1972 Highboy Build Progress
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Joined: Jun 2017
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From: Western Australia
Fantastic build, so far. Great reading, having the technical and the personal backstory, made for as said a great read. The technical information is first class. I'm currently in search for a project truck of this vintage...the search continues, threads like this are invaluable to me.
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To actually check and verify the final free-play setting you would need to set up a dial indicator to measure the in-and-out movement of the hub on the bearings and spindle.
If you don't have one, or can't easily borrow or rent one, then you just have to trust the method described in the book and hope that all the parts cooperate. The idea of the final measuring is to verify that all the parts are still within parameters and that when adjusted to spec, fall into the correct range of movement.
However, you can still do a casual check by hand. While I don't know that you can feel a .001-.003 inch amount of movement, I know for a fact you can feel .005-.006 inch freeplay, if you're careful and sensitive to the movement.
With the bearings adjusted and locked down, you can grab the hub/drum/rotor/wheel (whatever is still bolted to the hub, if anything) and try to move it in and out, or top and bottom, or front to back. As you rock it with your hands, if you can just barely feel/hear/sense the tiniest amount of movement in the hub, perhaps even accompanied by a faint "tick tick" as you move it back and forth, you're probably within spec.
If you ever have the chance to compare your personal "feel" for stuff, vs what it says on an instrument like a dial indicator, I'm sure you would be able to tell the difference between, for example, .0005" and something over .010" such as .015" or so. You'd know from experience that this larger amount of play is notably more than your correct experience of five-thousandths. But that's all moot if you can't get your hands on some measuring tools.
If that's the case, then you just have to trust that the tiny amount of play you feel is going to work out for you. And always make sure to keep the gear lube topped up because on a full-floater rear end the grease you put in the bearings is just to keep them safe for the first few minutes of use. After that the gear lube is what keeps the bearings rolling freely and cooled when worked hard. With luck, for the next 40 years or 100,000 miles. Whichever comes first.
Hope that wasn't too much info. Just wanted you to know what you're looking for and that you can indeed feel 5 thousandths of an inch of movement. But only just barely. If you're ham-handed (not an insult, just an acknowledgment of a fact of life) and in a hurry, you might not even feel it. Especially with new grease in there. But then that's the whole reason for the initial 50lb squeeze job anyway. To make it easier to measure the movement without excess grease skewing the results.
Good luck! When you're ready to do it just come back here and we'll shout out words of encouragement (as we sit in our lawn chairs drinking cool and frosty beverages and pointing and laughing in your general direction of course) and wisdom.
Paul
If you don't have one, or can't easily borrow or rent one, then you just have to trust the method described in the book and hope that all the parts cooperate. The idea of the final measuring is to verify that all the parts are still within parameters and that when adjusted to spec, fall into the correct range of movement.
However, you can still do a casual check by hand. While I don't know that you can feel a .001-.003 inch amount of movement, I know for a fact you can feel .005-.006 inch freeplay, if you're careful and sensitive to the movement.
With the bearings adjusted and locked down, you can grab the hub/drum/rotor/wheel (whatever is still bolted to the hub, if anything) and try to move it in and out, or top and bottom, or front to back. As you rock it with your hands, if you can just barely feel/hear/sense the tiniest amount of movement in the hub, perhaps even accompanied by a faint "tick tick" as you move it back and forth, you're probably within spec.
If you ever have the chance to compare your personal "feel" for stuff, vs what it says on an instrument like a dial indicator, I'm sure you would be able to tell the difference between, for example, .0005" and something over .010" such as .015" or so. You'd know from experience that this larger amount of play is notably more than your correct experience of five-thousandths. But that's all moot if you can't get your hands on some measuring tools.
If that's the case, then you just have to trust that the tiny amount of play you feel is going to work out for you. And always make sure to keep the gear lube topped up because on a full-floater rear end the grease you put in the bearings is just to keep them safe for the first few minutes of use. After that the gear lube is what keeps the bearings rolling freely and cooled when worked hard. With luck, for the next 40 years or 100,000 miles. Whichever comes first.
