1947 Chevrolet Fleetline - 4 Link Install Update (PICS)

Hey guys, I managed to tack weld my suicidedoors.com 4-link kit on my '47 Fleetline frame and rear end. Check it out and please provide feedback before I do the final weld. I lifted it and there was no binding. Of course, I would add support to the ends of the bars and box it. This is just a mock up...Thanks...

 

Looks pretty good to me except I would probably box in the mounting points to make it all as strong as you can,the tall ears on the rearend may try to flex...does the pinion angle change much when it travels?
Also I am curious as to why you didn't use the stock mounting points on the rear housing(uppers) It would have been pretty easy to fab a couple of tabs,cut off the bushed ends of your bars and put it all together. Then there less welding on the housing.

 

Thanks for the info. I adjusted the pinion angle to be -2º (-4º for the ****** tail shaft and +2º for the rear end yoke). I will box it all.

I didnt use the upper stock mounting points because I would of have to make a crossmember for them and thus protruding right up to the rear seat.

Thanks...

 

are you bagging it??

 

Hydraulics.

And no, no hopping!

 

That looks real close to how my friend did the four link on my truck. It works great. No binding, no noise, smooth ride. It can get a little bumpy when I'm getting low on fuel and the back of a truck doesn't weigh much. Your Chevy should ride awesome! E

 

Those are good looking links, I also have been ordering brackets from Suicide doors.

Are you going to be running small wheels like fourteens? I'm wondering if you need to C or notch the frame to get low enough. Which could mean more travel on your four links, more than in your pic.

 

Yes, Suicidedoors rocks!


I am pondering if I should go with 15's or 14's. I have 15's (stock '49 - '54 rims) and I want to go with a fat white wall. Also, the rear end is a posi 10-bolt off a Chevelle.

Thanks for pointing it out about the c-notch: How low would the car look when the axle rest on the frame rail? In many images via the Web, I have seen a lot of folks notch their frame. What do all think???

 

i cant believe i didnt get any credit for talking you into this style of 4 link instead of what your were doing!.....sheeeeeesh what jerkie little *****!



looks good, box in the upper frame mounts, and i will give that pinion another look. the pics of the angle dont look so hot!

 

I'd suggest mounting a correct size wheel/tire on your axle now, to see where you are actually going to sit. There's a big difference in wheel size between a small fourteen wire setup and a wide whitewall setup.

These look to be the same car with both style wheels you talk about. Look at how much higher the center of the wheel is in the fender well when it has the wide whitewall setup.

 

Thanks for the images...so let me be clear:

The bottom fleetline has 15's with a c-notch?

The top has no notch and uses 14's? Let me know, thanks!

 

I don't know. I just posted the pics because it shows what a difference in size the two styles of wheels are.

I think that is the same car in both pics.

 

Looks pretty good so far man, but you stand a good chance to running into some problems by not having your trailing arms parallel to each other. If you can make them parallel and equal length you will not have any rotation of the axle causing pinion angle variation. Of course if you have limitiations created by the body, fuel tank, or other objects you don't have too many options. Might as well notch the frame while you are there. You can always limit your travel with some adjustable bump stops.

 

Looks good. Should work nice for you.

 

i dissagree, the point of a "triangulated 4-link (which he has) is to eliminate axle roll and side to side movement, thus eliminating the need for a panhard. i use only triangulated 4 links and love em! never any probs,...heres a pic of my last one 120+ miles an hours with airbags!

 

Looks great, but I do hope you really box the m ounts on the frame, just some triangular peices to distribute the force some.

 

I don't disagree with the triangulated 4 link setup. I think it is far better than the panhard bar setup. What I am talking about is the fact that the two trailing arms are not parallel to each other horizontally from the ground and the fact that the upper arms are shorter, are going to cause an arching motion.

 

he sayinf that either the upper bars need to be mounted higher at the frame, or the lower bars need to be mounted lower on the frame so that they are parallel

 

worked for gm like that for years.

 

Aeroman, I am watching in anticipation of redoing my rear set up (which is what you were attempting the first time). but as you know i am not totally happy with it and plan to redo.

I agree with above statement, ideally it should be a close to parallel as possible as it minimizes axle rotation but should still work Could you shorten your upper mount height to bring it down closer to the axle and making it alittle more parallel.

 

my 2 cents....When I did my coupe, I put the top front mounts where I thought they'd work. (similar to yours on the frame, not paralell to the bottom) I have a 10" notch on mine and the change in pinion angle was so bad that it would rotate down so much that the bags would rotate and had a real hard time inflating..Soo, I made new mounts for the top bars higher up so the tops were paralell to the bottom, and now there's hardly any pinion angle change and it sits lower...Just my experience....
Cody

 

yep, you got it....

