ||
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| + | Well, there it is. Hopefully enough information to convince you to upgrade, not sub frame. Sorry I didn’t take more pictures. Oh yeah, forgot to say, it works great. | ||
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| + | The next step will be a steering upgrade. Not that you have to have it, but there have been some improvements in the last 65 years. I’m also keen on putting in a tilt steering column with turn signals, so the time is ripe. On my buddy’s 49 Olds a 605 power steering box bolted in like the original. I can’t make it fit my 41, so I’m chasing a rack and pinion setup. | ||
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| + | Thanks to Chieftain, Grouch, John, Scarebird, CPP, California Pontiac and a few others for putting up with me while I sorted this out. | ||
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| + | Feel free to PM me if I’ve left you more confused than enlightened. | ||
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