Hope that wasn't too much info. Just wanted you to know what you're looking for and that you can indeed feel 5 thousandths of an inch of movement. But only just barely. If you're ham-handed (not an insult, just an acknowledgment of a fact of life) and in a hurry, you might not even feel it. Especially with new grease in there. But then that's the whole reason for the initial 50lb squeeze job anyway. To make it easier to measure the movement without excess grease skewing the results.
Good luck! When you're ready to do it just come back here and we'll shout out words of encouragement (as we sit in our lawn chairs drinking cool and frosty beverages and pointing and laughing in your general direction of course) and wisdom.
Paul
Cargo Master
Joined: Nov 2005
Posts: 2,694
Likes: 45
From: La Ribera, Baja, Mexico
That is a great write up on bearing adjustment, and I have filed it in my 'Tips 'n tricks' file. On a slightly different topic, but still within the realm of wheels & bearings, I am being plagued with a 62 to 66 mph slight shimmy, on my 2007 MB diesel SUV. Yeah I know its not my old truck, but most on this site are pretty competent mechanics and I am looking for possible causes, and solutions. Naturally, I have had it to several local tire shops, for balancing and rotations, but the slight shimmy, noticeable in the steering wheel persists. It just appears at 62 or 63 mph and stops at 66 or 67 mph...??
I have thought of steering dampener, and bent rim, but nothing it obvious, and the wheel bearings appear to be within specs, having only the slightest of barely perceptible movement when off the ground. At 68 (via my marine GPS, the shimmy and steering wheel movement is gone and the ride is smooth.. ?? Any ideas would be appreciated, and sorry for the hijack...
Baja
I have thought of steering dampener, and bent rim, but nothing it obvious, and the wheel bearings appear to be within specs, having only the slightest of barely perceptible movement when off the ground. At 68 (via my marine GPS, the shimmy and steering wheel movement is gone and the ride is smooth.. ?? Any ideas would be appreciated, and sorry for the hijack...
Baja
Lead Driver
Joined: Jul 2017
Posts: 9,584
Likes: 1,168
From: San Jose, CA
Well it sounds straightforward initially at least. But the fact that you've already had at least one (sounds more like a couple?) round of rotating the tires and re-balancing, then it's going to be tougher to diagnose.
I would personally try rotating just one tire somewhere else. If you have shop tools and such and can do that yourself, take one tire from the front and put it on the back. See what changes, if anything.
If nothing, then take the two front tires and swap sides with them. See if anything changes.
This is more of a "I know it's been done, but this verifies they did their job" kind of thing. Unless you watched them an know exactly which tires went where when the shop rotated them, this gives you some more information to work with.
My reason for fixating on the tires is that wobbles, wiggles and shimmies almost always at least "start" at the tire. Where the rubber meets the pavement is where the action is usually.
Unless of course of the bent rim, or crooked component causes it, the tires are what's moving and pushing against the world. Even a full death-wobble has to start at the tires. Sure, other things being worn out or defective might allow it, but the tire is what causes it to start down that road.
So if you rotate the tires around you might at least see something that gives us a clue as to what is going on.
How old are the tires? Not how many miles necessarily, but how many years. And how is their tread wear? Any chopping or cupping? Unevenness across the tread?
Your narrow window of shimmy is not unheard of. But it's unusual enough to make it harder to track down the root cause.
Good luck. Maybe while you're rotating a tire you might find something visibly out of whack at one corner.
Paul
I would personally try rotating just one tire somewhere else. If you have shop tools and such and can do that yourself, take one tire from the front and put it on the back. See what changes, if anything.
If nothing, then take the two front tires and swap sides with them. See if anything changes.
This is more of a "I know it's been done, but this verifies they did their job" kind of thing. Unless you watched them an know exactly which tires went where when the shop rotated them, this gives you some more information to work with.
My reason for fixating on the tires is that wobbles, wiggles and shimmies almost always at least "start" at the tire. Where the rubber meets the pavement is where the action is usually.
Unless of course of the bent rim, or crooked component causes it, the tires are what's moving and pushing against the world. Even a full death-wobble has to start at the tires. Sure, other things being worn out or defective might allow it, but the tire is what causes it to start down that road.
So if you rotate the tires around you might at least see something that gives us a clue as to what is going on.
How old are the tires? Not how many miles necessarily, but how many years. And how is their tread wear? Any chopping or cupping? Unevenness across the tread?
Your narrow window of shimmy is not unheard of. But it's unusual enough to make it harder to track down the root cause.
Good luck. Maybe while you're rotating a tire you might find something visibly out of whack at one corner.
Paul
Cargo Master
Joined: Nov 2005
Posts: 2,694
Likes: 45
From: La Ribera, Baja, Mexico
A million thanks Paul, for the sound advice, and I will give that a try. I have an independent MB mechanic, that I have used for some years now, and if I do not find anything, or much at all, following your clues, then I will ask him to put it on the rack, and see if anything is obvious? The tires are 4 years old, wearing evenly, as far as I can tell, and have perhaps 1/2 the original tread. They are 17" Michelins, and have been rotated and balanced every 5 or 6K miles, and recently, 3 times, within the past 2 months, just chasing the wobble. I have used 2 different tire shops, just to eliminate the possibility of shop mistakes.. The wobble isn't bad, mostly annoying, when I am forced to drive in the mid 60 range. I will have my mechanic check the wheel bearings while he has it on the rack.. ?? Being a MB 320 CDI, with only 160K, I would not expect anything major in the suspension, and you are probably right, something with the tires, or a ever so slightly bent wheel. I have noticed, that most shops have a safety cover on the balancing machine, so they are not able to really check for a slightly wobbling wheel... My MB mechanic can do that...
Thanks again amigo
Russ
Thanks again amigo
Russ
Lead Driver
Joined: Jul 2017
Posts: 9,584
Likes: 1,168
From: San Jose, CA
Sounds good. Hope to hear a good result (eventually!) because yes, that is a really annoying thing!
Seems to me I've even heard of this issue with the diesel cars before. Hard to track down, and don't remember any solutions if I heard them. It's been years.
But with the heavier diesel engine up front, some of the suspension components do take a little more "beating" if you will. Sometimes as subtle as the front springs sagging out just a little bit extra and either putting something out of alignment, or even putting another component at the end of it's normal range. Just barely, which is why you get such a small shimmy and at such a small window of speed.
Of course, it's probably the most common speed you hit around home! That would be typical of what my grandmother used to say. "It's the innate cussedness of inanimate objects." and she was right!
Maybe check those wheel bearings real closely.
Paul
Seems to me I've even heard of this issue with the diesel cars before. Hard to track down, and don't remember any solutions if I heard them. It's been years.
But with the heavier diesel engine up front, some of the suspension components do take a little more "beating" if you will. Sometimes as subtle as the front springs sagging out just a little bit extra and either putting something out of alignment, or even putting another component at the end of it's normal range. Just barely, which is why you get such a small shimmy and at such a small window of speed.
Of course, it's probably the most common speed you hit around home! That would be typical of what my grandmother used to say. "It's the innate cussedness of inanimate objects." and she was right!
Maybe check those wheel bearings real closely.
Paul
Cargo Master
Joined: Nov 2005
Posts: 2,694
Likes: 45
From: La Ribera, Baja, Mexico
Will do Paul. Yep, the diesel engine in my MB SUV is a turbo, V 6 with 245 hp... I think, but do not quote me on that... It is a heavy bugger, with twice the sheet metal thickness as any other SUV, so I nicknamed it the "Panzervagon"... after the WWII German Tanks. If I am ever in an accident, the other driver will know for sure, that he hit a near immovable object. Very nice, and quiet ride though, and 21 mpg around town, and 26 on the highways... Since we spend about 8 + months a year, at our place in Baja, it is a garage queen most of the time.
The suspension has an air lift system, that can take the Panzer from 4" clearance to 16", depending upon roat and driving conditions. Also as an afterthought, I will have to get that checked too... could be more trouble than its worth, and as always, a lot more money than I like to pay...
Rubber side down amigo..
russ
The suspension has an air lift system, that can take the Panzer from 4" clearance to 16", depending upon roat and driving conditions. Also as an afterthought, I will have to get that checked too... could be more trouble than its worth, and as always, a lot more money than I like to pay...
Rubber side down amigo..
russ
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