 

cool man, i'll look into that...

 

oh, ok...so you made the mounts stick out from the top of the frame??? Maybe a pic would help...I appreciate the comments/feedback!!!!

 

Here is a pic from http://www.progressiveautomotive.com/triangul.htm

The angle of the pic isn't the greatest but note how the two trailing arms are parallel top to bottom. The upper arm is shorter probably due to clearance restraints. When you keep the arms parallel and try to get them close to the same length you get very little pinion change. It moves the axle in an arching motion but minimal pinion angle change. I have setup many long travel offroad trucks with triangulated 4 link setups that cycle a usuable 40 inches of travel. It is necessary to follow some geometry rules to do so. 40 inches or 4 inches you want quality motion. I am not familiar with your restraints on you car but you need to try and keep your lower arm parallel to the ground and move you upper arm mount up to create the same plane. If you have to notch the body a bit for that mount that is no big deal, just make a box out of sheet to cover it. Also you might as well notch the frame at this stage just in case you need more clearance. You can always limit that travel later. Better than getting done and not having enough travel.

I just looked at your pics again, and if you move your lower arms outboard and under the frame like in the pics from the above photo that would be a good start. you could shorten them a bit and attach them in the spot of your frame that starts to round up so you don't have frame to ground clearance issues. That would make the arms pretty close to equal length also. Then you would just have to raise you upper arm a bit it looks like to pull in that parallel.

 

actually gm's were closer to parallel through the arc of the suspension due to the fact that the upper links were at the very top of the frame and the lower links were mounted below the frame rail.

 

Well...I still don't see why the upper stock mounts couldn't be used and just position the upper frame mounts in the same position the ones are now...but on the needed angle to work with the cast upper axle bushing setup. The NEW upper mounts look to be exactly the same height!
Just an observation...not a complaint or anything!!!

Must say though, the new kit has a real look of quality about it. Not overly expensive either. Good call!

One thing that does make me wonder a little is your positioning of the links...

Are your lower links parallel to the road with the axle fully stuffed? Looks like it, but pics can be deceiving.
You should be positioning the links parallel to the road surface at RIDE height to prevent roll steer as the car leans in a turn. If the links head downward at ride height (Lower at the axle), the rear axle will be pushed rearward on the outside of the turn and pulled forward on the inside, thus causing a rear axle roll steer condition. The shorter the links, the worse the effect.
Makes for squirrelly handling.

Link positioning should be done at normal ride height and then cycled thru the full suspension movement range to check for clearance issues.
Poor angles when the frame is fully dropped isn't as big a deal as the car can't be driven like that for any length of time anyway.

 

sorry for the ****py pics..It's not done, the upper mounts still need to be boxed...

 

Hey Fellas, thanks again for all the feedback. The axle/rear end is tentatively sitting as if the car was laying absoulte low. Naturally, the bars would not be parallel to the ground.

What I first did was mount the 350 engine with the 700R4 ****** on the frame for my reference point. I then got the angle finder and obtained -4º down for the tail shaft of the transmission. I knew I wanted to get a pinion angle of -2º at ride height for a 4-link. I got the rear end posi and placed it under the frame until my "x" and "y" were achieved (i.e. 117" as my wheelbase and centered the axle).

Once this was done, I used my handy dandy angle finder to pivot the front yoke until I achieved +2º.

Without moving anything, I first tacked welded my lower bar brackets on the axle tube. I brought out the length of the bars (adjustable bars) 50% of the actual thread for fine tuning. Then, I tack welded the other end of the lower bars in the middle of the frame because I did not want to have the lower brackets prevent the frame from coming any lower on the ground.

Then, I tack welded the top bar brackets on the axle tube. I was ideally trying to get the upper bars to be 45º out from the axle tube to the side of the frame. But since space/fitting restricted, I went with my best case. I also gave myself about 50% of thread travel on the upper adjustable arms for fine tuning.

After this, I measured, measured, and then, measured again...with the axle all the way down, hitting the frame. Yes, I will end up doing a C-Notch on the frame (maybe a mild one). I expected the angle of the yoke to be off...that is why I will adjust to get to +2º on the face of the yoke.

The reason I didnt go with the stock trailing arms was because of fitting issues. If the upper and lower stock arms were fully extended to the frame, they would hit each other (interfere) on the side of the frame. If I kept the length of the stock trailing arms, I would have have to make a crossmember for it, coming right up under the rear seat. I never had an issue with the lower arms. The uppers were the ones giving me a headache. Here are some images from that work: