Rear suspension problems....

HaveII

Founding Member
Sep 9, 2001
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Houston, TX
I am in the process of trying to figure out what I want to do about getting traction. My right leaf spring looks like it is bowed or twisted outward on the passanger side of the car and all of the rubber is rotted and looks original to the car. I am considering two options which would both include weld in frame connectors.

1. I could buy new leaf springs, drag shocks, and lift bars, but wanted to know how effective this setup is and what the limitations are. Is it the bushings and pads between the housing and leaf springs that are hard to find replacements for?

2. Maybe a pipe dream, but you never know. Remove the leaf springs, open up the wheel wells another 2 or 3 inches under the car, build a half frame, and install a 3 link system. I inquired about a 3 link from a company and got the following responce:

We have two links that attach at the front to the front leaf spring purchase and at the axle they pass through a block that attaches to the axle. The coilover is attached to the rear of the axle block. The third link attaches on the right to the inside of the frame and on the left to the Axle block. This third link keeps the axle centered. The upper coilover mount is a u-shaped bracket that attaches to the outside of the frame rail. The problem with using this on a stock Mustang II is the car has unit body construction so the frame rail is inadequate to attach the coilover and centering link to. You would have to beef the unit body frame up to handle the increased load.

We designed this to be installed on Kit cars and Street Rods which used the rear leaf spring system from the Mustang II. These cars have a full frame to handle the loads that accompany this system.


I wrote back asking for more information and got this responce.

Look directly above the rear of the axle above the leaf spring. What is there to attach the upper mount of the coilover to?? The centerline of the upper coilover mount will be about 2.5 inches back from the rear of the axle tube. We also connect the right end of the centering link to the inside of the frame at the same mounting bolt of the upper coilover mount. I suspect you will need to add structural strength to the frame at this point to support the coilover load.

Anybody done something like this? Is this a good option? Pictures? The car is a weekend toy that does see some street use.
 
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I'm considering various options for my car's rear suspension also.

I transport totalled cars to auction for a living, so I get a chance to look under all different makes and models and see how they're designed.

I'm seriously interested in the ladder bar setup I see on certain types of SUVs.
A large, hollow-tube ladder bar, maybe 3 feet in length, and 1.5" diameter, attaches to the frame with a simple bracket and poly bushings. On the other end, the ladder bar attaches to the axle with a narrow mounting pad and 2 large bolts, fastened to a flat bracket that's welded to the housing. The shocks attach to tabs protruding from the backs of those flat brackets. There's a hollow 1"-1.25" stabilizer bar running from the driver's side frame rail over to the passenger side of the axle housing. (The stabilizer bar is parallel with the housing when the car is at rest.)
There's a crossmember bolted, or welded to the floor pans, connecting the rear frame rails together, and the tops of the coil springs rest in pads welded to that crossmember. The bottom of each spring seats in pads welded to the housing.

It looks to me like I'll be scavenging most of the setup from a junkyard, and then fabricating the crossmember from rectangular tubing. The only thing I'll have to take careful note of, is spring height and shock length.

It seems like a simple setup, that would inhibit rearend wrapup, and it appears to be strong enough for what I need it for.
Anytime I customize something on my car, I try to use stock-type pieces from another production vehicle(preferably Ford), so I'm able to order replacement parts in the future without hassle.
 
Blue Thunder said:
I'm considering various options for my car's rear suspension also.
.....
I'm seriously interested in the ladder bar setup I see on certain types of SUVs.


Whould this be a front wheel drive SUV?


There's a hollow 1"-1.25" stabilizer bar running from the driver's side frame rail over to the passenger side of the axle housing. (The stabilizer bar is parallel with the housing when the car is at rest.)


This is known as a panhard bar.
 
Blue Thunder said:
I thought your question was a joke..?
FWD vehicles have relatively weak(coat-hangers and string) rear suspensions, as they're not designed to handle stresses associated with a powered axle.


Not a joke.

I'm wondering what SUV, or actually any vehicle, comes from the factory with ladder bars (in function) on a drive axle.

I've seen mini vans and SUV looking things with front wheel drive that had setups as you describe but nothing with an actual drive axle.
 
To expand, I've seen the ladder setup used with a good sized tube as an axle but the tube was designed to allow enough twist for somewhat independent wheel movement. The tube acted as a stab bar.

Can't have that kind of movement with a drive axle. I know NASCAR does it, calls it a truck suspension, but their on a track.

The only exception I know of is the old Chevy truck, the bar ends hooked up towards the center of the frame.
 
I was planning on hitting my favorite junkyard's SUV area and see if they have the model that I inspected when it was on my truck. It's definately a RWD or AWD vehicle, not sure if it's foreign or domestic, though. I will know soon enough.
It looked to be a very simple, but very stout setup.
 
Blue Thunder said:
I'm considering various options for my car's rear suspension also.

I transport totalled cars to auction for a living, so I get a chance to look under all different makes and models and see how they're designed.

I'm seriously interested in the ladder bar setup I see on certain types of SUVs.
A large, hollow-tube ladder bar, maybe 3 feet in length, and 1.5" diameter, attaches to the frame with a simple bracket and poly bushings. On the other end, the ladder bar attaches to the axle with a narrow mounting pad and 2 large bolts, fastened to a flat bracket that's welded to the housing. The shocks attach to tabs protruding from the backs of those flat brackets. There's a hollow 1"-1.25" stabilizer bar running from the driver's side frame rail over to the passenger side of the axle housing. (The stabilizer bar is parallel with the housing when the car is at rest.)
There's a crossmember bolted, or welded to the floor pans, connecting the rear frame rails together, and the tops of the coil springs rest in pads welded to that crossmember. The bottom of each spring seats in pads welded to the housing.

It looks to me like I'll be scavenging most of the setup from a junkyard, and then fabricating the crossmember from rectangular tubing. The only thing I'll have to take careful note of, is spring height and shock length.

It seems like a simple setup, that would inhibit rearend wrapup, and it appears to be strong enough for what I need it for.
Anytime I customize something on my car, I try to use stock-type pieces from another production vehicle(preferably Ford), so I'm able to order replacement parts in the future without hassle.

This sounds something like I had in mind and the junk yard option would make it cheaper. The thing I liked about the setup I am checking into is that the front of the ladder bar (sorry I don't know the technical term) hooks into the same mount that the front of the leaf spring attaches to. Please post back if you find a potential vehicle that might be good to rob some parts from.


Still hoping to hear back from some people who are using modified leaf setups about what kind of times they are getting at the track (ie: 60 foot, 1/8, and 1/4) and where you would draw the line for it's limit.
 
this setup
old_coil.jpg
 

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Yep, that's the one.

The only thing I may change when I adapt it to my car is using larger diameter tubing for the ladder bars. (I'm thinking during very heavy acceleration with good tires, the stock-sized bars may be forced to bow under compression, and that would be a bad thing)
 
Is this setup welded to the axle housing or does it bolt on? Would those springs be too heavy?

Blue Thunder:

Any idea when you plan to start working on this? I sure would like to follow the project when you do.

Also: Any idea what a junk yard might charge for something like that?