Boppa's old yeller truck

[Low Elco]

I'm with you. Boppa said last night that the big vibe was what started him doing the brakes, and it's gone downhill from there. As far as the axle, He (Vic) and I have been in collaboration. I completely swapped rearends in the process, no soap. I have another couple of plans in the works, we'll see how it goes.

[Xeen]

Its also possible you have a bent axle shaft as well, I mean tube, shaft, out of ballance gear assembly, it will all cause vibration.
That rear axle could have really been worked hard before you got it and it could be complete junk.

[jlsanborn]

Ol' Elco swapped entire rear end assemblies and the vibration didn't change. I suppose it's possible that both housings were less than straight or there were two crook axles but it sure seems odd. I'm leaning towards them muffler bearings! I know I've seen bmerdoc on here or you over there.... any input from him on this?

[Xeen]

These trucks are old I'm sure alot of the rear axles are bent from abuse, you could probably line up 10 of them and 6 will be less than straight, if you think about it most people overload their half tons.
I'm not real optimistic that the 70 rear axle I got for my truck is straight.

[litew8]

Dang, I thought it'd be the a-arm bushing causing it. hmm Have you tried rotating tires? Maybe one is bad.

[Low Elco]

Originally Posted by Xeen

These trucks are old I'm sure alot of the rear axles are bent from abuse, you could probably line up 10 of them and 6 will be less than straight, if you think about it most people overload their half tons.
I'm not real optimistic that the 70 rear axle I got for my truck is straight.

I'm hip, but literally the same thing since the start. Your figures are probably right, though.

[Low Elco]

Originally Posted by litew8

Dang, I thought it'd be the a-arm bushing causing it. hmm Have you tried rotating tires? Maybe one is bad.

Three different sets in the rear, two in the front. Same same.

[Low Elco]

Took tonight off, was really tired. I appreciate everyone's attention and suggestions, keeps me from thinking I'm going nuts!

[Xeen]

I dunno man the rear axle just seems like the most likely candidate to me, if you had the driveshaft checked for ballance then the rear axle is the only other thing that would cause major vibration like that other than running your tire pressure way too low but it would have to be down to like 20 pounds or less, pump them up to 35 pounds and see if it goes away.

[litew8]

Harmonic balancer? U-Joint? Flywheel? Torque Converter? Timing?

[Xeen]

Originally Posted by litew8

Harmonic balancer? U-Joint? Flywheel? Torque Converter? Timing?

Ok well if its those things then putting the transmission in neutral and reving the engine all the way through the RPM band would give you the answer.

[Bomp]

This might sound really stupid but I've done it and its amazing when you do find something that catches your eye.
I find an old abandoned road and have the wife drive. Talking to her on the cell so that she don't just take off, I drive along side,behind,other side, have even ridden in the back of a pickup to look at the front of the truck, and listen/watch to see if I can notice anything. The "vibe", look for the "vibe".
This hasn't worked for me every time but when it gets to the point of "Im thinking Im nutz" its worth a try.

[Low Elco]

Bomp, that's the next thing I'm doing, the "drive along". We've eliminated drivetrain. Varying engine speeds, no different. Pulled the shaft, left the motor off, pulled it with the big truck on a strap, same same. Getting ready to use my friend's gopro to do what Bomp's suggesting under the truck. We'll see. Boppa called tonight and said that the throb started after the brake job, so there's another place to look.

[Vic1947]

Originally Posted by Xeen

These trucks are old I'm sure alot of the rear axles are bent from abuse, you could probably line up 10 of them and 6 will be less than straight, if you think about it most people overload their half tons.
I'm not real optimistic that the 70 rear axle I got for my truck is straight.

Originally Posted by Low Elco

I'm hip, but literally the same thing since the start. Your figures are probably right, though.

Chip, If checking the balance on the brakes doesn't turn up anything, my offer still stands to throw the line up bar in the rear housing and true it up.

