(Another) Forest Living Suburban Build Thread

[justcuz]

Looks like it should work fine. Nice to have the adjustability of the coilover. Do you have to swing the UCA up out of the way to remove the coilover? Will be looking forward to real world trail usage reports. GM converted their vehicles to this type of suspension in 2007 for a few reasons, one for sure was the improvement in the ride. I hope the alignment goes well so we can see some real world testing soon.

How tall is your aftermarket lift spindle between the ball joints? Being a junkyard scrounger I noticed while getting Ford keys a couple weeks ago that Expedition spindles are 16" tall and mount the same as Chevy spindles. Not sure if the ball joints are compatible, but they do use a 3 bolt unit bearing and the drive axles have CV's on both ends.
Having CV joints at both ends of the drive axles will allow a little more angle to accommodate a little lift and the extra droop from the taller spindles. Have to check the inner 6 bolt drive flanges too.

Since the GMT400 has a different shock mount that may not support this coilover option, I am going to do some more research.
Later in the summer, I am going to buy an entire Expedition/F150 front end from the A arms out and see what fits a Chevy.

 

[Martinjmpr]

Since the GMT400 has a different shock mount that may not support this coilover option, I am going to do some more research.

.
I believe the builder (Atomic) said it would work with at least some of the GMT-400 trucks although I don't know which ones.

 

[Burb One]

So did you keep the same amount of lift that you had before? Would be interested in seeing any before/after side views to see how the lift looks.

Same amount of lift as before, almost of the entirety of the Rough Country kit stayed on (diff drop bracket, dropped knuckles, etc.) Only parts that were taken off from the kit were the drop mounts for the torsion bars, and the torsion bars themselves (as well as the shocks obviously).

I will take pictures later this week at the alignment shop.

 

[justcuz]

It would be interesting to find out. I'm sure a substantial weld on bracket/braces could be made, although GMT400 upper control arms are different and that takes away from the DIY bolt on simplicity of the kit.
Lots of potential here for a viable option to torsion bars and keys and IMO better than buying Sway a Ways.
I suspect from a weight standpoint it is lighter also, torsion bars are fairly heavy.

The comment about the cowl shake makes perfect sense, you are no longer transferring suspension forces down the torsion bar to the crossmember behind the cowl. All the suspension forces are now kept in the vicinity of the wheels and tires and ahead of the cowl will give a smoother ride.

There has been a lot of speculation that this transfer of energy is what caused a lot of front door problems with GMT400 vehicles. Suspension induced body flex/harmonics that wore out door hinges and cracked front doors.

 

[Burb One]

Looks like it should work fine. Nice to have the adjustability of the coilover. Do you have to swing the UCA up out of the way to remove the coilover? Will be looking forward to real world trail usage reports. GM converted their vehicles to this type of suspension in 2007 for a few reasons, one for sure was the improvement in the ride. I hope the alignment goes well so we can see some real world testing soon.

How tall is your aftermarket lift spindle between the ball joints? Being a junkyard scrounger I noticed while getting Ford keys a couple weeks ago that Expedition spindles are 16" tall and mount the same as Chevy spindles. Not sure if the ball joints are compatible, but they do use a 3 bolt unit bearing and the drive axles have CV's on both ends.
Having CV joints at both ends of the drive axles will allow a little more angle to accommodate a little lift and the extra droop from the taller spindles. Have to check the inner 6 bolt drive flanges too.

Since the GMT400 has a different shock mount that may not support this coilover option, I am going to do some more research.
Later in the summer, I am going to buy an entire Expedition/F150 front end from the A arms out and see what fits a Chevy.

The UCA does not have to be removed or swung up, I can remove the shock with just the two bolts on the shock mounts(and a little pressure and finagling! Would make for easy spare changes in the field.

I'm not sure about the space between the ball joints, I can measure for you if you want tonight, but I can tell you it's more than 16 inches I believe.

I'm not sure the differences between the GMT400 and GMT800, also not sure how much more reliable the ford CV's will be, I thought their independent stuff was weak? *saying that, you seem to be a DIY'er, so I am sure if the GMT400 mount points are different, modifying these mounts (and either bolting or even welding them) wouldn't be hard at all. Would just be a matter of figuring out where the mounts need to be, modifying/fitting them, and then measuring the distance for the correct spring/ shock.

 

[Burb One]

It would be interesting to find out. I'm sure a substantial weld on bracket/braces could be made, although GMT400 upper control arms are different and that takes away from the DIY bolt on simplicity of the kit.
Lots of potential here for a viable option to torsion bars and keys and IMO better than buying Sway a Ways.
I suspect from a weight standpoint it is lighter also, torsion bars are fairly heavy.

