73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: fitz on July 31, 2014, 08:39:16 pm
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I have an M1028 (basically an 84 k30) that has the death wobble in the Dana 60.
Ever since I bought the truck last year it had a little shimmy to the front end going over potholes/railroad tracks.
I just installed Tough Country 2" HD front springs. Now the shimmy has become the dreaded D60 death wobble
I installed new Spicer springs & plastic bushings but that didn't solve it. I rotated the tires and tried another set of tires I had laying around but that didn't help.
I've been reading a bunch of threads about rebuilding the whole unit with new kingpins and bearings. I still have more research to do but I am concerned with the kingpins 600 foot pound torque requirement on the 7/8" allen head. Most of the threads just say to use a 4' pipe on the allen head to tighten the kingpin. I've found some torque wrenches rated up to 600 foot pounds for about $300.
So should I spend the $300 or just use a 4' pipe and crank it down hard?
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do you already have a tq wrench? if so i would waist money on one already maybe find someone who has one that big. if no then i would buy one cause you might need it again.
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I have a craftsman 3/8" (75 ft pounds) and a craftsman 1/2" (200 ft pounds). A 600 ft pound one might be next.
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a home made deal would be something like this
WHAT YOU NEED---600
How much you weight ---250 (IDK)
N/W=X * 12(inches)= you pipe length
so you need 600/250=2.4*12=28.8
now take a pipe or something and make a mark from the center of the alen key to 28.8.
now once you snug the bolt up you put all you weight on that 28.8" mark and that will give you 600lbs if you weight 250lbs
if you dont understand just tell me your weight and ill tell you where to put the mark ;-)
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must add make sure your pipe is perpendicular to the bolt and dont jump on it ::)
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Thanks Irish.
As far as the 250lbs, your right on the money (mom says I'm just big boned).
I'm thinking I might have to take the axle out of the truck and rotate it 90° to get the pipe perpendicular to the kingpin.
I'm not against spending money on tools, I just can't see myself using a 600 ft pound torque wrench that often.
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Is there no place around you that you could rent one for a day ? I would be hesitant on not torquing it properly, the last thing you would ever want is for it to come apart when you are driving it.
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You could probably have an extension made with a receiver for your torque wrench! A torque wrench is no magical mysterious device! torque is simply a force applied at a distance. 200 lb-ft is 200 lb applied at a distance of 1 ft from the fulcrum...or 100 lb applied at a 2 ft. distance.
You said that you have a 200 lb-ft torque wrench. In order to apply 600 lb-ft of torque you need a longer lever arm.
The formula to determine that is: wrench setting = desired torque x wrench length / (wrench length + extension length)
So...if you have say an 18", 200 lb torque wrench and you need to apply 600 lb-ft of torque you would need to have at least a 36" extension with your torque wrench set to 200 lb-ft.
200 lb-ft = 600 lb-ft x 18"/(18" + 36")
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I'm leaning towards just spending the $300 on the torque wrench. I plan on keeping this truck so I might as well bite the bullet. This project is gonna be few weeks away. I'm sure I'll have more questions when I start.
Thanks again guys.
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First off how much wear is actually on the king pin itself? You may be barking up the wrong tree. Of the 60's I've rebuilt I have used a tourqe multiplier tool. It's a gear to gear torque increase tool. Example 75ftlbs in 750 lbs out. Concerning the wobble, your on the right track with the springs. My guess is the new springs were about 1/2 inch or taller than the wore out springs. Next culprit is tie rod ends ,drag link, bottom bearing and then last the kingpin. There's actually a fix for adjusting spring tension on theses 60's, low tech is shimming the spring. High tech they make a replacement top for the springs with a set nut and bolt that screws down force on the spring kinda like a set screw.
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On the two Dana60s I rebuilt I used the bubba method......Haha!
Here is how I did it:
I used my SnapOn 1" drive 7/8 Allen driver ($$$$$), and standard 3/4" drive breaker bar, with my SnapOn 3/4"~1" adapter. (more $$$$$$)
Then I used a 6' cheater pipe. Using a standard bathroom scale I pushed against the bathroom scale which was pushing against the 6' end of the cheater pipe. When the bathroom scale read, and would hold 100# I stopped. Voila, 600 ft/lbs.
After many miles none have came loose. Red loctite doesn't hurt either....
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As pholliday said, I shimmed the springs on the bushings.
There is also a company that makes a bronze bushing that replaces the nylon Spicer OE piece.
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You could probably have an extension made with a receiver for your torque wrench! A torque wrench is no magical mysterious device! torque is simply a force applied at a distance. 200 lb-ft is 200 lb applied at a distance of 1 ft from the fulcrum...or 100 lb applied at a 2 ft. distance.
