1950 Custom Wheelbase offset? Spring rubbing

G

GearheadMn

Junior Member
I’m helping someone with a 1950 Custom. The left front coil spring rubs against the rear side of the hole in the frame. The right spring is centered in its hole. The wheelbase on the right measures 114” (correct), but the left side is 113 1/2. The tire is also noticeably closer to the fender on l/f.
There is no visible damage to the lower control arm or frame and the control arm appears to be correctly attached to the frame.
It’s been on a wheel alignment rack and the Thrust Angle is within specs. The wheel alignment isn’t completed yet but everything looks within the margins.
Many years ago I recall hearing something about offset wheelbase on some older cars but I’m not sure if it’s true. Given the coil spring rub I’m doubtful that this would be considered normal.
The only other factor I’ve considered is that these aren’t original springs; they may have a larger diameter than stock.
Thoughts?
 
I’ve never heard of “offset wheelbase” on a Shoebox era car……it sounds like the top of the spring isn’t seated correctly…..but that shouldn’t change the wheel base. I would take the front tire off on that and check real close for something bent or out of position where the control arms meet the frame. I’m not sure of what the “Thrust angle” is when talking about the alignment………Mark
 
Thanks Mark! Sadly the spring is seated correctly top and bottom, (I failed to mention that in original post).
A closer look with the wheel off is good idea.
Thrust angle is primarily a factor on newer cars that don’t have independent rear suspension but it can also be an indicator of a bent frame issue.
 
Sounds like badly repaired collision damage to me. Or maybe even unrepaired (out of sight, out of mind).
 
New springs installed? Ford had the top of the spring milled flat, if not, the spring will not fit correctly. When I purchased new springs from Eaton Detroit, they did not have the flat on the top of the spring.
Wheelbase dimension off .5"? Is there visible damage on the frame? How do the doors close, and fender gaps? Recheck the wheel base measurement. Also do a 'X' measurment from under the frame in the front; from two points and frame width from center to each side in the front. On the rack with a laser going down the center, measuments can be made.
Are you referencing camber - thrust angle? Camber is an issue on these for sure. Shoebox Central has a nice set up to add some camber, and make it much easier to adjust.
Some random thoughts over coffee this morning.
Gearhead, keep us informed, good luck.
 
WGA - thank you! I did the X measurements and it looks perfect so I decided that maybe I wasn’t dealing with a frame issue; it was the rubbing of the spring on the back side which continued to puzzle me.
Your description of the issue with springs not being flat on top intrigued me. My friend already had a new set of lowering springs sitting on the bench and they had the desired flat top. I used a small extendable mirror to look up inside the current springs and, sure enough, they weren’t flat!
So I decided to just ignore any possible frame issues for the moment and remove the springs. Darned if they hadn’t had a half coil or more cut off of them and the top was as crooked as all get out! So I felt pretty confident that installing the new springs would resolve the rubbing issue and, yep, it did! Such a relief and the car also has a nice rake to it.
Next a wheel alignment and she should be good to go. Thanks so much for the advice!
John
 

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GearheadMn said:
WGA - thank you! I did the X measurements and it looks perfect so I decided that maybe I wasn’t dealing with a frame issue; it was the rubbing of the spring on the back side which continued to puzzle me.
Your description of the issue with springs not being flat on top intrigued me. My friend already had a new set of lowering springs sitting on the bench and they had the desired flat top. I used a small extendable mirror to look up inside the current springs and, sure enough, they weren’t flat!
So I decided to just ignore any possible frame issues for the moment and remove the springs. Darned if they hadn’t had a half coil or more cut off of them and the top was as crooked as all get out! So I felt pretty confident that installing the new springs would resolve the rubbing issue and, yep, it did! Such a relief and the car also has a nice rake to it.
Next a wheel alignment and she should be good to go. Thanks so much for the advice!
John
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You say that "the car also has a nice rake to it.". Did you perchance use Aerostar springs?
 
Check both front wheels for the back spacing. Sounds like one wheel may have more back space to the inside.
 
My apologies for the delay in replying; long story. The springs I installed came from Shoebox Central, 2 inch drop part number 8A-5310-2IN.
Now realistically we can be pretty sure that Shoebox is not making these springs themselves and even likely that they’re not even commissioning them from someone. They very possibly are the Aerostar springs being produced by a high volume parts company and re-packaged, (they were in a plain brown cardboard box without even a part number on it).
But I’ll say this; they fit well and made for a nice front end drop.
 
A general update for anyone who happened to review this thread; following the front spring replacement the wheel alignment was completed and everything came out fine, (although the caster wasn’t able to be brought fully into spec because of the lowering).
But the camber and toe-in were fine and she goes down the road straight. Even after the alignment the wheelbase is still 1/2 shorter on left versus right but it doesn’t seem to matter.
Very interesting situation. Thank you everyone for your feedback!
 
Maybe locate a frame feature that is the same on both sides and measure from there forward and rearward to determine which end of the car is off.

I have seen bent axle housing, sheared center bolts, etc causing the back to be off.

Front differences on independent suspension cars have usually been due to suspension or frame damage. Since you have X measured the frame to be square and have worked with the components when changing springs, the back may be at fault.

Seems like 1/2" difference would effect something sometime, tire wear, uneven pull during emergency braking; or maybe not?
 
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