55.2-59 Opinions on crooked bed?

[72 k15]

Needing some opinions on if the bed mounts maybe are gone or if worst case the frame is bent? But on the 59 it doesn’t look like they had rubber mounts?

[mr48chev]

Too much of a part off my job as a front end man and algnment specialist in the 70's was leveling customers cars that were a bit off from level.

Step 1 make sure you have equal pressure in all 4 tires.

At the same time make sure that the two front tires are the same size and height and that both rear tires are the same size and height.

Park the truck on a floor that is perfectly level.

Measure from the floor to the frame rail on each corner.

On the rear measure from the axle to the frame on both sides.

Being as the box lines exactly match the bumper I'm thinking you have suspension or frame issues.

I don't think it is the case in that truck as just that corner is low but on my 48 the whole left side is lower than the right because 80 % of the miles on it were with just me in the truck.

[72 k15]

I will try that, front tires are the same to each other the rear are the same to each other. I will do some measuring when I get home, but I do know the bumper is custom made. And could be messed up. And honestly the picture makes it look worse then it is.

[72 k15]

I got some incollusive info I’ll have to drive it somewhere better or get a flat level or maybe take it to a frame shop, how much would a adjustment cost?

[mr48chev]

The bumper came from a regional vendor who sold step bumpers to dealers in the region that that truck was sold new.
Custom in that each manufacture of the bumpers did a few things to make them distinctive as being their bumpers.

Other than that tiddbit you can seen that the talgate and bumpr are exactly parallel. Tt means that the bed hasn't settled down on the frame any at all.

[dsraven]

like mr48 says and then check all the springs for a broken leaf and maybe the number of leaves in each to ensure the fronts are the same and the rears are the same. a weak spring can cause the sag and it may not be a rear spring necessarily. a weak front spring on, say, the left front can cause the right rear to be jacked up. get the dimension from the axle to the frame on both sides on the front and compare, they should be close. then do the same for the rear. go under the truck and look for any physical damage. you can do the frame checking as per the assmebly manual as well. more involved though and kinda hard with the truck body on. the other thing it may possibly be is a shock absorber that is sticking. you could try removing a shock bolt, one corner at a time, and see if any of the shocks are holding the suspension from relaxing at rest. have you tried greasing the spring pins? if so, did they all take grease easily and squirt grease out at both ends of the pin? if not possibly a sticky spring pin is causing the suspension to bind. these trucks were meant to be greased lots so it is a good idea to find all the grease points, grease them and ensure they take grease fully and not just squirt a bit of grease out one side of the pivot point. I usually grease stuff until I have fresh grease exiting the joint then clean off the excess. when done mark each grease point with a paint marker so you can find them all next time. count them and mark it down somewhere under the truck so you can remember.
55-59 chevrolt truck factory assembly manual can be downloaded for free at the tri5 site. just google it. lots of good info in there.

[dsraven]

the pad to park the truck on doesn't have to be level fore to aft, just side to side.
have you tried jumping up and down a few times in the truck box or on the bumper to see if the springs allow the truck to move the same on each side? if not check the shocks. simply unbolt one end of the shocks and pry them out of the brackets so they are free from the axle, then jump up and down a few times in the truck box or on the bumper to bounce the suspension a few times, then let it settle and see if the truck box still looks sagged. do the front as well. if a shock is holding things up you can usually tell when the bolt comes out because there will have been some pressure on the bolt and the truck may move a bit once the bolt is out.
on the springs, look for a cracked leaf or an actual break where there is a leaf in the pack that is partially missing or has seperated from the rest of that leaf. sometimes these craks can be noticed because there is a powdery rusty colored area near the crack.
sometimes over the years these old trucks get fixed as economically as possible. maybe the truck had a spring repair where the guy only did one side at the rear of front. or maybe a spring from another truck was installed on one side, rather than buying a new spring, because the guy happened to have one or got one from a wrecker or donor truck. either way the springs were then not matched and one may have sagged more than the other over time.

[72 k15]

When I first got the truck I greased all the pins until grease escaped. The shocks do look old that could be a possibility. When measuring from the axle do you mean just the top of the axle to the bottom of the frame rail? I will check springs and report my findings, The truck still drives well.

[mr48chev]

Yes, top of axle to bottom of frame. What you are trying to do is figure out where and how it is out of kilter.

Bassically looking and measuring until you figure out what the issue is and how and if you want to deal with it.

[72 k15]

Right rear shock is 20.25” the left rear shock is 19.75” frame to axle is within 1/4” on both sides. Across the frame in the rear is 49” and 49.25”
I talked to a chassis olace local to me that would be willing to do the frame if it is bent. They said worst case 800 which is not to bad. They said it’s probably the shocks or leafs.
I put a picture of level buble from the frame rails they are exactly the same in the back that little movement in the bobble is probably the driveway slope.