You said that you have a 200 lb-ft torque wrench. In order to apply 600 lb-ft of torque you need a longer lever arm.
The formula to determine that is: wrench setting = desired torque x wrench length / (wrench length + extension length)
So...if you have say an 18", 200 lb torque wrench and you need to apply 600 lb-ft of torque you would need to have at least a 36" extension with your torque wrench set to 200 lb-ft.
200 lb-ft = 600 lb-ft x 18"/(18" + 36")
idk if this is true or not in my mine the tq wrench will still trip at 200 ft lbs. it would just take less weight to make it trip
but on the side note i did see one of those tq multiplier the other day on the snap on truck
(http://www.protorquetools.com/DSN/wwwyourtoolprocom/Content/Images/Torque/TM1000.jpg)
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The new springs were about 1/2 longer than the old ones. The old bushings didn't look worn (I was hoping they would be shot so that would fix it). I took the truck down for the state safety inspection today (no emissions needed) and it passed. The inspector said everything in the front end looked good. He said the drag link had a tiny amount of play but that it was within spec. I just went to Napa and ordered 2 drag link ends and the adjuster sleave.
As far as the bronze sleeves go, l looked into them but they are only recommended for off road use. I'm gonna try shimming the springs with washers to see if that helps, but not sure if that's just masking other problems.
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what about shocks? i know my impala has bad struts and shes all over the place with even the slightest bump
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The front shocks were replaced 2 weeks ago when I did the 2" lift.
I
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Concentrate on tie rod ends and drag link. Death wobble is a partial product of lack of preload on your steering knuckles. Kinda shouldn't need to shim new springs. When you have tie rod off check resistance of each steering knuckle separately. With the tire on and tire off the ground get a long pry bar and really check six to twelve play on steering knuckle each side. On a properly maintained 60 you only really need one steering stabilizer. If more stabilizers are needed then that's just covering up another problem.
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I had some time to play around with it today (Napa will have the drag link in Monday or Tuesday). I found a little play in the front wheel bearings. On one side (passengers) the spindal nuts were only hand tight.
I was able to unscrew them by hand and go to Advanced Auto to get a spindle nut socket (of course the ones I have for a 10 bolt and 14 bolt FF don't fit) I torqued the inner bolts to 50 ft pounds, backed them off 1/4 turn to line up the retainer plate, and then torqued the outer bolts to 70 ft pounds. I thought for sure this was gonna solve it. No such luck. I will Waite for the drag link.
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Spindle nuts will contribute to vibration not necessarily DW (death wobble) also beware of changed caster as it relates to changing or modifying front spring hanger ( longer spring shackle the more it changes caster). Your going to have to buy a new tie rod as one side opposite the adjustable sleeve is generally not rebuild able
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pholliday-
Edit your post to say caster not camber.
Camber is fixed, and non-adjustable on a kingpin Dana60 axle.
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Pholiday, its funny that you mentioned the spring hangers. When I ordered my springs (tough country 2" hd's) I also bought the O.R.D. heavy duty shackles. These shackles are 1/2" longer than my stock 1984 shackles. The new shackles are the same length as the 1988-1991 Blazer/suburban/1 ton shackles.
My game plan now is to change the drag link and the tie rod. Hopefully that solves it, if not, should I put the stock shackles back in? I will have to drill out the shackle bolt holes from 7/16" to 1/2" . My new springs are already set up for the 1/2" bolts.
Thanks again.
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fitz-
Death wobble is the result of improper caster settings for your size of tire. If you look at any of the Ford SuperDuty boards, Dodge Ram boards, or Jeep boards there are guys who are constantly complaining about their SFA trucks. Many of those guys find that by playing with caster it fixes the wobbly bobbly of their trucks.
I don't know how much of their trial and error works, and what not, but.....
Years ago I had 8" Skyjacker front springs on my '77 with a Dana60 front axle. For steering correction I ran the Skyjacker dropped pitman arm, and the steering block. All I had was 1 stock steering stabilizer.
The Skyjacker springs had a caster shim that they came with as a correction for the front u-joint angle. I wasn't worried as much about u-joint angle as I was about the two bolts that hold the leaf spring to the axle housing on the passenger side. I was worried that by having the shim in place it would put too much of an angled load on the bolt head so I took out the shim that put the caster back to factory.
On my truck I ran 18.5/44-16.5 Gumbo Monster Mudders on 16.5x14" wheels and never once had any wobble issues.
After you get everything tightened up you may want to experiment with pulling the caster shims.
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My lift is only 2" so it doesn't have any caster shims on the spring pack.
