Francis the Tow Pig - 1949 GMC 250 Dually

[Palf70Step]

Been a while since I had checked this thread. The pig looks very polished! Very Nice!!

[OutlawDrifter]

Originally Posted by Palf70Step

Been a while since I had checked this thread. The pig looks very polished! Very Nice!!

Thanks Bill!

[OutlawDrifter]

Well, a whole year without an update...

Oldest son and I took Francis for a run Saturday afternoon. Grabbed some burgers and ice cream after a 100mi or so jaunt. It reminded me I need to add some extra weatherstripping on the driver's side.

I still need to do AC in the cab, but keep dragging my feet, mostly because I don't want to pull the front clip off. It's a poor excuse, but one that keeps me from progressing forward.

[joedoh]

Originally Posted by OutlawDrifter

a poor excuse, but one that keeps me from progressing forward.

thats a good excuse if i heard one!!

100 miles trouble free, thats a great thing

[OutlawDrifter]

Originally Posted by joedoh

thats a good excuse if i heard one!!

100 miles trouble free, thats a great thing

I'm glad you see it my way Russ, makes me feel a little better about it!

That 6.0L/4L80E combo is just happy moving the approx. 3600lbs down the road. At this point, the only thing I would have changed during the build was using a stock style multi-leaf rear spring and drop blocks instead of the Belltech drop leafs. They just aren't enough, even with the half springs I added.

[joedoh]

Originally Posted by OutlawDrifter

I'm glad you see it my way Russ, makes me feel a little better about it!

That 6.0L/4L80E combo is just happy moving the approx. 3600lbs down the road. At this point, the only thing I would have changed during the build was using a stock style multi-leaf rear spring and drop blocks instead of the Belltech drop leafs. They just aren't enough, even with the half springs I added.

get a good monotube shock maybe, like a gabriel.

[OutlawDrifter]

Originally Posted by joedoh

get a good monotube shock maybe, like a gabriel.

I'm currently running air shocks with about 60psi in them.

I still get a lot of axle hop. I may end up having to run a low profile traction bar, or just swap the leafs out.

[lower50's]

How is the ride? Just soft or bouncy?

[OutlawDrifter]

Originally Posted by lower50's

How is the ride? Just soft or bouncy?

Soft for the most most part. I can run more air in the shocks, but then it defeats the purpose of the drop leafs.

I just don't think its enough of a leaf pack for the added weight of my bed.

[Palf70Step]

I think you are correct about the leafs not being enough. That is a good bit of weight to haul (even) empty on that few a springs. In addition the arch is probably wrong for a lowered truck.

[joedoh]

can you get the longer bolt from the s10 pack and put an s10 overload (the flat one) back in?

[OutlawDrifter]

Originally Posted by joedoh

can you get the longer bolt from the s10 pack and put an s10 overload (the flat one) back in?

Possibly, I'm not sure, I'll have to do some investigating.

[lower50's]

Basically the leaf spring controls the weight of the truck (ride height) the shock controls the ride quality. I would try stiffer shocks.

[6DoF]

maybe a Cal-tracks style traction bar, or a ladder bar really. if you are getting too much axle wrap, going stiffer on the spring to correct that will require going past ideal into too stiff a ride. and too soft a shock can also allow hop even with a good anti-wrap bar.

i agree with trying a non air shock, something like the RS9000 or a QA1 that's adjustable. the air shock might not be the right thing.

"springs just support the weight", but having something the increase in load capacity as it compresses can help the suspension tuning too. maybe try one of those ad-on overload leaves that bolt on top of the pack. would allow you an adjustable pre-load too. when tuning dual-rate coil overs, i like to set the dual-rate stop JUST off the slider at ride height. this means any droop is at the soft spring rate, but any compression is under a much higher rate. cornering this acts like a sway bar with the compression side having a stiffer spring than the unloaded side. if your suspension has a little squat under launch, it can also help you be landing in the stiffer rate to control motion.

https://www.summitracing.com/parts/hel-3512

something like the link ... as you tighten the outer u-bolts, you'd change the preload and when it begins to act.

[OutlawDrifter]

Originally Posted by lower50's

Basically the leaf spring controls the weight of the truck (ride height) the shock controls the ride quality. I would try stiffer shocks.

I'll have to pump the air shocks full and see if it makes a difference. The Hellwig half springs I added helped, but I still think it needs more leaf. At 50-60lbs of air pressure, it brings the tail up a little. I had Nitro2 drop shocks on it when I first put it together, wasn't impressed.

Originally Posted by 6DoF

maybe a Cal-tracks style traction bar, or a ladder bar really. if you are getting too much axle wrap, going stiffer on the spring to correct that will require going past ideal into too stiff a ride. and too soft a shock can also allow hop even with a good anti-wrap bar.

i agree with trying a non air shock, something like the RS9000 or a QA1 that's adjustable. the air shock might not be the right thing.

"springs just support the weight", but having something the increase in load capacity as it compresses can help the suspension tuning too. maybe try one of those ad-on overload leaves that bolt on top of the pack. would allow you an adjustable pre-load too. when tuning dual-rate coil overs, i like to set the dual-rate stop JUST off the slider at ride height. this means any droop is at the soft spring rate, but any compression is under a much higher rate. cornering this acts like a sway bar with the compression side having a stiffer spring than the unloaded side. if your suspension has a little squat under launch, it can also help you be landing in the stiffer rate to control motion.

https://www.summitracing.com/parts/hel-3512

something like the link ... as you tighten the outer u-bolts, you'd change the preload and when it begins to act.

