Rear suspension question

I have a 37 Chevy Coupe, it has a 73 Camero rearend with leaf springs. Springs are in good condition, problem is I bottom out fairly frequently, usually when there is a dip in the road like where a trench has been cut and refilled but at a lower road height. Basically both back wheels have to drop at the same time. Anyway rebound has me into the bump stops. So I am trying to figure out a way to fix it.

My question is, can coil over shocks be used effectively with leaf springs on my set up? If so would they cure my bottoming out issue? if the answer is yes to those, then what # coil over would I need? If the answer is no to the combination, then any ideas....LOL?

Thanks,
Brett

Sounds like the problem is in the design of the rear frame if it bottoms out that easily!!! How much travel do you have between the bump stops and housing???

A couple pictures of what your working with would help..I'm with Dave on this that coupe isn't that heavy(2700#) 73 camaro (3100#). Somthings in the wrong place.

I have the bump stops removed now, and in the right circumstance the driveline will now hit the floorpan at the rear yoke. I have about 5"-6" between the yoke and the floorpan sitting still.

Like I say, it don't do it real often, but will hit when the rearend unloads and then rebounds. But both sides have to drop and rebound together, one wheel dropping and rebounding will not hit anything. I am wondering if my springs are worn more than I think they might be. Nothing is broken.

Air shocks will solve your problem but stiffn the ride. I had a 38 coupe and used chevy van springs longer and wider. but rear was narrowed

Seems to be a common problem, with this vintage Ford. The frame on these cars is too close to the body floorboards, and when you change to paralell springs , the rear end sits way to high. When you use a lower/flatter spring you have the rear or other parts hitting the floor boards. I have a 40 coupe with the same problem. My car always rode rough, going over bumps. One day I was looking over the rear suspension, and found a shock, that had broken off at the top mount. I removed both shocks and let the car off the jack and was surprised how much lower the rear of the cas was sitting. Turns out the car was riding on the two shocks which were bottomed out, and holding the car up for clearence. The guy who built this car apparenrtly could not figue out the problem either. With the car sitting just using the springs,the top of my 9" Ford rear has about 6" of clearence, till it hits the floorboards. I've talked to several people, but no one really has a good answer. I was concidering air shocks also which wound be an easy solution, if they make them short enough for this application. Gabriel does list many models but haven't had the time yet to call them.

I was giving air shocks a consideration and then thought about coil overs. But after looking at the shock angle I am not sure coil overs would be the way to go. So will probably just stick a set of air shocks under it and be done.

Ditto.....Alot less money also !

If the shock angle is too radical, and there's not enough suspension travel air shocks will be nothing more then a band aid!!!! Air shocks might stop it from bottoming out but ride and handling will suffer......

Not sure if it is too radical, or even beyond what angle is too radical. I could move the upper shock mount to decrease angle, but that would make for a very short shock. I am currently running a Napa 94005 gas shock, which is a pretty short travel shock. Sitting still the shock is just about the center of its travel range. Not even sure if someone makes an air shock that would work.

most shocks will only have 4 1/2 to 5 in of travel. pumpkin hitting the floor is common. especially with a 9 in or 10 bolt. just the price we pay to set low :) . shock angle should be 15 to 30 degrees. shocks mounted straight up are pretty much useless. if your springs are loaded and fairly straight you might try a heavy first leaf ( short one ). it will limit spring travel.

Gasser it :LOL::LOL::LOL:

Oh, NOOOO, can't gasser......LOL gotta keep the low and mean look. I will start calling shock companies tomorrow and see if I can come up with a set of air shocks that will work. Part stores can't do anything without knowing what car it is on, and in this case that makes no difference...lol Always something.

You have 5-6" freeplay and teh yoke hits the floorboard? You must mean 5-6" with the car up on jackstands and the rear hanging free, right?

or maybe the pinion isn't the right offset for the drive line tunnel--

no bumpstops!!!!!

And sounds like shocks are totally wiped and/or bottoming out

Actually, I have 3.5" between the rear yoke (U-joint) and the floorpan while car is sitting on jackstands compressed suspension just as if it were sitting on the ground. Pumpkin to floorpan is substantially more. The way the 37 floorpan is designed it has plenty of room for the pumkin but there is no tunnel for the driveline. I took the bumpstops out just to look at distances. Shocks are brand new Napa 94005 gas shocks. The shocks compressed are 10.125", fully extended are 14.625 (per spec sheet). With car on jackstands and suspension compressed at ride level the center to center on shock hoops is 12.5". Both shocks tilt forward at about 30 deg.

