sixb
1/2 ton status
I've always wanted a back yard shop big enough to house my Machine shop but maybe that's not such a good idea
CK5
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The Story Of A Cummins Suburban (Lots Of Pics)
- Thread starter mosesburb
- Start date
kevin wcmo
Registered Member
hey super build. been subscribed from the beginning. i am in the process of getting good and started on putting in a 98 6bt into a 70 3/4. alot of helpful ideas you have presented. 
my question is what did you use for front springs? it looks like they have about 4" of lift. how are the road manners after driving for a while? tia
kevin
my question is what did you use for front springs? it looks like they have about 4" of lift. how are the road manners after driving for a while? tiakevin
It really is. Of all the mchine work that was painted black, it is my favorite piece.
Yes he did. But the funniest thing was the next morning when he is all ready to go outside and work some more. "When are we going out to the shop??" I go out there and he comes out to help and ends up riding his bike up and down the sidewalk. So much for another day's work I guess.
I've always wanted a back yard shop big enough to house my Machine shop but maybe that's not such a good idea
Well, this is a smallish two car garage that has about four cars worth of machine shop in it. I keep telling him he needs a TIG welder and that I would store it for him--just because I am a nice guy.
hey super build. been subscribed from the beginning. i am in the process of getting good and started on putting in a 98 6bt into a 70 3/4. alot of helpful ideas you have presented.
kevin
The front springs are 4" Tough Country E-Z Rides. I do not know what the actual lift is though. A friend of mine had another '72 K20 Sub with a 6" lift and 37's(??) and it sat the same height as mine with a 4" and 33's, so who knows.
It rides and drives great. As soon as I started driving it it became my daily driver. It goes down the road straight, rides nice, corners well, stops great. It really is a nice machine to drive.
Last weekend the machine went on its first road trip. We went up north, about 135mi to a friends house in the middle of nowhere at about 7200' elevation. The Cummins ran great. I pulled the 7% grades at 75mph with throttle to spare. Had great weather going up. To get to his place you have to look for mile marker number something, then go half mile past, look for a locked Forest Service gate, unlock, re-lock, then you have a 1.5mi linear mud bog to get to a 10% grade, pull that and poof, you have arrived.
Going in:
It was real muddy. I learned last time that this mud is like super epoxy. Whatever it gets on, it stays on--clothes, shoes, trucks, anything. nasty stuff.
Near the end we picked up enough elevation and there was enough shade that the road was still frozen:
I did some work on his carburetor and had some fun for a few days, then it was time to leave. As we finished packing up, the snow flurries started. Just barely enough to be able to see. As we got to his property line a couple hundred yards away, the flakes got bigger:
By the time we got out to the gate, the flakes were getting larger:
By the time I got the gate unlocked, re-locked and unlocked my hubs, the flakes were pretty huge:
A few miles down the road we were seeing this:
A couple miles after that the road turned into this:
Shortly after that, the road turned into this:
I talked to my buddy today and right now they have four feet of snow on the ground and another storm coming in Tuesday night.
All in all it was a great long weekend. I learned that the Cummins does not appreciate being awakened below 32deg. I did get it started, but it did not want to. It was running on approximately two cylinders and dragging the other four along for the ride until I threw the grid heater switch and almost immediately it smoothed out and would run without my foot holding the throttle on the floor.
As far as the drive goes everything was great. My windshield washer setup (pushbutton auto detailer) was fantastic. I used it many times and except for when it was frozen solid, it was great. The truck drove great overall. The ONLY issue I have with it is a driveline-type vibration at 60-65 under power and 65+ under power but significantly less powerful. Also I learned that I can not coast down a hill over 65--under 65--fine, over 65--BAAAADDD!! I can either float or power down the hill but I can not coast or a horrible constant frequency harmonic vibration resonates throughout the entire truck (in or out of gear). I have tried different driveline angles, pinion angles, lowered the t/case, replaced some spring bushings, re-torqued every fastener I can find and nothing changes. I am going to have the driveline balance re-checked. I highly doubt that to be the issue as I have never had the slightest problem with any driveline that I have had done by the guy who did this one for twenty or so years. I hope someting is wrong with it just so I can be done with this, but I am not holding my breath.
Other than that it was a very enjoyable drive and fun to see this thing out in the woods finally.
Going in:
It was real muddy. I learned last time that this mud is like super epoxy. Whatever it gets on, it stays on--clothes, shoes, trucks, anything. nasty stuff.