It's already got half springs that add preload. That helped, but it's still not right. Due to my ride height I'd have to use something like this for a traction bar:

https://www.summitracing.com/parts/clv-3701


Appreciate the insight and comments guys!

[joedoh]

if your springs are too soft all a stiffer shock will do is foam from oscillating, which will act like no shock at all. shock mounts arent made to take the weight of the truck either, the lowers are single shear. i think you are right that the bed is too much.

I used ride tech leafs on truck #1 7 years ago, they would "duck" when accelerating and I had good kyb monotubes on it by the end. it still rides soft, I stay in touch with the owner.

the reason i suggested the big flat overload is the same reason 6DoF said. because instead of the spring pack bending at the leaf mount/shock mount, the flat overload will eventually make the leaf pack flat, raising the spring rate, stopping the droop.

if you want to try lowering the truck without drop leafs, get a Z85 pack (three arches leafs + overload) and take out the smallest leaf, then set the ride height with blocks and keep your half springs for hop. in fact adding the overload to the air ride leafs will not help hop either.

[lower50's]

DO you have Monroe Max-air shocks? I have had them in the back of my Jeep for years they are a great shock but quite soft, (bouncy) all the air part is for is adding load capacity that I use when I put a trailer on. I had a shock off of a cube van before it was way stiffer. Hope you get it figured out soon.

[OutlawDrifter]

Originally Posted by joedoh

if your springs are too soft all a stiffer shock will do is foam from oscillating, which will act like no shock at all. shock mounts arent made to take the weight of the truck either, the lowers are single shear. i think you are right that the bed is too much.

I used ride tech leafs on truck #1 7 years ago, they would "duck" when accelerating and I had good kyb monotubes on it by the end. it still rides soft, I stay in touch with the owner.

the reason i suggested the big flat overload is the same reason 6DoF said. because instead of the spring pack bending at the leaf mount/shock mount, the flat overload will eventually make the leaf pack flat, raising the spring rate, stopping the droop.

if you want to try lowering the truck without drop leafs, get a Z85 pack (three arches leafs + overload) and take out the smallest leaf, then set the ride height with blocks and keep your half springs for hop. in fact adding the overload to the air ride leafs will not help hop either.

Originally Posted by lower50's

DO you have Monroe Max-air shocks? I have had them in the back of my Jeep for years they are a great shock but quite soft, (bouncy) all the air part is for is adding load capacity that I use when I put a trailer on. I had a shock off of a cube van before it was way stiffer. Hope you get it figured out soon.

I do have the Monroe Max-Air Shocks.


I did some more reading on the topic last night. Seems I'm not the only one to experience this issue with the BT drop leafs. Consensus from the S10 world is the lo-pro Caltec traction bars. Ride height was never the issue, just the fact I can't keep the axle under control when "marking my territory"

So to make the ride how I envision it in my mind, I think going back to a good quality shock, adding the flat overload, and a set of the traction bars will cure what ails my rear suspension.

[OutlawDrifter]

Nothing new on the rear suspension, still considering my options.

Next item of focus was the '49 GMC. The trans pan has been leaking ever so slighty for TOO long. Drained the pan and put a new gasket on, I must have over torqued the OEM unit. After I filled it back up with trans fluid, I set my focus on the front end. The springs have continued to settle and the frame was resting on the front sway bar. When I bought the bare frame, the seller didn't know if it was a 4cyl or 6cyl rig originally. My guess is for a 4cyl at this point. The added weight of the 6.0L/4L80E and the fact the whole rig weighs 500-600lbs more than the frame originally carried, has shown the weak spot in the front springs.

After pulling the sway bar and playing with the suspension, I decided it was time to move up to a heavier coil spring. After much reading I decided to try either the 5662 or 5664 spring. The 5662 has a spring rate of 706lbs and the 5664 is 767lbs. The 5662 is the heaviest factory spring the S10 platform had with a gas engine. The 5664 was used for the short duration of the diesel option. Both springs are also used in 3rd generation F-body's like my Z28. The 5664 apparently is being phased out or is becoming difficult to get, which is okay, I don't need the '49 to handle like my Z28, I want it to ride nicely and have less bounce. I'll probably end up with a 4600 or 5100 Bilstein shock as well. Going to put in an order today for the new 5662 springs, and give them a shot. I'm good with 1-1.5" of lift on the front end, it will still tuck a small amount of tire, and give me the ride height the '49 had sitting on the sway bar.

Once I get the front dialed in, I'll move my focus back to controlling the rear axle better. Then maybe it's time to get the AC put in this Winter, so I can drive it more next Summer....baby steps ya know!

[joedoh]

good choice! welcome back!

[Palf70Step]

[OutlawDrifter]

Originally Posted by joedoh

good choice! welcome back!

Originally Posted by Palf70Step

Thanks guys!

[OutlawDrifter]

I've got the '49 knocked out with the new springs.



It was a bit of a struggle and still had the "S10 lean" after I put in new springs, so I trimmed about 3/5ths of a coil off the passenger side and have it within an 1/8" of being level in the front. The new coils brought it up exactly 1.5". Before I started teh rear of the fender was 5.5" from the ground and sits at 7" now. If it settles 1/4-1/2" more, that would be perfect. Right now with 60lbs of air in the rear shocks it has about a 1/2" rake. It drives and rides awesome now, definitely made a HUGE difference.



The only in process photo I secured:







As it sits now:








PS - Thanks Russ for the info on cutting the bottom of the spring!

[lower50's]

Stance looks great!! Glad it is driving better now.

[OutlawDrifter]

Originally Posted by lower50's

Stance looks great!! Glad it is driving better now.

Thanks!

Still trying to get caught up on your thread, for whatever reason I wasn't getting update notices!