If you put a Ford 9 inch rear in it you will pick up about 2 inches of driveshaft clearance as the 9er ford pinion is probably the lowest pinion of any out there--also I believe the yoke will be fourther rearward which might possibly help also

but to stop bottoming out you will need bump stops , a stiffer spring rate and maybe more tunnel clearance

Ride quality.......
You have to keep it simple. First the majority of the overall ride quality ( what you feel in your butt and your back ) while driving down the road comes from the back of the car. What you feel in your hands and your feet comes from the front of the car.
In order to maintain any kind of a descent ride quality you have to have a minimum of 2.5" of compression strok and 1.5" of extension stroke. That is minimum and it has to be on the money. Ideally you will want 3" of compression and 2" of extension stroke. This is on a mid to full size sedan. If you dont have that then there is nothing you can do to get a descent ride. If the stroke is shorter then you have to limiting suspension movement with heavier springs and stiffer shocks.
Once you have the suspension set up and you KNOW you have the proper amount of travel until it bottoms on the bumpstops, then you can turn to the shock absorbers to get them working with the suspension and the stroke of the car. If your car now has 3" of full compression stroke but your shock only has 1.5" of compression stroke... then you are going to be bottoming the shocks out, eventually killing the shocks and more than likely ripping a mount off. You have to make sure the car hits the bumpstops... DO NOT use the shocks as a bump stop. Most of the 35+ cars I have crawled under could simply benifit from having the lower spring mount/shock mount plate flipped upside down and swapped from side to side. This should put the shock mounting hole going down, not up. This will allow you to run a longer strok shock.
Next is shock angles and shocks... In the rear of a car with the typical straight axle, if you get your shocks between 15 and 21 degrees you a re fine. Anything over 25-30 degrees and your shock is probalby not even working. Also keep in mind... if you purchase a 20 dollar shock then you need to expect a 20 dollar ride quality. In a properly set up car, the only job the springs are there for is to hold the car up... the shocks are the brains of the suspension and control everything.

Tony,

A couple of questions for you... first, shock angle. MrChips mentioned his cars shocks were angled forward 30 degrees. Seems to me that the shocks would possibly be more functional angled side-to-side. My thoughts are that it would help keep the car from going into excessive lean angles in the event of a swerve, and aid in a more stable ride? With leaf springs there may be a little bit of side-to-side movement because of looseness, or wear in the spring shackles and bushings and I figure the shocks would possible keep this movement to a minimum.
I have a problem with a suspension set-up I have been working on with my car because of lack of room between the frame rails. I haven't touched it in a while because of helping other people with their projects. One of these days I hope to get back to it and would like to get it set up correctly.
I have noticed on several factory suspensions that one shock is angled to the front and the other is angled to the rear. Is there any preferred angle, front, back or sideways for the shocks? I set mine up angled sideways but I was told that the angle should not be more than 30 degrees by the vendor that I bought my coil-overs from. I have some issues trying to set my triangulated 4 bar before mounting the shocks, but it appears that my frame is too narrow.
I didn't mean to hijack the thread, just trying to get good information.

Shocks work best when mounted upright


http://i65.photobucket.com/albums/h2...ang/Shocks.jpg


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Originally Posted by roadster32

Shocks work best when mounted upright


http://i65.photobucket.com/albums/h2...ang/Shocks.jpg


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That's very good picture, Steve, saved for future reference. Thanks for the crystal clear presentation.

Quote:

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Originally Posted by roadster32

Shocks work best when mounted upright


http://i65.photobucket.com/albums/h2...ang/Shocks.jpg


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Problem is suspensions move in an arc,not straight up and down.

I have noticed on several factory suspensions that one shock is angled to the front and the other is angled to the rear. Is there any preferred angle, front, back or sideways for the shocks? I set mine up angled sideways but I was told that the angle should not be more than 30 degrees by the vendor that I bought my coil-overs from. I have some issues trying to set my triangulated 4 bar before mounting the shocks, but it appears that my frame is too narrow.
I didn't mean to hijack the thread, just trying to get good information.[/QUOTE]

They did that on leaf spring cars to help control spring wrap up on accel & decel.

If they work best straight upright, why do you never see them mounted that way on a factory production car? Inquiring minds want to know. i don't recall ever seeing a shock mounted straight upright on anything. Thinking about it, I do recall seeing them mounted straight upright on a bucket T. I really would like to know for sure.

Quote:

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Originally Posted by roadster32

Shocks work best when mounted upright


http://i65.photobucket.com/albums/h2...ang/Shocks.jpg

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