Zero Rates,Degree Shims & Pinion Angles

[sponsoredbydad]

Does it make a difference where the degree shim and zero rate sit? (Which on top of which) Did I do this wrong? Whats bugging me is the gap under the zero rate sitting on the perch. It is flat in the front but that gap in the rear . I am thinking it(The Gap) is also messing with the pinion angle. No shims pointed it way down, 4 degree shims pointed it way up, so now these 2 degree shims still point it up a wee bit. I've looked at it so long I can't see past the trees anymore

 

[nvrenuf]

What about the perches themselves, are you sure they're flat? I've seen lots of axles with rounded perches from being in heavily worked or abused trucks.

 

[jt512]

I'm not sure if there is a correct "order" for the shim/zero rate, but the gap is most likely due to the spring pad having collapsed/ worn down essentially from years of use. They should be rounded off on the ends to avoid a "sharp" edge and stress riser problems in the spring itself, but yours looks a little too rounded.
Re-plating the top to make it flat again is not too bad to do, or even just replacing the spring pad altogether is another option.....both would require welding

 

[sponsoredbydad]

What about the perches themselves, are you sure they're flat? I've seen lots of axles with rounded perches from being in heavily worked or abused trucks.

Sure? Absolutely not. Guess I would have to take them apart again to really make sure. Just did not notice the gap untill the degree shim install. I don't think it had the gap with just the zero rate.

 

[sweetk30]

i would prefer in the middle of that mix is best.

and those STAMPED out perches are like stamped rocker arms = TONS of play in fit n function .

the zero rate is flat but as you can see your perches are not .

and fyi to anyone out there with aluminum degree shims provided by most companys these days .

DO NOT INSTALL THEM ON NON SOLID BLOCKS OR PERCHES .

this pic is of a cust of mine on his dodge 3500 just did 5" lift month or so ago. rear springs come with the aluminum shims on them as a complete set and told you to run stock block ( open hollow factory ) and all good. well less than 3k miles later here was his CLUNKING and SHIFTING rear end problem i found .

1/2 of each wedge gone and rest falling out. ubolts loose and axle moving around. non solid surface is what caused them to have severe pressure points and self destruct.

easy fix on his ext cab long bed = remove shims and new ubolts .

 

[dyeager535]

Could be wrong but I assumed the taper on the zero rate should be against the spring, since it mimics the "non-sharp" edge of the stock spring perch.

I was thinking maybe that was so a sharp edge wouldn't act as a break.

May be overthinking it, but I can't imagine another reason to round just one side like that.

 

[AKbigsub]

You are right as far as the rounded edge goes. However, I mounted mine wrong five years ago and they have not broken the springs YET.

 

[K85 Octane]

seems like I would want the centering bolt head to be flat against the zero rate
in the picture, I don't think this is possible with the shim "tilting" the zero rate and making the mounting surfaces not parallel. (surface of bolt head and nut) I would put the shim between the zero rate and axle. I know it's not bolts in but I'd rather the spring pack be as solid as possible. Would seem like not having the surfaces parallel would cause extra stress on the bolt head and possibly pop it off at some point. Dunno

Best thing to do.... degree the zero rate. I sold my standard ones and ordered a 4 degree cut into another set of zero rates from ORD. Good to go. Parallel mounting and solid, no shims

and yes, next time my front axle is out, I'm beefing up the perches. Mine look a little like yours, just not as bad My rear is pretty good, no shims there either.

 

[sponsoredbydad]

I just ordered some new perches from diy4x. Think I will eliminate those shims and just weld those perches so the pinion angle is correct. So pinion angle should be straight as possible correct? Welding on axle tube do I need to drain it & remove axles or can I just leave it complete and weld it that way? (12 Bolt)

 

[jt512]

Pinion angle will depend on driveshaft style (single u joint or cardan joint ), I don't want to tell you specifics as I'm not totally sure, but generally you do need some angle for the u joint to operate properly.

As for welding, I see no need to drain, remove axles etc. You are welding far enough away from the seals.

 

[cybrfire]

The EZ inch should be right under the springs and then the shim underneath of that.

In essence, it is another leaf in the pack. Just a really short one. As mentioned, the radius corners are easier on the leaf springs than a sharp edge. You'll have to be using it pretty hard to notice this benefit but it is there.

Shim under the EZ inch right on top of the perch. With it on the bottom, the center pin can take advantage of the angled counter bore and sit with the head flat in the pocket.

 

[Mastiff]

I thought the zero rate was supposed to bolt to the pack like an extra spring. Then the only option is for the shim to go under that. The slick thing would be to shape the zero rate for the angle you want, or better yet move the perches. Sounds like you'll be doing that anyway.

 

[sponsoredbydad]

Thanks everyone. Guess I put that together wrong But at least I knew enough to think it was not right and ask the brotherhood to steer me in the right direction THANKS again

 

[Blue85]

I think you can order a tapered zero-rate. This is the best option, as the center bolt insert can be counterbored at the correct angle - so the bolt can sit flat. It's also stronger as everything is bolted together. This does cost like 1/4"-1/2" of lift.

If you don't do that, you need the tapered sleeve under the head of the center bolt that matches the angle of the shim. This also lets the bolt go in flat and adds the extra length the bolt head needs to go through the extra thickness of the shim.