Near the end we picked up enough elevation and there was enough shade that the road was still frozen:
I did some work on his carburetor and had some fun for a few days, then it was time to leave. As we finished packing up, the snow flurries started. Just barely enough to be able to see. As we got to his property line a couple hundred yards away, the flakes got bigger:
By the time we got out to the gate, the flakes were getting larger:
By the time I got the gate unlocked, re-locked and unlocked my hubs, the flakes were pretty huge:
A few miles down the road we were seeing this:
A couple miles after that the road turned into this:
Shortly after that, the road turned into this:
I talked to my buddy today and right now they have four feet of snow on the ground and another storm coming in Tuesday night.
All in all it was a great long weekend. I learned that the Cummins does not appreciate being awakened below 32deg. I did get it started, but it did not want to. It was running on approximately two cylinders and dragging the other four along for the ride until I threw the grid heater switch and almost immediately it smoothed out and would run without my foot holding the throttle on the floor.
As far as the drive goes everything was great. My windshield washer setup (pushbutton auto detailer) was fantastic. I used it many times and except for when it was frozen solid, it was great. The truck drove great overall. The ONLY issue I have with it is a driveline-type vibration at 60-65 under power and 65+ under power but significantly less powerful. Also I learned that I can not coast down a hill over 65--under 65--fine, over 65--BAAAADDD!! I can either float or power down the hill but I can not coast or a horrible constant frequency harmonic vibration resonates throughout the entire truck (in or out of gear). I have tried different driveline angles, pinion angles, lowered the t/case, replaced some spring bushings, re-torqued every fastener I can find and nothing changes. I am going to have the driveline balance re-checked. I highly doubt that to be the issue as I have never had the slightest problem with any driveline that I have had done by the guy who did this one for twenty or so years. I hope someting is wrong with it just so I can be done with this, but I am not holding my breath.
Other than that it was a very enjoyable drive and fun to see this thing out in the woods finally.
MaxPF
1/2 ton status
Looks like you were driving down Hwy 260 along the Rim. Am I correct?
Dumb question, but did you check you balance in your tires. I sounds like you've checked everything drive-train wise but the tires.
I was thinking he was up on 87, near Blue Ridge
No, but the last pic is about 1.5mi before I took a RH onto 260 toward Camp Verde.
Wow. One of the middle pics is actually right past the road to Blue Ridge. Very nice.
If that is a dumb question, then I have a dumb question for you--can tires make a harmonic type vibration?? I have never had a tire make a vibration like this. Any tire balance issue I have had was more of a "bouncing" type vibration as opposed to a deep harmonic type. I realize tire vibration can be speed related, but can it be related to power/float/coast?? The reason I have not had them checked is because I did not think tires could make a vibration like I have. Man that would be great if this could be solved by a simple re-balance of some tires.
MaxPF
1/2 ton status
Darn! Travis got it right 
It looks like we all hit some of the same stomping grounds though
I had the same type of vibration. When I took out my rear driveshaft to do my Cummins swap I found out that my pinion-side u-joint was completely wasted and so was my pinion bearing
CV's are another culprit, as are worn slip yokes or driveshaft slip joints...
It looks like we all hit some of the same stomping grounds though I had the same type of vibration. When I took out my rear driveshaft to do my Cummins swap I found out that my pinion-side u-joint was completely wasted and so was my pinion bearing
CV's are another culprit, as are worn slip yokes or driveshaft slip joints...
Darn! Travis got it right
I had the same type of vibration. When I took out my rear driveshaft to do my Cummins swap I found out that my pinion-side u-joint was completely wasted and so was my pinion bearing
Part of the reason I am hiving so much difficulty with this is everything you mentioned on yours is new on mine. From the bellhousing back, every bearing is brand new, the driveshaft was just re-done, and I just went through the rear axle. As I mentioned before, I am going to take my drive shaft back to my drive line guy and have him re-check it. I am really hoping he had a bad day when he did it the first time, but with my luck, I'm not betting on it.
MaxPF
1/2 ton status
Is it a 1 piece shaft or 2 piece? If it's 1 piece, I wonder if it is on the verge of being too long. Otherwise, I'm out of ideas too
Is it a 1 piece shaft or 2 piece? If it's 1 piece, I wonder if it is on the verge of being too long. Otherwise, I'm out of ideas too
1 piece. Description from an earlier post:
In my initial plan, I was going to need a two piece drive shaft due to length. Well, as it worked out, I had to run a one piece because I had a lot less room than I initially thought I would have. No biggie, other than I had bought a super-nice two piece shaft out of a late model. I really did not want to scrap this shaft so I found the driveshaft company that I have used for the past 18-20 years. They had moved, but I located them and one of the guys still worked there. I explained what I wanted to do and he said it could be done. What I had him do was take the front half of the two piece, swap it end-for-end, knock the carrier bearing off and machine the ends so it could be re-tubed with the heavier .083 tubing. It worked out perfect and he said the factory Spicer u-joints were still in great shape, so he left them in rather than selling me new ones.