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Thanks Engineer! Big whoops I know better than that. I'm also running 8" skyjacker with but with a shim and a slightly longer shackle. Step one make sure tie rod/ drag link are tight. Step two like Engineer said try adjuster caster with shim or shackle lenthgs you'll get it.
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I searched for awhile but couldn't find a torque spec for the drag link & tie rod studs & adjusting sleaves.
Any suggestions? Thanks
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It's a little bit of a friction grip. Firm snug will be fine. As far as kingpins go the tighten the snot out of them they'll be fine. Haven't heard if one documented case of kings pins coming loose. It's pretty much a nonissue due to the lateral forces on them.
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I searched for awhile but couldn't find a torque spec for the drag link & tie rod studs & adjusting sleaves.
Any suggestions? Thanks
Tie rod and draglink ball studs = 70 lbs-ft
Adjusting sleeve bolts = 15 lbs-ft
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Here is a quick list of what I have done to try to cure the death wobble problem.
Replaced the kingpin springs & bushings with new Spicer parts.
Adjusted the front wheel bearings ( they had a little play in them).
Replaced the complete drag link with new parts from Napa.
Rotated tires & tried another pair of front tires (trying to rule everything out).
So far the the DW is still here ( I have a pothole filled road 1/4 mile from home to test my progress on).
I just ordered the complete tie rod & steering stabilizer from Napa. I'm not expecting the steering stabilizer to work miracles, just figured I'll replace it while its out.
This weekend I'll install the tie rod & steering stabilizer, hopefully this solves it. My next move, if needed, will be to replace the Off Road Design shackles with the stock ones.
Thanks to everyone who has given me advive
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Have you checked the 6 to play in the bottom knuckle bearing?
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I will check that tonight when the tie rod is off. When I put a pry bar under the tire should I get any play when I rock the tire in the 6-12 position.
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Sorry meant 6 to 12 play, but I see you caught that. Your 6-12 should little (very little) to none. The bottom bearing on the knuckle is your pivot point and on top your spring provides the preload that keeps things "snug".
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Its a victory.
I checked the 6-12 play with a crow bar and everything seemed tight.
On to the tie rod & steering stabalizer.
I set up the new tie rod using the same method I used on the drag link. I used my $10 Harbor Freight micrometer to measure the exposed threads on each end of the old parts at the adjusting collar. I installed the new parts to the same measurements, then verified overall length with a tape measure.
One more thing I did to check my work was the "poor mans alignment". I bolted a piece of 30" angle iron to the rotor on each side of the truck ( using the lug nuts). I then measured the distance across, and verified it was the same with the new tie rod installed (it was). I figure the truck went down the road straight & the steering wheel was straight before my work, I'm just trying to cure the DW.
I also installed the new steering stabilizer. Once I removed the old one, I could push it in/pull it out with no resistance (not a good sign).
I finished up and drove it down "death wobble road" as I call it. Smooth as can be, or at least as smooth as a 5/4 ton Military truck with 2" HD springs can be. I couldn't believe it. I did a u turn and tried it again, no death wobble.
Pholliday1 made reference to a "well maintained Dana 60", I think I'm getting there. I adjusted the wheel bearings, but I will pull them apart and repack the bearings, then I should be done.
A sincere thank you to everyone who offered me advice.
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Big win for the home team!!!
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After declaring victory on the Dana 60 my next goal was to figure out how to post pictures on my so called "smart phone".
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what were the boxes on the driver's side of the bed for?
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Those brackets are the antenna mounts for the Military communications radio. These old trucks have some cool features. Those hooks on the front & rear bumpers tie into the frame and can be used to airlift the truck. The rear pintle hitch swivels 360°. Check out the tool kit behind the seat. Lots more cool stuff on it. I can take more pictures if anyone is interested.
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I can take more pictures if anyone is interested.
I'd enjoy seeing more. Those are neat, purposeful vehicles. Thanks, Fitz!
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These trucks have a 24V/12V electrical system. The starter & glow plug system operate on 24 volts. Everything else is 12 volts. The way I understand it is that it was designed so you can jump start it of any heavy equipment (24 volts) that the Military owns. If the pick up has dead batterys, a big rigs 24 volt system can power up the pick ups starter and glow plugs to get the 6.2 to fire up. The 6.2 diesel has dual altanators. That round port on the passanger side grill is where the Military slave cable ( jumper cables) plugs in.
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The Military chains everything down on these trucks. Check out the security system (chained up steering wheel), fuel cap chain, and wheel chocks.
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That behind the seat shovel, axe and pick-axe set is pretty cool! How does the pick-axe head attach to the handle? I would like it to be very secure!
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I've never had the toil kit out to check on it. Another cool feature is the riffle holders behind the sear for the passanger and driver.
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I like that... a "toil kit." ;D