Help/Advice needed: Is my frame crooked? - Impala Tech
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post #1 of 12 (permalink) Old 07-29-2018, 01:33 AM Thread Starter
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Help/Advice needed: Is my frame crooked?

This will sound a bit odd, but, in the past week or 2 I am beginning to think that maybe the front of my frame is tweaked.
I don't know why this hasn't shown up for me in the past 5-7 years but well, it became obvious recently after a trip to a local shop for front coil-spring cut, and alignment and 2 new tires.

It looked good when I picked it up, then it poured rain and I noticed a short rough-riding trip home. Rougher than expected - I've been in lowered cars before and this was stiffer to me.
Later, I found the drivers side control arm sitting on the 50yr old bumper-stop and the passenger side control arm bumper-stop was more deteriorated and broke in half. whoops.
It was obvious at that point that the passenger side fender-lip was sitting about 2" lower than the drivers side. dammitdammitdammit.


Since I've never noticed this before when it had original springs, and also not noticed for the past 2 years on the Global West springs that were 4-5 inches too high, I was expecting that the local shop may have cut the springs differently.
I took things apart, found the cut springs were identical but thought it was odd that the LCA adjustment on both had the bolt at the upper-right corner. (since this pulls the LCA in/out, technically, it alters the spring angle and to some extent I wouuld think it's mechanical length and effectiveness) So, the passenger LCA was pushed out as far as it could go and the Drivers LCA was pulled in as far as it could go. I decided to put them both to the middle to even things out and adjust the top of the UCA to get desired Camber.


I was hoping that might have been all it was but I still have a bit of a lean on the passenger side, but I think the LCA adjustment did help a little.
I started looking closer and I'm starting to believe my frame is tweaked and I may have to take it to a collision shop to be checked.

What do you guys think?

https://tinyurl.com/yadd788o
(That link is https so your browser will give the usual warning)
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Last edited by BA.; 07-29-2018 at 11:41 AM.
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post #2 of 12 (permalink) Old 07-29-2018, 10:07 AM
 
 
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I would think its your springs. between your comments on ride quality and not having noticed it for years, I doubt it just went "crooked" unless it has some severe rot somewhere and it is starting to collapse. I doubt that the cam position on the adjustment bolt would change suspension geometry enough to cause those symptoms and asymmetry.

from what I have heard, cutting springs is not a great idea because it changes the spring behavior and "spring constant" which may explain the harsh ride. another "budget" lowering technique would be to heat them up, which would possible cause a lot of what you are seeing.

Before you take it anywhere, try this: put the frame up on jack stands, all equal height, so that all wheels are off the ground. then measure the distance from the frame to floor (assuming your floor is level). check all four corners. right and left side should be equal. if not - most likely its a frame issue. if putting it on jack stands levels out the appearance, and right side = left side heights, then you have ruled out the frame and ruled in the suspension.

side note: it doesn't have to be front springs either. check your rears - maybe one is broke.
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post #3 of 12 (permalink) Old 07-29-2018, 11:27 AM Thread Starter
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Thanks Milo..
I'll double check the rear springs and try some more measurements.
No question that cutting coils increases spring rate and decreases ride quality.
My 4 mile drive home was extra harsh though. Essentially no bump suspension. because I was riding on the bump stops.

In my link above there are two vertical green lines that are to two spots on the front frame. (L/R) They're off.
To me even the space between the LCA and the Lift is different from left to right.


After sleeping on it last night, I was recalling one particular bump that made me say "oh s***!"
I'm wondering if that one bump and this busted,ultra deteriorated bumper stop led to the tweaking.
Tweaking, not twerking.



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Last edited by BA.; 07-29-2018 at 11:53 AM.
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post #4 of 12 (permalink) Old 07-29-2018, 01:18 PM
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I was never a fan of those washers to adjust camber on a front end. Chevy used them because they were cheap.

