Ok, I've seen a bunch of A rods with solid mount control arms, but you guys have convinced me this is not the safe way to go, especially when this is going to be my wifes. My plans now are to have two outboard control arms mounted low on the axle tubes running parallel to a mount on the frame rails, and one mounted above the differential nose running to just above the t-5 tailshaft. Gonna use equal length arms, though the center one will not be in line with the outer arms, and mount them with GM A-body rear control arm bushings. I'm going to put the Model A spring over the differential as it was origonally, and don't plan on using a panhard bar. Anything wrong with this picture?
Look at my car build pics and you will see a suspension that doesn't work properly. It had a dose of rear steer that was very noticable in a long left turn and a horrible body bobble from road irregularities. I designed it. I have since changed to a ladder bar type suspension using the same four bar brackets and forward mounting points. It drives SOOOOO much better. Granted, I'm using coil over shocks instead of a rear leaf spring and I must have some kind of panhard bar. Take a look and learn from my first experiment that didn't work very well. http://www.jalopyjournal.com/forum/showthread.php?t=394342&highlight=marmonherrington
The pivoting radius rods won't bind the axle side-to-side like a split bone setup, so you probably should run a panhard. You could also make an A frame for the upper link (point at the axle). That would keep the housing centered just fine.
I thought about the ladder bars, but have a couple of reasons I chose not to go that route. First, I really don't see any difference in the ladder bars and a single control arm mounted solid to the axle tube, neither will allow the axle to rotate as one wheel rises, in effect creating a sway bar effect with the rear end, and second, my goal here is to have this build look like the 'kids' did it in the '50s. They would have just split the wishbone, and that's the look I'm after. Am I not seeing something that makes the ladder bar work better than the solid mounted control arm other than strength? The look I'm after is also the reason I would like to avoid the panhard bar. My thinking is there is very little room for side to side movement with the spring mounted as it was on the banjo rearend. Mr. Ford built them for years without seeing the need for a panhard. I don't see how the wishbone would prevent the side to side motion. I appreciate the help here, if you think there are flaws in my my plans, tell me, convience me, I only want to build this once if possible.
Oops, I misunderstood you. I thought you were pivoting the links at the axle ends as well (GM control arm bushings?) If not, then no, there is no difference between the split wishbone and a ladder bar. Why did you say in your first post that you were convinced this wasn't a safe way to go? The control arms being mounted rigidly to the axle is what eliminates the need for a panhard bar. If you have bushings at both ends, the rear axle will be much freer to move side to side.
The links would pivot at the axle ends, my current plan using rubber bushings from GM rear control arms, at each end of the links, and the center link aswell. My reason for not feeling the ladder bars being any better than a solid mounted arm is the triangulation of the ladder would not allow any rotation of the rear end when one side elevated, which is the same effect the solid mounted arms would have. Isn't this right, or am I missing a pivot point on the ladder bars? In the origonal configuration, the wishbone intact, the only thing I can see that prevented the rear end from side to side movement is the spring mounting, which I was counting on in my plan to avoid the use of the panhard. Not intending to sound argumentitive here, I just have a picture of what I think is happening in this type of suspension. I've been wrong before, I may be now.
If you run ladder bars you need to triangulate them and mount the forward point of both bars as close together as possible. This will allow the axle to rock more like the original set up. I have a different set up but use an original A spring without a panhard bar. I get a little bit of sideways movement but not subsatantial. Probably only 1/2 inch on hard cornering. I know this because the inside of my tyre clears the body by 1/2 inch and on very rare occasions, it rubs slightly.
That's exactly my thinking on ladder bars. I see people putting heim joints on ladder bars at the axle end, why I don't understand except maybe to allow some side to side movement. About a half inch, maybe a little more is what I expect to see without using a panhard bar, heck, there will be some movement with a panhard because it travels in an arc, depending on the angle and how short it is, even with a panhard you might see a half inch of movement. I appreciate everybodys help here, I'm still looking for a good reason not to follow my plan.
I've started building the three point suspension, ready to put the fabricated spring mounts on my S-10 rearend. I need to make a sharp 90 degree turn with the brake line right out of the wheel cylinder. Is there a 90 degree fitting that will mate to the flare in the wheel cylinder? There's just not going to be enough room to put a 90 degree bend in the brake line to miss the spring once it is mounted.
Haven't posted on here is quite a while. I finished the 3 point rear suspension, infact, I've been driving the A on my street for about a month now working out a few problems with the front end and doing a little engine tuning, and have even shown it at the Rust-O-Rama held here in Salem at the State Fair grounds. Had lots of interested folks checking it out. I'm happy with the 3 point to this point. I see one problem that may cause me to decide to make some changes. I put the rear pivot point on the center arm low and toward the front of the differential so it wouldn't be so noticeable from the rear. This may become a problem because instead of pulling on the arm when I get on it a little, it's far enough in front of the outer pivots that it's in the lift portion of the arc instead of the pull, if that makes sense. Still, it seems to work well so far, not a lot of differential rotation, but would rather see none.
Been driving this thing for about a year now (just licensed it last month...) and am really happy with the three point rear. Still have the problem with excessive lift, or rotation, of the differential. I'm going to extend the center link back a few inches and up about 1 inch, hopefully this will stop the rotation. Need to put shocks on it. I want to use friction shocks, which I would like to fabricate myself. Any suggestions on design?
All three links need to be of equal length, if you want to stop pinion angle change. The more that the center one differs in length from the outside ones, the worse it will be. I'd run hydraulic shocks. There is a good reason that friction shocks don't exist anymore.
