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Front suspension question.

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08LTZ

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I have a 72' K5 that I am working on. I have had many other vehicles with front leaf springs and shackles. I have never had any with the brackets that are mounted to the frame just behind the rear shackle. When the vehicle is on the ground, the leaf spring rests on the bracket. The drivers side one is there but the other side is missing. What is the purpose of these? It looks to me that they are there to limit the swing of the shackle. I have is up in jackstands and on the side where the bracket is missing, the rear of my leaf spring hits my header flange but on the side with the bracket it does not. Is what I am looking at correct? If so, does anyone have a spare they would like to get rid of? I really don't feel like buying new headers and exhaust right now. Thanks
 
I don't know why you'd wanna limit the amount of movement in the shackle and I'm pretty dang sure I don't have anything like that on my rig. A picture would really help.
 
 
I am pretty sure these are factory because they are shown in diagrams I have seen in the LMC catalogs0.

IMG_6370.JPG

IMG_6371.JPG
 
You're right. I see them in the LMC catalog picture with the leaf spring assembly. But no name or part number. Like I said before, I'm not sure why you'd wanna limit the movement of the shackle. Less movement of the shackle means less travel in the suspension and less flex in your springs. Most guys around here are trying to get all the travel they can. Judging by the arch in your spring, you have at least a 4" lift. How much travel are those things giving you?? I'm not sure what to recommend, other than find another one, or take the one off. I will say that I wouldn't run it with just one.
 
Yeah my truck had the one on the drivers side too. I still can't figure out why they put those there, but after looking into it, everyone junks it. I remember reading about one guy who hit the brakes pretty hard and that bracket ended up making things interesting. Toss it.
 
mr_blasto said:
I remember reading about one guy who hit the brakes pretty hard and that bracket ended up making things interesting....
Click to expand...


Hey, I'm "that guy" you remember reading about. :D



OK, time for a 1st Gen history lesson. Pull up your chairs and gather around:


When the Blazer first came out, there were concerns about accidents being caused by broken leaf spring bolts. I am not sure if there were actual reported cases in the 1969 model year, but Chevrolet did two things to change their initial design of the K5 front suspension. (I believe this was also a dealer "retrofit" for earlier trucks too)

1. Weld on a metal strap across the front of the driver's side front leaf spring hanger to create more of a "cage" to retain the spring if the front leafspring bolt snapped.

2. Add a small metal "fin" behind the driver's side shackle to prevent excessive movement of the leafspring if the rear leafspring bolt snapped.

The reason this was done only on the driver's side is because a bolt failure on this side of the truck would have a large, detrimental effect on the steering of the truck, since the stock draglink and steering setup pushes on the driver's side knuckle.



When I added softer (and longer) front leaf springs to my truck, I quickly found out that the rear "fin" prevented the spring from moving backwards as it compressed. This was VERY noticeable on hard braking.... here's why:

Under braking, both springs are compressed and the shackles swing backward to allow the spring to "grow" in length. When the driver's side leafspring hits that stopper (aka "fin") it stops flattening out....but the passenger side does not. As the passenger side continues to compress and flatten out, the axle also shifts backwards (albeit slightly) along with the shackle. This translates to the truck steering itelf to the RIGHT, even without any steering input from the driver. At highway speeds this is MUCH more pronounced and quite terrifying.

So, the short answer to your inquiry is that the leaf spring should NOT be hitting that "fin" except in the event that your bolt has broken. If it is, you are probably getting strange steering effects. The easy solution is to remove it completely. A more "cool" solution is to redrill the holes and move it back slightly so that it doesn't interfere with normal driving (or wheeling). It's a neat little piece of 1st Gen Blazer history that would be fun to preserve if you can....call it a "conversation piece" for next time you hang out with the later-model Blazer guys. :wink1:

Another bit of trivia: If your bracket is like mine, when you take the mounting hardware off and polish it up you'll find that those nuts are actually made of COPPER, not steel. Pretty cool!


:usaflag:
 
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Thanks, yep my driver's side front spring had the piece of metal to cage it also. I thought it was just another rig job the previous owner did?:doah:

so if things went bad the factory figured they would rather have you go off the road to the right instead of into oncoming traffic.
 
The weight of the truck helps hold the spring underneath the framerail pretty well if the bolts were to break.

However, if you were to crank the wheel at the same time, either end of that spring could slip-out from underneath the frame. If the bolts broke as a result of a panic stop...my guess is that the axle would have headed completely underneath the truck until it hit the rear axle. No matter what, it wouldn't have been pretty.

:usaflag:
 
I remember this too, there was a recal letter sent out for that spring eyebolt breaking. Anyone remember that old first gen site called blazer-net.com? anyway someone on that site had the letter in their glovebox and scaned it for all of us to read. I kick myself for not making a copy of that jpg file :doah:
I just removed the "fin" and left the strap there...oh and grade 8 eyebolts :D
 
Greg72 said:
Hey, I'm "that guy" you remember reading about. :D
Click to expand...


I had a pretty good idea that it was either you or Burt, just didn't want to be inaccurate. No disrespect meant by referring to you simply as "some guy." Some of my best stories involve "some guy." Seriously, thanks for the history lesson.
 
Now I really want to find that original recall letter:

I remember the Blazerholics or Blazer-Net sites too.... back then, you could only find a couple of sites about early Blazers, and there was almost NO tech available.

There are sites that specialize in archiving old web pages from the internet. I've done a little digging and have found some old references to Blazer-Net and Blazerholic but no specific info on that recall letter.

It's out there somewhere.....hiding like a tiny criminal.



:usaflag:
 
But Greg, most first gens, including mine, had front springs that have a negative arch from the factory. When you hit a bump or brakes don't these arch upward further and pull the rear shackle forward in the process (not backward). Just a question, not being smart or anything.
 
gaspass said:
But Greg, most first gens, including mine, had front springs that have a negative arch from the factory. When you hit a bump or brakes don't these arch upward further and pull the rear shackle forward in the process (not backward). Just a question, not being smart or anything.
Click to expand...

Now that I think about it, on compression a flat spring would cause the shackle to swing forward and away from the fin.

I hate to admit it now...but I was under my truck today and saw that I had "the fin" still on mine. Not entirely sure how I missed it before, but I took it off. I'll probably put it back on again later and push it back and inch or two so's the shackle won't hit it.
 
I read all the posts in this thread and no one seems to notice the header flages in the background. If you take that "fin" off you better check to see if the shackle bolt will clear the flange or your gonna hate it when your replacing your headers.
 
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