1937-1957 Buick Oldsmobile Pontiac suspension upgrade

The next section will deal with the brakes.  That is not only the worst part of these cars, it is the first decision that  

The next section will deal with the brakes.  That is not only the worst part of these cars, it is the first decision that  

dictates the path you follow in later steps.

dictates the path you follow in later steps.

[[image:41 frame bump good pic.jpeg]]

[[image:41 frame bump good pic.jpeg]]

The brakes on these cars definitely need improvement.  

The brakes on these cars definitely need improvement.  

[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 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.  

  Also we do not have a 58 Olds to check those lower control arms. What we do know is 57 is king pins, and 59 is all new.  So 58 is it.  We used the 58 Pontiac upper control arms simply because we got the whole front end. Make a note that several uppers will work. Looks like 58 to 60 BOP’s all had the same basic dimensions on their upper control arms.  In fact, the 58 Buick uppers we used on one conversion had some built in twist that allowed us to add more anti dive than we could get with the Pontiac uppers.  

  Also we do not have a 58 Olds to check those lower control arms. What we do know is 57 is king pins, and 59 is all new.  So 58 is it.  We used the 58 Pontiac upper control arms simply because we got the whole front end. Make a note that several uppers will work. Looks like 58 to 60 BOP’s all had the same basic dimensions on their upper control arms.  In fact, the 58 Buick uppers we used on one conversion had some built in twist that allowed us to add more anti dive than we could get with the Pontiac uppers.  

As you can see in the pics, the 58 control arms are more substantial than the 41.  But all dimensions are the same.

As you can see in the pics, the 58 control arms are more substantial than the 41.  But all dimensions are the same.

[[image:58 pontiac 41 pontiac lower control arm s.jpg]]

[[image:58 pontiac 41 pontiac lower control arm s.jpg]]

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.

[[image:Upper mount mocked up side view.jpeg]]

[[image:Upper mount mocked up side view.jpeg]]

[[image:Uper mount mocked 2.jpeg]]

[[image:Uper mount mocked 2.jpeg]]

[[image:Mocked mount top view.jpeg]]

[[image:Mocked mount top view.jpeg]]

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.  

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.   

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.   

[[image:Cpp - Pont - chevy spindles.jpeg]]

[[image:Cpp - Pont - chevy spindles.jpeg]]

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.  

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.