I’m hoping that someone who has solid knowledge about the front suspension on a 1941 Ford can help me get the best ride out of my 2 door sedan. Stock axle, Posies super slide spring with recommended shackles (supposed to provide a 3”drop over stock) and tube shocks. I have bias ply tires and the car has been professionally aligned. The shackles are completely vertical with the car sitting on a flat surface. When I realized this I thought for sure I had the wrong spring since ‘41s are known to have some “unique” parts. There is a spring available that seems like it would fit and provide the accepted 45*(\/) angle. This is where it becomes murky. After doing much research about what the correct spring length should be, I have seen information that in 1941 Ford changed the front to cause the shackle angle to be vertical. I’m trying to get the most out of the front end because if I hit a pot hole, it is not forgiving. I’m not sure if I am looking for something that is not realistic or if something will improve what I have.
I'm thinking that those straight down get the car a bit lower shackles are letting it swing to the side when you did hit one of those potholes that you were supposed to miss. The 45 or close to it degrees angle on the shackles lets the spring compress or rebound but the axle stays centered rather than wanting to move to one side. The first step is to get under it with the weight on the tires and decide if you have room between the spring and the hanger to run shorter shackles that angle in some but I am thinking that the spring is too long for that car.
Does Posies have a special spring for 41’s? Im not a 41 expert. Do they have a panhard bar on the front like a 48 does? If they do, then the vertical shackles are just fine. If they don’t, your shackles should be at a 45 degree angle like 48Chev said.
If you're looking for driveability to go along with a good ride, consider losing the bias ply tires (blasphemy). Didn't the change to vertical shackles occur at the same time they adopted the anti-sway bar? (It was some time in there.)
I realize that the bias plies are not helping the situation but for the time being, they are going to stay because they are really right for the rest of the build (mild custom ‘48-‘52). The car has an anti-roll bar that is pretty scrawny, not sure how effective it is but that’s what is there from the factory. If having the shackles being vertical is the reason for the harsh ride, I would consider changing to shorter shackles or getting the main leaf narrowed by a local spring shop. Is the spring basically not able to perform properly because of the shackle angle (even though I think this is how the factory designed it)?
The anti roll bar on a 41 actually does some double duty. the way it’s mounted it serves as a rudimentary anti sway bar also Between the ridge on the anti roll bar where the bushings are and the knuckle on the outer ends It does a fairy good job of locating the axle side for side If your front bone is unsplit that helps also I had longer shackles in the front of the chopped 41 coupe I built and I had no problem with bias ply tires
41 Fords had a panhard bar and sway bar. If the sway bar and panhard bar have good bushings and rest of the joints [tie rod ends/shocks] are good then the vertical shackles are not an issue. I have read on this forum that a M11 suspension is no better in ride department from person(s) that have had both . However the tires [radial] are what would make it the best it can be.
I thought by “not forgiving” you meant it had bump steer or death wobble. Never figured you just meant it was a harsh ride. If the thing rides too rough, you might want to replace the front rubber axle bumpers with some fresh 48 Ford rear bumpers. They will give more cushion to the compression. And if there is a panhard bar in the front, the vertical shackles should actually give you a softer ride than the 45 degree ones. But you need the panhard to keep it from swaying sideways on turns and big bumps.
In addition to the bias ply tires, which may not be perfectly round, what are the front shocks? Hopefully not the typical hot rod shock
What pressure are you running your tires at? My 40 Ford is at 28 psi up front on 640-15s and 20psi in the rear on 820-15 Firestones . It drives perfectly, also has a posi spring and tube shocks.
May or may not be relevant, but how old are the tires? I have an as new Firestone lying around on which the rubber feels almost petrified. Other Firestones I have feel kinda rubbery, as you'd expect. Chris
Make sure your shocks aren't bottoming out. That suspension should ride quite well. The Posie spring might be a little too stiff for your car. If the ride height is good, you can't remove any spring leafs to soften it. The vertical shackles don't affect the ride at all. The ones on my avatar are vertical. You should have a panard rod on the front end though with the vertical shackles.
Thanks for all the responses so far. The car was completed 4 years ago and the tires were old but pliable with 0 miles on them. The shocks are regular Monroe units and as I remember had about 4" compression from midpoint. Since this is a seasonal car and it's sleeping now, I may not be diving right into big changes, but this definitely gives good info about areas to look a bit closer. Maybe remove one leaf from the spring. The tire pressure is definitely on the change list. This is the car in question, overall I'm really happy with it but would like to improve this one area (maybe I should just stop hitting potholes, almost impossible around here).
I may have missed it but are the shocks straight up and down. On my forty one I drove around with no shocks at all and it rode good and soft. I installed the gas shocks with the brackets that were on the frame and they mounted them straight-up-and-down, which made a hard ride.
"" (maybe I should just stop hitting potholes, almost impossible around here)."" I can relate to that being here in CT!
I can't imagine that having the spring shackles vertical is correct. Definitely seems like that would lead to problems, especially when the shackle "over-centers" during a one-wheel event (like a pot-hole). Can you post a picture of the current setup?
Here is the angle of the shackle on my 41. It's got the panhard bar and sway bar. A few leaves removed, so it's even more than vertical.
OK, first off you and I are using the same language a bit differently, but that is why pictures are worth a 1000 words. To me, that shackle is angled outboard enough from the vertical position that it should not be a problem when compressing the suspension from ride height (in the image) to full compression. However, I would be concerned if there is a enough suspension travel so the shackle passes through the vertical position under rebound, and is perhaps even angled slightly inboard at full extension. You would have to lift the car up and let the suspension droop to find out. This is where you could run into a problem as it would essentially cause the shackle to bind when travelling through the vertical position.
does a 41 ford share the 40 axle? if so they are 38.5 on the perch 42 up is 41 inches perch to perch so for arguments sake the difference total is 2.5 inches 1 1/4 each side so IF that axle pictured is a 40 and it has a 42 up spring in it, will it look like that? if you have a 38.5'' 40 axle with a stock 37-40 bone, the spring wants to be 39.5'' laden it does look like that is what has happened, easy to measure the perches to determine if its 40/41 or 42/47
or if that car is 'supposed' to have a 42-47 front axle king pin to king pin 50.5 i think and it has had a 40 axle fitted to it - -to narrow the track one inch each side that may well be the ache, as it has its stock spring BUT it has non stock tie rod
erm it may well be the reason IF those lower shock mounts are stock, that the shock looks too perpletickler, as its lower mounting is 1.14/4 inches inboard non stock
I was able to get a couple of photos. The spring is 39", the shocks are vertical and there is a sway bar, no panhard. I believe the axle is the same 37-41. Pretty sure this is how it came from the factory except for the tube shocks and lowered slider spring.
When I installed the Posies spring I removed this spacer that was between the original spring and the crossmember. If I re-install it on top of the Posies spring, how will it affect the rest of the components (shackles, etc.)
do you have a split wishbone does it appear that in order to get the eye in the correct plane its been bent at the perch pin and not at the spring hanger eye
My 41s (3) ride softer than my wifes new Lincoln Aviator. No kidding. 2 have the original shocks (rebuilt) the coupe has tube shocks . No reverse springs , rebuilt front suspension on all . The coupe , with the tube shocks,had a problem at first . Bottoming out on speed bumps if at speed . Longer shocks and mounting solved the problem. The Pete And Jakes shocks , supposedly made for the 41 , along with there mounts weren’t designed for the suspension travel the car has .
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