[dsraven]

Get a level on the pad the truck is sitting on, side to side,then clean a spot on the axle tube, place a torpedo level on the clean spot. Those angles should be the same unless there is a tire or wheel height issue. Then check the frame side to side and see if it is the same. A digital level is good for that because it says the actual number instead of showing a bubble in a glass tube which depends on the angle you look at it by.
Maybe sagged springs?

[72 k15]

Supposed to be nice out tomorrow I will go to a flat parking lot and get all the levels

[dsraven]

check all tires to ensure the fronts are the same size and the rears are the same size, should be the same size on each axle, and inflate each the same psi
disconnect the shocks from one end of their mounting to eliminate them from the picture
hypothetically now,
pad is sitting at zero deg, truck gets rolled onto the pad and wheels blocked so it is not held by the brakes or the transmission/engine
check
rear axle is also sitting at zero deg measured on the axle tube
frame is not sitting at zero deg
problem noted
then
check midframe to see what angle that section of frame is sitting at, front of box area roughly
check tthe frame behind the rear axle and compare to the other rear frame notes. if the section behind the axle is not the same as the section ahead of the rear axle then maybe you have a bent frame. sometimes this can happen if somebody dropped a heavy load in the rear section of the box at some tie in the trucks life. more parts to check before a conclusion can be had
check front axle to see if it is sitting at zero deg
check front frame to see if it is sitting at zero deg
compare notes

that should give you an idea of where the fault lies. maybe just a sagged spring on the front or the rear or a siezed or problem shock absorber, spring pin etc
post up your results if the answer is not obvious to you

check the frame drawing pics from the assembly manual and you will see that the frame is pretty much straight except for the bump over the rear axle and the downward slope at the front. if possible run a stringline under the frame rails, fore to aft and see if there is a sag somewhere. use a block of wood or something as a spacer under the string at both ends so the string is off the frame by a little bit, then use a third block of the same size to go along the frame length,the block between the string and the frame, to see if the frame wavers from the string at some point.

[72 k15]

Front tire sizes are the same and at the same pressure, Same with the rear,Should I lossen all 4 shocks or just the rear 2?

[dsraven]

I would do all shocks, take one end off it's mounts for each one to eliminate that as a source. Then bounce the truck and stand back for a look, maybe that is the fix.

[mr48chev]

I've seldom seen a shock bind up enough to cause that issue unless the rod was bent.

All too many guys do overtighten shock bolts or nuts squishing the bushings and maybe causing the bushing to bind.

What you are looking for is what is different between this side and that side.

Axle to frame difference between one side in the other or shock stud to shock stud difference between sides Springs or ? If ther is a half inch here, does that multiply to the difference I see there?

I had to deal with very spoiled repeat customers at a Pontiac dealership in the 70's. No customer issue got sluffed off at that dealership and even the most minor issue with a new car was addressed. Minor meaning that some would come in and show you that this fender lip sat 1/4 of an inch lower than that fender lip. We fixed it.

Step one for me was always checking and adjusting tire pressure. That was the early days of factory installed radial tires and all too many customers came in with as much as 70 lbs of air in a tire because they didn't like the look of the radial tire sidewall at the designated tire pressure. Quite often tire pressure would vary as much as 15 lbs. quite often they came back in with their week old Pontiac Grandville and complained about the rough ride and when I checked the air pressure and set it back were it belonged by specifications they fussed that the tires looked flat.

Any how make sure that tire pressure is correct and matched on each front and rear pair of tires. That sounds like nonsense but I have seen nearly new tires where one side had a 215 and the other had a 225 before.

Then get out your tape measure or yard stick and measure at several spots around the truck while it is on that level surface and you have given it the John Lamb bumper bounce on both ends. Measure at matching spots on each side front to rear on both sides and make yourself a diagram of the measurements on a sheet of paper.

THEN look at your measurements and figure out how it is off.
The left rear is low, that is rather obvious, but is the right front a tad high?

Is the right front just a bit higher than the left front?

Now back to those under the truck measurements. WHERE IS IT DIFFERENT SIDE TO SIDE AND CORNER TO CORNER?

Next step DO NOT LISTEN TO THE BS ARTISTS. I am sorry but some of these guys guess at things to sound knowledgable and dsraven, myself, Joedoe and a couple of others have to work overtime at setting things right.

After you have your outside body measurments and the frame to Axle measurements on all four corners you should be able to figure out if the issue is tweaked frame or worn out or damaged suspension.

That means look at the leaves on all four corners and see if there is anything broken or if there is anything different between sides such as 10 leaves in one side and 11 in the other. Does the arc of the spring match side to side with no load in the truck?

Then down to the nitty gritty. when you look at the ends of the springs and the shackles do any of them look like you have a bushing that is way more worn than on the other side. Does the front end of the left rear spring look like it is setting up in the spring hanger more than on the right side. are the rear shackles at exactly the same angle side to side.

It looks like the left rear is a half inch lower than the right rear at the axle, now figure out why.

Bad thing is it may be caused by something that you don't know about such as a previous owner carrying something quite heavy on the left rear side all the time for a long time.

Make sure that the tires on each axle are the same brand and size.

