Project: Custom 71 4x4 hotrod

[silver7]

Guess what - more issues. The closest size poly bushings I could find was 0.88" and the ID of my heim joint is 0.75". Needless to say grinding did not work and drilling the holes larger is not an option so I moved on to option #2. . .

3/4" OD, 1/2" ID high misalignment spacers. They arrived today from 'Barnes 4wd' and let me tell you - they work like a champ. After redrilling the holes to 1/2" I was able to put my joints together with my mount tabs and tack weld the rear mounts in place. Although they gave me more trouble than originally expected it was worth it. These traction bars will not only prevent axle wrap but they will also articulate well with my suspension. Here they are.

[brossow]

Originally Posted by silver7

These traction bars will not only prevent axle wrap but they will also articulate well with my suspension. Here they are.

Not crapping on this idea but honestly curious ... without any way for the bars to pivot at all, isn't this solid connection going to cause an incredibly jarring ride? I'm also not sure how it's going to articulate with the suspension as the bars are fixed length but when the axle moves it's not always the exact same distance from the front mount point of your traction bar setup.

Compare your setup with my Caltracs as shown in this thread. Here are a couple pics:





Notice how those pivot at the front to allow the axle to move as the spring compresses and extends. Now, I'm no engineer and I could be wrong, but that setup concerns me. Thought I should at least mention it, even if I'm completely wrong.

Brent

[silver7]

Yesterday's weather was perfect for working on the truck. Unfortunately, I had to use to use it to remove my faulty ABS system from my 2002 GMC Yukon. Today I get to bleed the brakes in the rain. Basically my ABS initiates at random - not a good thing. I had the repairs quoted at the dealership but the $1000 for parts and $400 for labor was absolute madness.

Luckily, I found a couple of companies on the web that will rebuild them for $150 or so. Can't beat that - I figure I'll save myself at least $1000, which means more cash for my truck!

www.modulemaster.com

[msgross]

great, one more item to watch out for on my Tahoe...

I just replaced the driver side O2 sensor @ 50K miles since it was fouling all four driver side plugs and not the pass side. had to pull the front driveshaft in order to reach the cannon plug, what a PITA..

[Damien]

Looks like you have come a long way. The powder coating on the axles looks great. A word of advice, Do not use a cinder block on its side to support a load. The side is the weakest part of the block.

Originally Posted by msgross

I just replaced the driver side O2 sensor @ 50K miles since it was fouling all four driver side plugs and not the pass side. had to pull the front driveshaft in order to reach the cannon plug, what a PITA..

O2 sensors are emission equipment, as are your spark plugs. I would have taken it to a dealership and have them change it along with the plugs. Emissions equipment is covered under warranty to at least 100k or 10 years by federal law.

[silver7]

According to everything I read it is not a matter of if these go bad, but when. But you probably have quite a few years left before you have to worry about it.

[silver7]

Finished welding my traction bar brackets and drilling holes for the driver side tonight. Everything bolted up perfect!

[msgross]

what do traction bars help with a leaf spring rear? I've seen the 4 link setups with coils but not leafs...

is it simply to keep the axle from rotating?

[silver7]

They are supposed to help with preventing 'axle wrap' or the tendency of the leaf springs to compress when you punch it. The 383 stroker I plan on building should have around 450 HP so I wanted to be sure my lifted springs did not hinder putting power to my rear end.

[msgross]

hope that 12 bolt holds...

[Wildstreak]

Originally Posted by msgross

hope that 12 bolt holds...

x3

great build man looking forward to seeing the end results

[silver7]

Me too.

[Big-Blue]

Where did you get the traction bars? Kit or did you put together the parts yourself?

Looks good! Is it possible to mount to the top of the rear end so that ground clearance isn't an issue?

[silver7]

I bought my traction bars from a guy on Craigslist. I liked these because they were very robust. Now that I know more about them I wish I had made them myself. All you need are 4 x heim joints, 2 x steel rods and 4 x rod ends, a little welding and you are good to go. The brackets were a little more complicated.

