4 Link rod end question

I'm fabbing my own parallel 4 link on my project and have some questions about rod ends. The links are going to be short, about 18 inches, and the car is light and fenderless with just a stock 350 for power. ALL SHOW NO GO. It sure would be easy to use clevis' for ends. I've seen it done but are they strong enough for the rear. I'm concerned that regular rod ends like shock absorbers will bind or if heims are really the proper way to go. Please point me in the right direction. Thanks

 

I have a friend with heims all over the place on his T.

I am using heims in some locations but for my 4 link I have switched to Urethane bushings, they will be quieter in operation than the heims.

 

Heims are ok on the Axel on the frame run urethane less noise. I perfer all unrerthane but have been know to run what I have laying around. Nothing should bind in any travel

 

Thanks for the quick reply. I guess nobody thinks that clevis ends are a good idea. I've got some pictures but haven't figured out how to post yet. Will do that today.

 

I want the car to be safe. I don't want to be wondering about the clevis' breaking all the time. I'm not sure about the weight of the car when finished. 46 ford pickup body,2x3 frame, 350/350, 9inch, no fenders. 2000lbs maybe?

 

Using a clevis either requires something to twist/flex/bend, or the joint has to be sloppy enough to avoid that binding. The same is true of the 4-link itself. Even on race cars people get away with these binding situations. But in some respects racing is easier on parts than the street. And while people do get by with binding suspensions on the street, it's basically a matter of how hard and how many times you can hit something with a hammer before it breaks. Even with greasing and dust boots, rod ends and clevises(yes, even the good/expensive ones that should be used in suspension) don't take long to loosen up. Although some wear isn't unsafe, on a street car the noise can be irritating. As was suggested, urethane takes care of binding/misalignment, doesn't wear quickly, and provides a little isolation between the car and road. Too soft a bushing, and/or one with a large diameter, will cause sloppy suspension control. Aftermarket/performance urethane bushings normally aren't oversized like OEM bushings, and they are normally firm to hard, so that shouldn't be an issue.

 

Thanks Al. You just made up my mind. The after market urethane bushings sound like the right choice. It's buggy sprung in the back. Should a torque be considered or not?

 

Sorry Al, I ment to say "TORQUE ARM"

 

It doesn't really matter. The situation is the same with a torque arm suspension. When one wheel goes up or down relative to the other there would be misalignment at the pivot points.

 

Sorry, I don't understand the question.

 

Hey Bulldog, I certainly didn't mean to suggest that you were offering up unsafe or bad advice. I was the one that was worried about the safety of clevis ends. Al, the torgue arm I'm refering to is possibly one arm from the top of the rear differential forward in addition to the 4 link. Is it necessary or overkill?

 

A torque arm serves no purpose on a 4 link. If it is triangulated, even a panhard bar is not necessary, however,a parallel link setup will need one

 

61bone, Thanks for the info. I initially went on a " let's see your 4-links" technical thread and there was just too much info. Thanks to all you guys for making it simple. I will make a point of posting some pictures.

 

By buggy sprung do you mean that you are using a single leafspring pack like a stock model A?

 

I always look at it this way when I build anything .
Would you trust it enough to drive 1000 miles with you family in it ?
When you start to ask the question , Can I use this , you already answered your own question !
Alway be SAFE and any cost ! One day something might go wrong and you surely don't want that part to brake or let loose with your loved ones in the car ! Do it the right way the first time so you can always enjoy your hotrod the way it should be driven !
Just something to think about !

Jim

 

Yeah 28, It's a single model a spring hung behind the rear end.

 

Jims right! Chromoly heims or threaded bushing ends are a small cost compared to a hospital bill.

 

With a single rear spring pack you will still get left to right shift on the axle because of the shackles so a panhard or watts link is always good to have to keep the rear end in place.

 

RetroJim, You are absolutly correct. I've ridden in other guys cars that just felt dangerous. I don't want to be white knuckled every time I go out. I sure don't want anyone to get scared or get hurt.

 

When I build a rear suspension of any type I tack all of the brackets in place then put a floor jack under the axle and raise and lower it through the full range to check for binding. If all looks good, then finish up the welds. I use the bushings from AFCO or Smiley's Racing parts. They hold up well and are inexpensive.

',ve never seen a four link setup with a buggy spring, seems like a lot of places for stresspoints.

 

I've had several hopped up model a's, all 4bangers but this is my first frame up build and I want to keep it simple and safe. It's a father son project and safety is job 1.

 

I have to wonder about putting the spring behind the axle with that arangement. I have one under mine and was thinking of doing it, but I would think that it would add more stress to the four bars, as the load isn't more or less balanced above the axle. But I have to agree with using bushings on both ends of the rods. They can give a bit which should help the potential binding situation. I also placed mine inboard of the frame, rather than outside it. I figure the closer to the middle, the less twist it had to make as it cycles.
Good Luck.

 

Carol shelby has some good suspension books out. They go into theory and math involved. IC, pinion angel etc

 

Ditto

Ditto this too. People put up with the lateral movement, but the car will feel sloppy.

 

I made my own 4 link too, i used a panhard bar to keep the axle centered. I wouldnt think a single buggy spring would have any different effect than running coilovers(i do). I REALLY agree with the guys telling you to run poly bushings, they make a hell of alot less noise than the heims.I'm running full heims on a jeep I built, you can feel every little stone you run over. I have a couple pics of the 4 link on my home page.
Good luck!!

 

I fabbed my own triangulated 4 bar with a buggy spring recently. If you'd like to see what I have and some of the possible things to watch out for send me an email; I'm probably not too far away from you.

 

At least if you are running heim's you might run them on the frame end of the link and the bushings on the axle to take the vibration from the road out. That's what I did so they were ajustable for the allinement shop. And dont forget to grease your urathane bushings!

 

I hope So-Cal Speed Shop aren't dirty words for hambers but their catalog shows some pretty nice urethane bushed rod ends that don't seem too expensive. BillM I'll definately check out your triangulated set-up. I'm thinking all the rods will be the adjustable urethane bushing type.

 

David Chandler, My 4 bars will be about 28" apart. I was thinking that would be kind of narrow but I'm comparing them to the mounting points in a stock configuration for a model a wishbone which are almost at the ends of the axles. I'm probably comparing apples and oranges. Does anyone else have concerns about the spring being mounted behind the axle?