Further; back in the fifties and sixties you could tell it was spring, not by the Robin returning, but seeing all of the low paid, low skill city workers out patching pot holes. Those guys retired to a life of luxury living off of social security (I'm being sarcastic here: for those who are not old enough to remember prison road gangs, or to collect a social security check), and took their low wage job with them because no one wants to pay taxes to pay for services.When these cars were new the roads were maintained. Not so much today. So with a washer holding your front end alignment by force of friction. You are one pot hole away from knocking your alignment all out of wack.

If you depend upon avoiding pot holes to align your car then you need this handy tool that costs one fourth the cost of a Bear Laser alignment, and you can do it your self in minutes.

https://www.walmart.com/ip/Adjustabl...&wl13=&veh=sem

As to frame dimensions the Fisher Body service manual has all of the specs you need to check for distortion with a tape measure. Additionally the Chassis Service manual has the specs to align the front end using nothing but a tape measure (you don't think they stopped the production line to put the car on an alignment rack when they were building them back in 1964 do you). This only works with a straight frame and all new front end parts as any wear will throw it off (but you can use the specs to get you to an alignment shop if you just rebuilt your front end with all new parts).

Bump stops are an important part of your cars suspension. They are there to keep from bending A-arms or lower control struts. A bump stop is a variable rate spring suspension part that is to used in an emergency only if your suspension unexpectedly compresses completely (like you just fell into a tank trap while cruising your city streets). If you lower your car you will be hitting them more frequently which is why I use stock height springs and lower by using a raised spindle on the steering knuckle to lower my center of gravity for road racing. The after market sells shorter but stiffer plastic bump stops to replace the rubber ones on a lowered car (they also sell plastic ones for stock ride height bump stops that have a different shape). It is the shape that provides for the variable spring rate so never lop off the top for clearance as that defeats the purpose of the bump stop.

Big Dave
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post #5 of 12 (permalink) Old 07-29-2018, 02:03 PM Thread Starter
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So so mad and bummed right now.
The LCA is definitely bent and I think this forward piece that attaches to the strut rod is also tweaked by looking at a straight edge on it.

Pictures are L/R comparisons of LCA bottom, and the strut arm frame-mount and the sway-bar end natural resting position at LCA right now. Sway bar is Addco 1 1/8". it's all out of whack on that passenger side.

I'm postulating whether I can use a come- along and pull the front strut arm mount back into position. (With the strut arm unbolted)
I can buy a replacement LCA.




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post #6 of 12 (permalink) Old 07-29-2018, 02:16 PM Thread Starter
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It's hard to swallow spending $700 on lca's.
Can I trust the quality of these?

https://www.classicindustries.com/sh...-control-arms/



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post #7 of 12 (permalink) Old 07-29-2018, 04:20 PM
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Just like to point out
Quote:
Note: Imported.
, as in if the price hasn't already jumped 25% already because these parts are made out of steel it will soon. And to add to that a second or two later expect a 50% increase in price because of where they are imported from!

Any fabrication shop could make a set out of imported steel (hopefully imported from Sweden or Germany as the Chinese steel is of *is* poor quality). Basic tube stock and flat sheet parts bent to shape and welded together then powder coated. The red plastic spring pad is available from Energy Suspension made out of Mil Spec polyurethane in the US.

I used to frequent fabrication shops and machine shops run by a tool and die makers back in the nineties when I was still working as an engineer to get things prototyped for testing. I had dies made and fixtures made that were much more complex than this for under $500, but times change.

Big Dave
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post #8 of 12 (permalink) Old 07-29-2018, 08:25 PM
 
 
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Quote:
Originally Posted by BA. View Post
So so mad and bummed right now.
The LCA is definitely bent and I think this forward piece that attaches to the strut rod is also tweaked by looking at a straight edge on it.

Pictures are L/R comparisons of LCA bottom, and the strut arm frame-mount and the sway-bar end natural resting position at LCA right now. Sway bar is Addco 1 1/8". it's all out of whack on that passenger side.

I'm postulating whether I can use a come- along and pull the front strut arm mount back into position. (With the strut arm unbolted)
I can buy a replacement LCA.


