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73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Topic started by: MrFiveOh on December 01, 2017, 05:44:03 pm

Title: Measuring suspensions points to locate where lean is coming from.
Post by: MrFiveOh on December 01, 2017, 05:44:03 pm
So like the title says, what information do we have in regards to locating what the suspected reason a vehicle is sagging or leaning to either side. I have seen on other pages and this one to measure from wheel opening to floor, floor to frame and bushing to floor and it will give you an idea of what is wrong but it doesnt go into detail any further.

For example my truck is a 74 SWB with passenger side 16 gallon gas tank. lowered 5/6 with new coils/spindles and flip kit in the rear (no bump stop). but is a  half inch difference (passenger side lower) from both sides and my rear passenger side is 1/4 lower than driver side.

Front Driver side from floor to bottom of fender is 28 1/8
Front Passenger side                                           27 5/8
Rear Driver side                                                  27 7/8
Rear Passenger                                                   27 5/8

very back of rear frame near bumper is half inch difference from driver side and passenger side.

So what gives? Am i supposed to be looking at cab bushings? leaf springs?

Everyone says "thats just the chevy lean" well i say eff that theres a way to make the disparity less and based on measurements where do i look. The chevy lean is common in trucks that had the gas tanks on the same side as the driver, not the case on this instance. plus a 16 gallon tank only weighs 110lbs at most. So that didnt cause the disparity because i weigh 180 and i dont even move the driver side of the truck more than a 1/8 when im in it.
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: AZ4X4SQBDY on December 02, 2017, 07:53:11 am
1/4" from the bottom of the fenders and a 1/2" really isn't that much, there is that much adjustment in the bumpers by just loosening them and repositioning the brackets. You could also slip some shims under the cab mounts to raise it up a bit.
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: MrFiveOh on December 02, 2017, 08:25:45 am
1/4" from the bottom of the fenders and a 1/2" really isn't that much, there is that much adjustment in the bumpers by just loosening them and repositioning the brackets. You could also slip some shims under the cab mounts to raise it up a bit.

1/2 and in doesn't seem that bad, for for some reason it's very clear in the front.
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: VileZambonie on December 02, 2017, 02:21:32 pm
Does it lean worse with weight in the bed?
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: SkinnyG on December 02, 2017, 03:23:09 pm
I disassembled my leaf pack and re-arced them so they were the same side-to-side.  Almost all the leaves (I think it is an 8-leaf pack on mine, I could be wrong) were inconsistent.
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: MrFiveOh on December 02, 2017, 05:57:11 pm
Does it lean worse with weight in the bed?

I don't carry much of anything in my bed except a dog or two. It's not a hauler, I have other vehicles for that.
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: VileZambonie on December 03, 2017, 07:44:26 am
The easiest way to tell if you have a fatigued spring pack is to place a load in the bed. The weak side will layout at a more progressive rate when you add weight centered at the rear of the bed.

You should equalize tire pressures and on level ground measure the distance from the center of the spring pack to the frame. If you jack up the low side enough to equalize the measurement and the body levels out then it's probably fatigued springs causing the lean. Do the same at the front from the edge of the spring pocket to control arm. Check for rot, body mounts, collision damage. The measurement points on the frame are in the service manual too.
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: MrFiveOh on December 03, 2017, 10:59:26 pm
The easiest way to tell if you have a fatigued spring pack is to place a load in the bed. The weak side will layout at a more progressive rate when you add weight centered at the rear of the bed.

You should equalize tire pressures and on level ground measure the distance from the center of the spring pack to the frame. If you jack up the low side enough to equalize the measurement and the body levels out then it's probably fatigued springs causing the lean. Do the same at the front from the edge of the spring pocket to control arm. Check for rot, body mounts, collision damage. The measurement points on the frame are in the service manual too.


Pressure is all the same and i measured in my garage so the measurments were taken when level. I did lift the passenger side at the frame and i was able to level out the truck that way. The front springs are brand new, so are you saying i should swap the front coils to see if one is weaker than the other?) Is there a sticky that has the service manual you are referring to?
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: Captkaos on December 04, 2017, 12:08:11 pm
The measurements you are giving are small like 1/2".  There is no such thing as Chevy Lean.  ALL springs settle and they don't settle the same.  you could move them and make it worse.  Pick any new car/truck randomly and measure them you will find the same thing...

The manuals are located here:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=30115.0
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: MrFiveOh on December 04, 2017, 12:28:46 pm
Capt, I get an error when i click on that link...... "The topic or board you are looking for appears to be either missing or off limits to you."
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: Captkaos on December 04, 2017, 12:43:33 pm
fixed it
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: VileZambonie on December 04, 2017, 02:29:17 pm
Quote
The front springs are brand new, so are you saying i should swap the front coils to see if one is weaker than the other?

No that wasn't what I was saying at all.
Title: Re: Measuring suspensions points to locate where lean is coming from.
Post by: SkinnyG on December 05, 2017, 10:10:10 am
There is no such thing as Chevy Lean.

My previous truck was a lowrider Nissan Hardbody.  On the Hardbody forums, they all talk about the "Nissan Lean."  I concur with the Captain - It's just spring age.

They are not hard to re-arc into shape with a hydraulic press and a large piece of channel iron.  It can be done with a hammer and something solid, like an old engine block.

(http://gwellwood.com/wordpress/wp-content/uploads/2013/06/IMG_20151127_173300665.jpg)