Here is what I ended up with:
MaxPF
1/2 ton status
Maybe it's just me, but it looks awful long... 
EDIT: Now that I look at it some more, it doesn't look too bad. I dunno...
EDIT: Now that I look at it some more, it doesn't look too bad. I dunno...
Maybe it's just me, but it looks awful long...
EDIT: Now that I look at it some more, it doesn't look too bad. I dunno...
It is somewhere around 54-55".
Darn! Travis got it right
...
WAYYY back when I fought forest fires I was stationed @ Blue Ridge - I have driven that stretch of road MANY, MANY times, plus when we lived in Mormon Lake, we drove 87 to Tempe most of the time, the last pic sealed the deal for me.
Just a suggestion since you have tried everything else.
Heck your brake drums could be out of balance.
Another suggestion is pull the rear drive-shaft out and drive around on the front axle and and see if you still have vibration.
Another suggestion, when you pull your drive-shaft out to get its balance checked, pull the yokes also and have those balance with the drive shaft.
Brother Nick....my gut says to get those tires road forced! Page 16 shows pics of the stock steelies and the mags....i didn't see any weights on the rims. And do not go the tape weight route...hang the weights on front and rear! Tape weights will not stay put...at least in the oil patch they won't....
DW
DW
Definite possibility, but I can't see it being power related.
Man, I really wanted to try this (even before you posted it), but being that the vibration is over 60mph, I was very nervous about doing this. I discussed it with my driveline guy and he was not liking the idea too much because of the speed and available torque. Also, the day before I had the shaft re-ckecked, azblazer (the guy from the post right after yours) had a front shaft come unwound at speed and the list and cost of what it destroyed convinced me I really did not want to do this even though I wanted to.
When the driveline was re-checked, he moved one weight about 1/8". I stated that it did not seem like that would do much and he said it really wouldn't, but in the name of perfection, he dicided to move it slightly just to be sure. I made no difference at all. I even tried swapping the shaft end for end--no difference there either.
The wheels/tires are all balanced, just no weights visible on those tires I guess. I watched the guy do the balancing and he did it to zeros. The truck drives absolutely beautiful--two fingers on the wheel type thing.
Well, with some help from some friends, I FINALLY got my BFG Mud tires on. A big thanks goes out to Jason4x4 who not only found the last wheels that I needed, but also mounted and balanced them for me on his lunch hour. I would not have thought that finding what has to be the most common eight lug steel wheel on the planet would be so difficult, but every time I had something set up, it went to hell in a handbasket. Either the wheels were wrong or the person flaked out or, or, or...Jeez.
Anyways, I took a nice drive down to his place of employment with my wheels and tires and he put them all together. I brought them home and had to put them on as I was too anxious to see how it looked and also to see if my vibration would go away (more the latter, but I did want to see what it looked like).
So, without further delay: (It was overcast today so the pics aren't as bright as the should be)
A front view:
Now with the ever timeless hub caps:
So, all in all I like the look of it. It changed the entire image of the truck. The unfortunate thing is it also changed how it drives. The truck definitely has to be DRIVEN now. Not quite NASCAR sawing at the wheel, but it definitely requires attention going down the road.
So, now for the question you all are wondering about: Did the vibration go away??
Wait for it....
Nope. Nothing changed. The vibration is still alive and well. I guess that rules out the tires/wheels/balancing from the equation.
Damn. Thanks again Jason!!
Anyways, I took a nice drive down to his place of employment with my wheels and tires and he put them all together. I brought them home and had to put them on as I was too anxious to see how it looked and also to see if my vibration would go away (more the latter, but I did want to see what it looked like).
So, without further delay: (It was overcast today so the pics aren't as bright as the should be)
A front view:
Now with the ever timeless hub caps:
So, all in all I like the look of it. It changed the entire image of the truck. The unfortunate thing is it also changed how it drives. The truck definitely has to be DRIVEN now. Not quite NASCAR sawing at the wheel, but it definitely requires attention going down the road.
So, now for the question you all are wondering about: Did the vibration go away??
Wait for it....
Nope. Nothing changed. The vibration is still alive and well. I guess that rules out the tires/wheels/balancing from the equation.
Damn. Thanks again Jason!!
i don't remember if you went through the axles or not, maybe a bent or poorly machined shaft or housing? i wouldn't think it would be drums since they shouldn't be touching the pads at 60. possible it's a warped rotor.
after rereading, if it requires that much maintenence to stay between the weeds, i would think it might be an alignment issue bad tierod ends or loose kingpin causing slight death wobble, maybe toe in isn't quite right.
after rereading, if it requires that much maintenence to stay between the weeds, i would think it might be an alignment issue bad tierod ends or loose kingpin causing slight death wobble, maybe toe in isn't quite right.