I'm sure you could mount on the top, but I preferred the look of keeping mine on the bottom. The bottom part of the diff housing is lower than my traction bar tabs so I wasn't concerned about clearance since it would likely hit first.

Thanks for the comments and questions guys.

[Conroe trucker]

The PO on my truck had mounted them to the same bracket as the leaf spring front mount to. Not bad engineering on his part.

Of course, this truck was maybe making 150HP so what he did not have power for he overcame with speed........

[silver7]

Got some stuff done this week. Finished attaching the 2nd rear traction bar and removed the spare tire cross member.

After a lot of thought and changing my mind multiple times , I finally decided to mount dual shocks in the rear. I was conflicted how to mount them as recommended - one towards the front end - one towards to rear bumper. But as discussed earlier in the thread, this would have put the rear upper shock mount in the way of where I planned to mount my aluminum gas tank. So I decided to mount both towards the front. I considered having them side-by-side, but instead I'm going to have one mounted a little bit further forward of the second so you can see both from the side. Basically, there is a space to the rear of the current bracket where I plan to put it. The brackets I plan on making will be bolt on so if I don't like the look of this I'll have them side by side since my current upper shock bracket could handle this with just a little bit of surgery.

To make this possible I needed to build a lower shock bracket that could handle two shocks side-by-side. You can see where I took a current 1/4" thick shock brackets I bought from Barnes4WD, cut them in half and welded enough 1/4" steel to allow two shocks side-by-side with a bushing in between the two (3.7" inside width).

I hope to finish my other shock bracket today as well as beginning fabrication of the two upper shock brackets.

I also wanted to say thanks to 'Brossow' for a thread he put together back in 2008 which helped me out tremendously with a shock bushing bolt he recommended. I went to NAPA yesterday and picked them up and they worked like a champ. They even came with rubber bushings with the same bolt diameter as my lower shock brackets so I plan to use these in between two two shocks going side-by-side on the same bracket.

All-in-all yesterday was a good day even though my compressor motor died. Does anyone know of a good place to send my motor to be rebuilt? I thought about doing in myself but I need it fast so that won't work.

[msgross]

I like those lower shock mounts, I bought shock tabs but might modify them to look like those.. or just order a set of those...

find an electrical shop in town that might have rebuilt motors, they will probably take yours as a trade in. check the RPM's and direction CW vs CCW and keep your pulley.

[bignbad]

superlift make off road traction bars the mount to the top of the axle houseing to the u-bolts.
http://www.rockymountainsusp.com/tractionbars.htm

here are rear upper shock mount part numbers that i bought to replace mine wornout hacked up home made that was on the truck when i bought the truck.And here is a tread thats has some pictures of them..
http://67-72chevytrucks.com/vboard/s...94#post3069894
15698355 LH
15698356 RH

[silver7]

Bigmike - Good idea. We'll see how much I can get the other motor for and I might end up doing that.

Brossow- My traction bars use the same kind of spherical heim joint as in the picture you posted so yes it will travel with the suspension. I even used the same misalignment spacers on the heim joints under my axle. I guess you missed the earlier photos which showed the my heim joints. That Caltrac bracket is kind of slick - wish I had seen them earlier. . .

bignbad - Thanks. I was looking to see if there upper shock brackets out there I could purchase. Don't mind making them, just takes a lot of time. This helps.

[brossow]

Originally Posted by silver7

Brossow- My traction bars use the same kind of spherical heim joint as in the picture you posted so yes it will travel with the suspension. I even used the same misalignment spacers on the heim joints under my axle. I guess you missed the earlier photos which showed the my heim joints. That Caltrac bracket is kind of slick - wish I had seen them earlier. . .

They will move up and down (and side to side to a negligible extent), but there's no forward and aft motion possible as with the Caltracs. The Heim joints are the same, yes, but there's no front pivot. As a leaf spring compresses, the distance between the spring eyes increases. With the front eye fixed relative to the frame, the center of the spring -- and therefore the axle -- moves rearward. When the spring unloads (as in going over a bump) the spring shortens (eye to eye) and the axle moves forward. Your setup would seem to prevent this movement. Maybe I'm missing something, but I don't think so.