I really like the rear set up! Looks nice. Really simply too, and that might be the way to go for my, if I can find a nice A bone. @need louvers? Posted a couple posts on friction shocks on his "bucket of ugly" threat. He knows his shit/stuff, but i I dont know how to find it in his gigantic tread. The @ in front off his user name is a test, because it seems that doing just that makes the user get a notifikation.
Dead right on the pinion change Gimpy! Also the spread of the front mounting of the bars will affect pinion change, too. Personally, had I done a similar rear suspension to this, I would have dispensed with a third arm to the top and run a single hairpin down the center, hinged at the u-joint ala "torque arm type suspension as Kurtis and other companies did years ago. Gimpy, you and I are usually in a pretty close lock step with stuff, but where we do differ is with friction shocks. For lighter cars such as my bucket or even some Model "A"s, I find them very effective and quite adjustable. I can't begin to explain the difference when I did the pair on the front of the 'Bucket, and I have adjusted them tight, loose, and in between and the difference in each adjustment is pretty dramatic. I have found a happy point where they work and ride perfectly! If hydraulic was completely an issue, a pair of Girling lever shocks from under a M.G. Midget might be another good alternative, too. If someone just wasn't going to live without tube type shocks, Non-gas KYB lowered link pin VW fronts always seem to be about right, if not just a shade stiff. Thanks for the nod Volvobrynk, I didn't get a notification on this one, but I just happened on it as I was cruising the main board. I guess the @ stuff doesn't work here.
[/QUOTE]Thanks for the nod Volvobrynk, I didn't get a notification on this one, but I just happened on it as I was cruising the main board. I guess the @ stuff doesn't work here.[/QUOTE] We need too give credit, where credit is do. And you know you shit/stuff, so why not send him to you for the best advice. And what do you mean that it (@) dosen't work, you found this, and was the first to reply after my post. :-D And out of all threads, abd the huge amount of new post, you found the one you needed to find!
I don't think I am explaining the problem I have with the center link well enough. The problem isn't just a couple of degrees of change in the drive shaft/pinion angle when the suspension compresses, I can live with that. What is happening is the center link mounting point is forward of the axles, while the outer links are almost directly under the axles. The differential wants to rotate on the axles under power. The center link rear mount is not at the top of the arc the differential is trying to rotate on, it is at the front of the arc, so instead of being pulled against, the link is lifting. The few thousands of an inch of play in the heim joints is enough to allow probably 6 or 8 degrees of rotation. Simply moving the mounting point closet to vertically above the axles will put it at or near the top of that arc, eliminating the rotation of the differential. If I remember correctly, the links are all 33 inches, plus the length of the two heim joints. Adding 3 inches to the center link I realize will cause the pinion/drive angle to change on suspension compression, but probably not as much as is happening now. As it is now, when you put power on you can feel the link coming tight, kinda like jerking on a chain.
As far as friction shocks go. It is purely for the 'look'. I am running without shocks now, I've had this little jalopy to 80 and no problems except a little bit of front wheel bounce. I would like to eliminate that, and like the look of friction shocks. I don't want to buy them, I want to fabricate them myself, as I have almost everything so far. I kinda like to ones need louvers? posted pictures of except I will not use aluminum. My objective on this project is to have something that looks like what a teenager would have put together in his folks driveway 60 years ago, he wouldn't have milled aluminum. They look great though. I like the spring, an interesting look I plan to incorporate in my design.
Question for need louver? on his design. Do you have a problem with the outer friction disk rotating the spring and loosening the adjusting nut? I don't see anything to keep it from rotating with the arm movement. I can see myself driving down the road and shooting that nut through someones window.... Is this something I need to worry about?
I've decided to go with hydraulic shocks, tube type, on the rear. I sat out in the shop studying where to put the frictions and I just don't like any place I came up with. I'll use '74 mustang ii front shocks. They've got a little over 3 1/2 inch of travel, and are only 11 inches fully extended. They will be at a bit of an angle, maybe 15 degrees off vertical, that will give slightly more rear end vertical movement, close to 4 inches. still going with frictions in front. Will build those in the next week or so.
I've cleaned up and pumped all the old fluid out of the hydraulic lever action shocks that were on the Jalopy when I bought it, I have 3 that work fairly well. I put 2 of them on the front, work pretty well. I think I need heaver fluid than I replaced the original stuff with, it was 10 wt. I have a little trouble with the left front wheel dribbling at times. going to try 40wt hydraulic fluid.
I've had this three link suspension on for 3 summers now and it has generated a lot of interest at shows. I've watched people actually lay down and slide under taking pictures of it countless times, I expect to see more jalopies with this.
Decided to get rid of the stock steering box and go to cross steering with a mid 60s Chev pickup box. Built new tie rod and drag link. Also wanted something interesting other than a couple of universal joints to that box, so designed and built chain drive. I've been running this since around July last year, works great, and talk about interest, probably thousand pictures have been take of this setup at the cruise-ins I've attended.
Had my Jalopy at the Winter Rod and Speed show in Albany Oregon in January and was approached by a promoter of the Portland Roadster Show, said he wanted my Jalopy there...What a shock! Must have looked like Gomer Pile standing there with my jaw on my chest. Entered it in the Traditional Hot Rod class. What a privilege to be there, thought I was on top of the world. On Sunday had to wait until after the awards ceremony to get it out. Holly Shit! They called my name. Won Best In Class for Traditional Hot Rods!!!
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