[Low Elco]

Thanks, Vic. I may swap out some of these new wheel bearings while I'm at it, they're a little looser in the cages than I'd like. What's everyone's magic formula for setting wheel bearings?
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[FrankieD]

Originally Posted by Low Elco

Thanks, Vic. I may swap out some of these new wheel bearings while I'm at it, they're a little looser in the cages than I'd like. What's everyone's magic formula for setting wheel bearings?
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Grease bearings so it comes out both sides rotate in your hand then and smear grease around the outside set the bearing in tighten till you feel drag when spinning the tire then back off till free then set the nut for the cotter pin, grab the tire and pull on it side to side and top to bottom to make sure there is no movement in the bearing and you should be good.

[Xeen]

Originally Posted by Low Elco

Boppa called tonight and said that the throb started after the brake job, so there's another place to look.

Thats a critical piece of information, if its true then thats the first place to start and is in line with my very first suggestion which is to put the drums on a high resolution wheel ballancing machine and find out if they are ballanced properly.
You could also grab the axle shaft with both hands and find out if there is an unusual amount of play, IN and OUT, or UP and DOWN on both sides.
On a personal note, I'm sorry you are having this much trouble, troubleshooting is my thing, if I were there I could figure this out pretty quickly, but I would let Vic help you with it the guy knows what hes doing, however if you dont get this figured out I am only about an hour away from you and I can certainly give it a shot.

[Low Elco]

Yeah, I was glad he called. To be specific, we're talking front brakes. He says he was chasing a vibration and did the brakes. The throb started and picked up after that. Rotors are on my floor as we speak. Calling a balancing guy today, and some of the new bearings seem a tad loose. Gives me something to go on at least.
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[Xeen]

Originally Posted by Low Elco

Yeah, I was glad he called. To be specific, we're talking front brakes. He says he was chasing a vibration and did the brakes. The throb started and picked up after that. Rotors are on my floor as we speak. Calling a balancing guy today, and some of the new bearings seem a tad loose. Gives me something to go on at least.
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Hmm it sounds like to me it was already vibrating before he changed the front brakes so I think that is probably unrelated but you can check to see if there is too much play in the bearings on the front disks just for the heck of it, just to cover my bases here when he "did" the brakes what did he do exactly, did he change the rotors out or just the pads?

[jlsanborn]

Can't wait to see the GoPro vid!!! Donuts?

There's no doubt that any rear end housing is going to be "out" to some degree and its very possible that both you've tried were subject to prior abuse and could be tweaked. How bad does it have to be to cause this kind of issue? Would a good alignment shop be able to see this when they look at thrust angle? How bad would a rotor or drum have to be out of balance? 65mph is less than 1000 rpm right? Yeller has got to be as tight as any ride on here by now so when you find that gremlin you'll know everything else is GOOD!

[Low Elco]

There was a small tire-type vibration traced to a bent front wheel, which has been replaced, balanced with .5 oz.. In the process, Boppa replaced the whole assembly, rotors, seals, bearings, the whole thing. Throb started after this, so we'll see.
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[Low Elco]

Originally Posted by jlsanborn

Can't wait to see the GoPro vid!!! Donuts?

There's no doubt that any rear end housing is going to be "out" to some degree and its very possible that both you've tried were subject to prior abuse and could be tweaked. How bad does it have to be to cause this kind of issue? Would a good alignment shop be able to see this when they look at thrust angle? How bad would a rotor or drum have to be out of balance? 65mph is less than 1000 rpm right? Yeller has got to be as tight as any ride on here by now so when you find that gremlin you'll know everything else is GOOD!

No donuts, one wheel peel! It'll do that till you take your foot off it, though!
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[sduckworth13]

Chip, I might have missed it but did you check the pinion angle and even if the pinion angle is right, the yolk might pulled out or pushed in too far from lowering it. I'm guessing its the driveshaft. Does the driveshaft make any clunk noises? I'm not a professional or qualified shade tree mechanic but, I was having the same issues with my 67 gmc when I lowered it 4/6.
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[sduckworth13]

Good luck finding the problem. Hope it's quick fix and cheap,
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[jlsanborn]

Originally Posted by Low Elco

No donuts, one wheel peel! It'll do that till you take your foot off it, though!
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Ok! That'd still make a sweet vid!