[silver7]

Spot on. I put my traction bars on my truck to limit the movement of my axle forwards and backswards - aka axle wrap. I plan to have close to 500 hp so I was concerned my lifted springs may cause a lot of axle wrap with this kind of horsepower.

I'm curious - if you want front to rear movement in your springs, why did you put traction bars on your truck?

[brossow]

Originally Posted by silver7

Spot on. I put my traction bars on my truck to limit the movement of my axle forwards and backswards - aka axle wrap. I plan to have close to 500 hp so I was concerned my lifted springs may cause a lot of axle wrap with this kind of horsepower.

I'm curious - if you want front to rear movement in your springs, why did you put traction bars on your truck?

I must be missing something. I'll trust you on this for your setup. The more I think about it, essentially what you've done is created a sort of combined trailing arm and leaf spring suspension in one. Sorta.

As for my Caltracs, I'm not preventing fore-aft movement. That's not what a good traction control system does. My goal is the same as what you called it but not what you described: preventing spring (axle) wrap, which isn't fore-aft movement at all but rotation of the axle in place, causing the leaf springs to "wrap" into an S shape. During normal driving the axle still needs to be able to move forward and backward as I described previously and hence the need for the front pivot. Under hard acceleration, however, if the axle tries to rotate forward, the Caltracs prevent this rotation.

But like I said, I'm not an engineer and maybe I'm missing something. I'll leave it at that and hope it perfectly works for you. Sometimes I overthink things.

Cheers,
Brent

[yellow70GMC]

Originally Posted by brossow

I must be missing something. I'll trust you on this for your setup. The more I think about it, essentially what you've done is created a sort of combined trailing arm and leaf spring suspension in one. Sorta.

As for my Caltracs, I'm not preventing fore-aft movement. That's not what a good traction control system does. My goal is the same as what you called it but not what you described: preventing spring (axle) wrap, which isn't fore-aft movement at all but rotation of the axle in place, causing the leaf springs to "wrap" into an S shape. During normal driving the axle still needs to be able to move forward and backward as I described previously and hence the need for the front pivot. Under hard acceleration, however, if the axle tries to rotate forward, the Caltracs prevent this rotation.

But like I said, I'm not an engineer and maybe I'm missing something. I'll leave it at that and hope it perfectly works for you. Sometimes I overthink things.

Cheers,
Brent

He's right, and i'm afraid you're going to break your front mounting points on those bars if you beat on the truck too hard. I hope you don't, though. But yeah "axle-wrap" refers to the axle twisting, not moving forwards and backwards. It needs to move forwards and backwards, that's what the shackle is there for. Brent already described it perfectly. Not tryin to knock your build at all, just my .02 cents. Whether or not my opinion is really worth that much or not is debatable trucks looking great though, can't wait to see more.

[cheepin]

Originally Posted by brossow

I must be missing something. I'll trust you on this for your setup. The more I think about it, essentially what you've done is created a sort of combined trailing arm and leaf spring suspension in one. Sorta.

As for my Caltracs, I'm not preventing fore-aft movement. That's not what a good traction control system does. My goal is the same as what you called it but not what you described: preventing spring (axle) wrap, which isn't fore-aft movement at all but rotation of the axle in place, causing the leaf springs to "wrap" into an S shape. During normal driving the axle still needs to be able to move forward and backward as I described previously and hence the need for the front pivot. Under hard acceleration, however, if the axle tries to rotate forward, the Caltracs prevent this rotation.

But like I said, I'm not an engineer and maybe I'm missing something. I'll leave it at that and hope it perfectly works for you. Sometimes I overthink things.

Cheers,
Brent

Your not missing anything and are correct.In this setup the spring will not be able to articulate.The traction bar will keep it from doing so.
Here's a much better design.Notice it has 2 mounting points are the axle.And a shackle at the frame.This keeps the axle from rotating and lets the springs move.

[msgross]

Silver7, won't your rear springs be as hard as a rock now?