The comment about the cowl shake makes perfect sense, you are no longer transferring suspension forces down the torsion bar to the crossmember behind the cowl. All the suspension forces are now kept in the vicinity of the wheels and tires and ahead of the cowl will give a smoother ride.

There has been a lot of speculation that this transfer of energy is what caused a lot of front door problems with GMT400 vehicles. Suspension induced body flex/harmonics that wore out door hinges and cracked front doors.

You beat me to it, regarding the DIY modificaitons of the mounts, or making your own for your GMT400

Interesting, I didn't think about that with the torsion bars, makes sense. I look forward to the adjust-ability of the coil overs as well I need to load up the truck all the way to weight and set the proper ride height, no more renting that torsion bar tool from autozone anymore!

 

[justcuz]

Not sure how weak it is, looks to be on par with Chevy stuff.
First generation Expedition and F150 had bigger front brakes than GMT400 vehicles.
I found one Expedition with lift spindles that were 20" tall, stock is 16" on first generation and I know Chevy spindles are shorter than that, so if you could, please measure your lift spindles for me.
The later model Expedition with the factory coil over and 6 lug bolt pattern is just a hair off of the Chevy 6 lug pattern.
They have a 20" tall aluminum spindle.

The inner CV can't hurt. When you broke your drive axles was it at the CV or inner tripot joint?
I always thought drive axles with slip joints was the answer, but the off road racing guys are getting enough plunge with CV's at both ends of the drive axles.

 

[Burb One]

Will do on the measuring! Would be an interesting conversion..

Mine broke on the inner tripod joint... The aftermarket axle was the wrong one and was too short, so the tripod/ball was almost all the way out of the housing at regular height, muchh the less droop...

I always thought a slip joint and non-plunging ends, would be stronger, and never understood why manufactures don't use them.

Saying that, at least with these aluminum cased GMT400/800, I think having the CV's as the weak point is a good thing. I can change them in less than 20 minutes, and they are reasonably inexpensive. Much better than other things breaking....

 

[justcuz]

Good point, the drive axles are easier and cheaper than the aluminum front differential.
Your lift kit does not have the drive flange spacers at the front dif?

 

[Burb One]

Good point, the drive axles are easier and cheaper than the aluminum front differential.
Your lift kit does not have the drive flange spacers at the front dif?

If you find a thin enough socket, you can even change them without lifting the truck/ removing the wheel!

Yes the rough country has spacers between the flange and the stock CV. I wish there was an option to have longer CV's instead of the spacer, because it would reduce the angle even more. I read somewhere NNBS CV's are longer and "fit", but some report they are still slightly too short and so are just as weak, even with the slightly better CV angle, because the joint gets pulled out of the tripod. The tripod is the weak point on these CV's.

 

[PGW]

Cool setup! What spring rate did you use for the coil? Depending on your budget JDFab can do custom axles with 930cv inners, not sure how much they are though, you would have to call them. If you just want longer axles I know Branik Motorsports should be able to cut them. If you really want to beef them up, the 2500 outer CV should fit right into the 1500 unit bearing, but you would be on your own on an adapter flange on the diff side.

 

[Burb One]

The coils are PAC 14 inch coils with 650lb springs. We will see if they are heavy enough (Was on the border between 650,675 and 700.
For documentation, I also went with the QA1 D701 Shocks.

Interesting, never thought about having someone cut the stock ones, and adding an extension. If I start having breakage trouble, I might do that. However, I have only broken one, and it was the incorrect size. The OEM's went to 200k+ before the boots started looking haggard.

 

[PGW]

Sorry, I should have used a better term, you wouldn't want to cut and extend, they would make new ones from scratch that would be longer.

 

[Burb One]

Sorry, I should have used a better term, you wouldn't want to cut and extend, they would make new ones from scratch that would be longer.

Got it, well good to know there's some options. We'll see how it all ends up holding up, but like I said this doesn't change the angles at all from what I had before, so it should be just as reliable. Also, having an easily fixed and accessible weak point, is better than making the weak point the diff.

 

[justcuz]

I too heard that the 3/4 ton axles fit the 1/2 ton unit bearing, not sure about length and inner tripot and 6 bolt flange

LCA's on GMT800 3/4 tons are longer than the 1/2 ton and kind have the J arm look to them, so I bet the drive axles are longer and stronger.

Might be worth looking in to...but then we have the aluminum diff, how much can it handle?