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that sucks that you hit a bump that hard and it did all that. I know those LCAs are weak but, wow. I am no suspension expert but I would say that something is wrong with your set up. shocks are supposed to absorb the impact, not your bumpers, not your LCA, not your sway bar. so you should probably figure out what went wrong before you start dumping money into new parts. if you lowered your car, you should probably invest in stiffer shocks that are designed for the shorter travel.

this is all assuming something did not come into direct contact with the LCA - but you would see signs of impact and I am sure you would have seen that in the road...

to bad you are not closer to me, I have an extra set of LCAs from a 66. I am sure most anything aftermarket is better than original, but you get what you pay for there, as well.
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post #9 of 12 (permalink) Old 07-29-2018, 08:55 PM Thread Starter
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Quote:
Originally Posted by mferraro76 View Post
. ...so you should probably figure out what went wrong before you start dumping money into new parts.....
.
I'd say we're 100% sure that we know what caused it.
4000lb car at 40mph, zero suspension compression available because the springs were just a bit too short + some kind of pothole or bump that I couldn't see in the rain.
Newtons 2nd law of physics:
The net*force*on an object is equal to the mass of the object multiplied by the acceleration of the object.
With no suspension compression, all the force gets transferred to the UCA and LCA and now we know where my two weakest spots are at.

It doesn't help that the stock LCA bump stops are mounted on the frame in a position that stops movement a little bit too early for a lowered car.

Too bad I didn't know all that when I picked the car up.


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post #10 of 12 (permalink) Old 07-29-2018, 09:12 PM
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Shocks do not stop compression or rebound; they dampen the oscillations between the end points so that you maintain control of the wheel and tire. Without shocks the tire will dribble itself down the road spending more time in the air than in contact with the pavement. Springs and shocks require eight inches of travel normally. If you do not mind the car riding like a lumber wagon (what suspension) you can get by with a minimum of six inches. But it will take an ultra duty shock to control the extremely stiff spring rate. Car should not normally encounter a bump stop in it's normal travel. They are there to prevent bending parts when the suspension bottoms out.

I used to road race Camaro and Nova cars. I would substitute the stock 270 inch pound springs for 420 to 500 pound spring rates (depending upon how fast the track was) and I had Bilstein shocks that where not only adjustable but modular (the way a Holley carb is using a selection of standard parts) making them easily rebuildable between races with a wide selection of valves and nitrogen loading. I depended on the Bilstein race rep to charge my shocks and to ride with me to make recommendations as to what he though I was doing wrong (as opposed to what I actually got right; as I was still learning).

Big Dave
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post #11 of 12 (permalink) Old 07-30-2018, 07:44 AM
 
 
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Quote:
Originally Posted by BA. View Post
I'd say we're 100% sure that we know what caused it.
4000lb car at 40mph, zero suspension compression available because the springs were just a bit too short + some kind of pothole or bump that I couldn't see in the rain.
Newtons 2nd law of physics:
The net*force*on an object is equal to the mass of the object multiplied by the acceleration of the object.
With no suspension compression, all the force gets transferred to the UCA and LCA and now we know where my two weakest spots are at.
I totally agree. springs are not going to slow compression by any significant amount, they are mainly to return the vehicle to ride height and help with load. shocks will not "absorb" or dampen anything if there is zero inches of travel. but I have seen plenty of vehicles on drop springs ride around all day on roads with potholes and not have bent control arms, sway bars, etc. they usually have bent rims but that is another story. they make shocks, as Big Dave pointed out, for lowered applications due to the shorter travel so that when newton's 2nd law kicks in, the shock takes some of that force and converts it into pressure (a little rusty on my fluid dynamics so no formula for that) instead of sending it straight to the control arms, frame, etc. +1 for the drop spindles to prevent this from happening again.

BTW, what is up with the shop you took it to? didn't they see everything resting on the bump stops when they put it back together?
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post #12 of 12 (permalink) Old 07-30-2018, 12:31 PM Thread Starter
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I'm a fan of the drop spindle too and they ARE in my master plan however I was going to do them with a disc brake conversion. $$
I thought some cut coil springs would be a workable temporary plan.


And you're right, the local shop didn't notice the car sitting on the bump stops. .

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