I am in the (ridiculously slow) process of building a Model A hot rod keeping a transverse leaf spring. I am installing a Ford 8” and I’m thinking of going to a “spring behind axle housing” like a V8 Ford uses. This would require that the rear crossmember would have to be farther back than on a stock Model A. Is there enough room to just add a 2nd crossmember and leave the original in place or is that too far back? Is there any real problem with moving the stock crossmember back? Could a V8 crossmember be installed (I don’t know how much different they are from a Model A crossmember). Some of these probably seem rather stupid to most of you but I’m new to this.
Pete and Jakes axle brackets are, iirc, 7" axle center to spring center. You should be able to work it out for yourself with what you have armed with that info. Chris
I don't think the Model A frame rails extend beyond the stock rear crossmember. Coilover rear suspension is a good alternative, as they can be positioned behind the stock crossmember. I like triangulated four bars to position the axle front to back and side to side, with the coilovers controlling up and down.
I used a triangulated coil over kit on an 8 inch rear end. It was an easy install, and rides very well.
It can be done , But by adding 2 inch to frame rearward Then , there is a body mount on The rear crossmember would need to be added in Original location, in this case bed mount . No big deal to fab mount. Then close on centering wheel /tire in fender if being installed
This one came out of Canada. I created some leg room by using a V6, removing the water pump, and moving the engine all the way forward. You can see the reversed firewall in the photo. Stupid car...
There is enough room between the crossmember and body lip to add a suicide perch on the back of the Model A crossmember to put the spring behind the axle. Same distance as Ford used '35-'48. Due to it's configuration, the crossmember needs to be reinforced. A tube crossmember could done instead.
I like that Rich! SD, if I ever had the funds to do it (body n paint is already done on mine) I would take 6-10” out of the front of the bed and stretch the cab back to match. I had a friend take about a foot off the back of his closed cab ‘cause he thought it would look better. And it did, he left the cab alone, just lopped some off the back.
I extended my frame 7.5" and used the stock crossmember. It was a fair amount of work and pinches the rails inward slightly if you do not widen the crossmember slightly. Rich (above) has what looks like a good idea (clean; fast; doesn't change stock dimensions) though I would have turned the two support pieces 90 degrees.
My kid used a later model '37 up spring with the suicide perch which effectively lowered the full fendered car just right.
That’s pretty much what I’m thinking of Rich. I know that there are numerous reasons that coils are easier and better but I want to keep a more stock appearance.
Mine has the suicide perch with a 40 model rear end and spring. One of these days, I will get pictures of the rear end setup.
28 RPU- what you want to do is pretty basic. In my case I will extend the rails the distance of 40 Ford rear mount as I am using those housings and Model A x member and spring. Will also step the frame a bit as my roadster body has no floor to deal with at this time and I want to lower it. You say you want to stay with a transverse spring, Rich’s rear mount will raise the rear of your car (if you use a model a rear spring) as the spring mount is lower than the stock x member mount location. I’m sure this pic is in the “under construction stage”and will get a little more support added. Looks like a real easy and simple fix.
Rich's solution is probably the best for your situation, and mount the shocks on the front side. This is a '29 I fabbed a new rear section, and the dimension is 7-1/2".
Their was no thought to use an A spring; plan was to use an easier riding '37 up spring on a later banjo rear axle to lower the rear of the car. My kid (not me) built this and the mount is complete; the plate extends to the front of the crossmember and is tied into the tubes that extend to the frame rails. Can't just hang a perch on the back edge of the A crossmember. Marty's set-up in the preceding post is a neat clean way to do this. Another idea, if you want to cover all the bases, would be to incorporate an adjustable suicide perch like Bob Bleed does on his frames.
One thing about it when you get Rich B and Marty involved in it you get proper answers that you were looking for rather than off the wall suggestions of what someone else wants rather than what you want.
All good ideas and very, very helpful, thank you. Marty, I would say that what you have built there is pretty close to perfection but at least for now, way beyond my skill set. Very helpful pictures, they show far more detail most do. I would have a complication that since mine is a pickup the step up would create other issues. 1949, you are correct and you are not correct. It is true that Rich’s perch is lower then the stock crossmember and would actually lower the top of the spring, but it must be remembered that switching to a behind the axle spring allows for a drop that is significantly more then the perch would reduce it (if that makes sense). When all factors are taken into account on my build, Rich’s perch (technically Rich’s son’s perch LoL) is the best all around solution. I will look at the Bob Bleed perch too.
Being a pickup would make it easier, and if you are not using an A rear spring, the kick up would not cause a problem. Mine runs a quickchange so the high arch spring is a necessity. The first set of pics are of mine, the second set are of Mitch Kim's. note the bed floor in his, it only required a small hump in the middle, and with 37-41 spring there would be nothing.
Back in the late 1950s,,I used a 28 A frame with two custom crossmembers{ the front one ,I moved forward/and used a box tube=spring infront of axle { I used a 48 front axle { stock ford factory axle in had a 3inch drop also} with mods to,split wishs n custom spring}. I fab. a tranny cross as well. With a few extra braces.<. Rearend I replaced with newer open rear,an moved forward so ModelA spring with removed 3 leafs was then behind axle and down some. I did not Z anything,was not needed. Thinking back=I should of made tranny cross un-bolt ,like I had done for engine mounts. This pic was from refresh about 20 years back.
Looking at your very last picture (which due to the angle does not make it possible to see all the details) I cannot se that the frame was extended. It looks like the crossmember is in the original location (I’m not saying it is, I’m saying it looks like it).
Not the greatest picture of the perch on one of Bob's frames; but anyway, the perch bolts onto the vertical plate and can be located up or down to suit your desired ride height during construction and afterwards.
Dana, if I’m understanding you correctly you kept the rear crossmember in the original location and moved the axle itself forward about “? I am probably NOT understanding you correctly though LoL. If you did move the axle forward I would be interested in seeing some pictures of the finished car to see how you worked with that. Thanks
The Jalopy Journal