[72 k15]

Pulled the shocks off and jumped on it still crooked.

Drivers shock mount 19” passenger 19.5”
Drivers frame to axle 6 1/8”maybe little over ,pass 6 1/8” maybe little under difference of about 1/32”

Drivers wheel lip rear 26 15/16”
Pass wheellip rear 27 1/8”

driver rear bumper 16 15/16”
Pass rear bumper 17 5/16”

[mr48chev]

OK that proved that the nonsense about the shocks was just that, NONSENSE from a wild guess. People who don't know anything repeat what they heard from the spit and whittle club rather than offering known solutions.

I know I am stomping on toes here but by gum if you don't actually know what you are talking about quit throwing out wild guesses to people. It seems to be the same repeat offenders every time.

[72 k15]

Based on those measurements I am thinking it might be a sagged leaf spring?

[1project2many]

It may be partly due to sagging springs. You listed about 1/2" difference in height between L and R sides at the shocks but 1" difference at the rear of the wheel well?

Tires of same size doesn't mean same diameter tires. While you're taking measurements do yourself a favor and check that both rear tires are the same height. The absolute best way to do this is to compare rolling circumference. Tires 1" different in height show a 4" difference in rolling circumference so its pretty obvious. And this method will catch stuff like the tire being highly crowned or a tire having a bulge in the tread.

Park the truck in a spot where it can freely travel the distance of one tire rotation, generally between 6 and 8 feet. Use chalk or crayon to draw a reference line down the sidewall of each rear tire at the 6:00 position and continue onto the ground. Then roll or drive the truck straight ahead or straight back so one tire makes a complete revolution. At this point looking at the reference line on the other tire is enough to indicate a difference. If both both reference marks are not touching the ground you have a difference in tire height. There is a way to calculate the actual tire diameter from this using easy math if you're curious.

I know I am stomping on toes here but by gum if you don't actually know what you are talking about quit throwing out wild guesses to people.

Call the local observatory and see if there are any comets above your house. Comet gravity does weird things to fleet side trucks.

[mr48chev]

Truth is if you were to park 50 old pickups that had not had lot of recent attention on a level parkng lot in a row and stand back and look 40 of them would most likely be off kilter a bit.

That could be for any reason you can think of including always being on the road with just the rather heavy driver in the cab. hauling too heavy of a load all too often, hauling a heavy fixed load like an air compresser or welder on one side of the bed, Parked on the same spot of uneven ground on a regular basis. Then we get to worn out or damaged parts.

[G&R's57GMC]

Enough !
Put the truck on level ground , get it up on 4 equal jack stands at the chassis straight rails ahead of the rear suspension mount and behind the front suspension mount .

Take a long level across the frame rails at these points , then across the rear frame rails and the rear bumper .

If the frame is bent this should give you a good idea where .

This method takes the suspension and tires out of the picture .

Good luck .

[dsraven]

haha, I'm with you G&R, get'er done.
my advice, don't think too much into it and spend too much time reseraching instead of getting hands on and getting to the nitty gritty. it's probably a leaf spring issue unless there is obvious damage from a previous accident etc.if the tires are all inflated the correct pressure and are the same size on the same axle, the shocks have been released, there is no obvious problem with a spring hanger, and it is still low on one side, then it is prolly the springs that are sagged for whatever reason. aside from pulling the body off and doing some real dimensional checks on the frame only, you gotta go with your gut. buying new springs and doing the spring hanger pins and bushings isn't gonna break the bank compared to getting the frame checked etc, if you can do the work yourself. so, if you do the springs and hanger bushings and you fnd out the frame is tweaked, have you lost anything? nope, it prolly needed the springs and hanger bushings anyway. unless you plan to get rid of the truck. the only thing I would say is don't do the front springs if you plan on an upgrade to IFS, just do the IFS now and the associated brake upgrade to a dual system master cylinder. or, keep driving as is because the little sag isn't the end of the world anyway. save up and do what you want when you have your honey pot full. it's running, its driving, its all good. get a plan on what you want from the truck and stick to it. if you want an original driver and the sag really upsets you then continue checking until you find the cause. if you plan to upgrade a bunch of stuff then start saving and do stuff as you can afford it. get a plan and stick to it, don't go down the slippery slope of "well, I have it apart so I might as well redo this or that". it is important to have a plan, stick to it, and soon you will have your dream truck.

[duramax55]

mayybe check the low side leaf to see if you can find a broken, cracked leaf on the spring.Just a thought

[mr48chev]

Originally Posted by G&R's57GMC

Enough !
Put the truck on level ground , get it up on 4 equal jack stands at the chassis straight rails ahead of the rear suspension mount and behind the front suspension mount .

Take a long level across the frame rails at these points , then across the rear frame rails and the rear bumper .

If the frame is bent this should give you a good idea where .

This method takes the suspension and tires out of the picture .

Good luck .

This will tell you if it is frame or suspension.

You want your stands under the straight bottom of the frame placed close to the spring hangers front and rear so you can tell if the back end of the frame is tweaked.