leaf springs - what weight rating?

[Nelsonpharmd]

Hi everyone,

I have my restoration journal going here: https://www.aviontrailers.net/viewtopic ... 1c1c#p8457

I've been working on the suspension for the last couple of days and I'm ready to order the leaf springs and need some advice. I have an 86' 30P which has a listed weight of about 6000 lbs on the old Avion brochures. With that being said, what weight rating should I get for the leaf springs?

etrailer has the 4-leaf versions in 4500 lbs, 5000 lbs, and 6000 lbs configurations. Obviously that's per axle, so what would you guys recommend? I was debating going the 5000 ls route since that would be 10000 lbs total (two axles). Is that too close or should I push it to the 12000 level and get two 6000 lbs sets? Don't want the suspension to be too stiff...

So, I'm leaning at two sets of 5000 lbs springs. Agree or disagree?

Thanks!

[Razorback]

I am not sure how to answer that..... Are there any legible markings on the existing leaf springs??

I hate to keep saying this, but Chuck Cayo would know the answer to that question.

[Nelsonpharmd]

I wish there were! Ultimately, I went with the 4 leaf 5000 lbs leaf springs. The axles are 5200 each, so I figured to match it up with 5000 lbs springs. I tried calling Chuck but it went to VM. I know he's a busy guy and I don't want to hold up this project too much.

I ended up ordering the pivot bushings the other night, but I was bummed to see that the estimated ship date isn't until the end of April! I'm debating on just leaving them as they are, but as you can see from the pictures below, they look pretty shot. I'm guessing the majority of people haven't changed theirs?

[silverloaf]

You will be fine with the 5000# springs. Generally speaking, it's the number of leaves and and the distance between the pivot points that defines the load.. I believe mine were rated around 5200#.

I'm probably in the minority of those who replaced the bushings. I believe I mentioned this to you in a previous post. I did a considerable amount of suspension work in my younger days. My theory is I can afford to use the replace parts because I work cheap.

During our restoration, I removed the 4 half-shafts. It was a PITA to remove where the shafts connected to the pivot brackets. In the process, I found the shims biased in the wrong orientation. This affected tire wear.

Use the time waiting for the bushings to get the half-shafts, spindles, support brackets, fasteners. etc. evaluated and prepped. Have the spindles evaluated for concentricity and wear. Have the old bushings removed and paint the shafts with rusty-metal primer. When the bushings arrive, it becomes a matter of pressing them in place.

Shims are used at the center pivot points. Their indexing will define the camber setting for the tires. Send me a note and I'll describe the method used by Avion to set the camber.

[Nelsonpharmd]

Thanks Bob!

I'll be honest, I went out there yesterday and loosened the bolt holding one of the half axles in, and it surprisingly slid right out. What didn't move (at all) was the axle pivot point and the shims once I took the bolt out. It looks like they are in there really tight. What worries me is that I'll be able to remove everthing but then getting it all back in will be really difficult.

What was your experience like? Was it hard to put the half axle back in with the new bushing and the appropriate number of shims? Was it a really tight fit?

[Bobbyz]

Those bolts aren't going to come out easy! With the nuts off can you turn the bolts? I'd put an impact on them and get them turning, while hosing them down with your favorite penetrating oil. Not uncommon to need a cutting torch for this sort of thing, mostly for heat. Propane torch won't do it.
HOWEVER YOU RUN THE RISK OFF SETTING THE RUBBER BUSHINGS ON FIRE ! Avions don't hold up well to fire, trust me! I'd only use heat as an absolute last resort, by then you won't care if it burns.

[Bobbyz]

[Bobbyz]

Some info from the1983 owners manual. The toe in adjustment is explained as well as how to support the axle to get the bolt out.

[Razorback]

@Bobbyz , thank you for posting that. I used that process on our 34W shortly after we brought it home. Tire wear was obvious, and on at least one wheel/tire, you could eyeball it and see it was not in good alignment. Our suspension was not as "weathered" as the pictures earlier in this thread so that pivot bushing, washers, and bolt came out relatively easily.

[silverloaf]

Thanks Bob!

I'll be honest, I went out there yesterday and loosened the bolt holding one of the half axles in, and it surprisingly slid right out. What didn't move (at all) was the axle pivot point and the shims once I took the bolt out. It looks like they are in there really tight. What worries me is that I'll be able to remove everthing but then getting it all back in will be really difficult.

What was your experience like? Was it hard to put the half axle back in with the new bushing and the appropriate number of shims? Was it a really tight fit?

The key is to remove all the surface rust from the inside of the brackets, the shims and the bushing’s steel carrier, I lubed mine with white grease before reinstalling. You will feel some resistance when installing the last shim or two into position.

If unable to forcibly insert the last shim(s), remove the assembly and enlarge the bracket width slightly with sledgehammer. After the assembly is in place, the bolt and nut will pull the bracket squarely to its original width.I believe the bolt torque setting is 125 lb-ft.
IF replacing the bushing, it is important to install it to its factory depth. A change in depth could affect the toe-in indexing when everything is put back together.