14 bolt 454 1991 differential ID question again

[1998_K1500_Sub]

I already sanded and primed the housing except the area where the spring perch welds
thanks

Will you be able to locate the spring perches properly so as to provide the correct pinion angle?

(edit) Those perches are also angled w.r.t. the axle tube, see my next post about the anchor plates.

 

[1998_K1500_Sub]

The leaf spring anchor plates have a "LH" and "RH" distinction on the GMT400, I learned today.

Why is this?

Viewed from the top of the truck (bird's eye), the leaf springs are further apart at the front and closer together at the back, like this:

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The spring perches welded atop the axle tubes match the angle of the springs; this is obvious if one looks closely. I noticed this, today.

AS SUCH, the leaf spring anchor plates are unique for each side, "LH" and "RH".

The part numbers for the various plates are:

3/4ton and SRW 1ton
15592588 RH side (RA has stock)
15592587 LH side (discont'd)


DRW 1ton
15592590 RH side, dual wheels (discont'd)
15592589 LH side, dual wheels (discont'd)


1/2ton
15592586 RH side 1/2 ton (RA has stock)
15592585 LH side 1/2 ton (discont'd)

The "RH" C/K2500-3500 leaf spring anchor plates, if you choose to use them, are available new on RockAuto for about $18/ea.

I bought the "RH" plates the other day and have confirmed fitment on my 9.5” 3.375"OD axle tubes. Their bolt holes accommodate the threads on a 5/8” U-bolt.

I may be able to make the "RH" plate work on the "LH" side. The issue is that the bolt holes in the anchor plate don't line up well with the U-bolts on the springs, because springs cause the U-bolts to be angled "one way", and they in turn fit around the (also angled) spring perch, but the bolt holes in the “RH” anchor plate are angled the "opposite" way… so the fitment looks “tight” or maybe impossible.

Those for C/K1500 fit, I assume, the 8.5" with 3.125" OD tubes.

BE ADVISED, some third-parties are selling "universal" anchor plates which try to side-step the "LH" and "RH" distinction by mis-shaping the anchor plate so that it doesn't tightly cradle the axle tubes. I bought a pair of these for $80 and wasn't impressed, they really didn't support the axle tubes in the way GM intended. I have no intention of using them.

An alternative solution seems to be the U-bolt flip kit, but I haven't yet bought and studied one. A lot of guys have used them but that doesn't mean there aren't "good" and "poor" kits out there.

As for the GM originals, I'm guessing the "LH" side plates were often replaced because of salt / rust. Hence, "LH" plates are no longer available while the "RH" plates remain in stock.

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[454cid]

I wonder if a newer truck part would work, or if the spring angles and tube diameters are different.

 

[someotherguy]

The leaf spring anchor plates have a "LH" and "RH" distinction on the GMT400, I learned today.

Why is this?

Viewed from the top of the truck (bird's eye), the leaf springs are further apart at the back and closer together at the front, like this:

You must be registered for see images attach

The spring perches welded atop the axle tubes match the angle of the springs; this is obvious if one looks closely.

AS SUCH, the leaf spring anchor plates are unique for each side, "LH" and "RH".

The part numbers for the various plates are:

3/4ton and SRW 1ton
15592588 RH side (RA has stock)
15592587 LH side (discont'd)


DRW 1ton
15592590 RH side, dual wheels (discont'd)
15592589 LH side, dual wheels (discont'd)


1/2ton
15592586 RH side 1/2 ton (RA has stock)
15592585 LH side 1/2 ton (discont'd)

Only the "RH" C/K2500-3500 leaf spring anchor plates, if you choose to use them, are available new on RockAuto for about $18/ea.

I bought the "RH" plates the other day and have confirmed fitment on my 9.5” 3.375"OD axle tubes. Their bolt holes accommodate the threads on a 5/8” U-bolt.

I may be able to make the "RH" plate work on the "LH" side. The issue is that the bolt holes in the anchor plate don't line up well with the U-bolts on the springs, because springs cause the U-bolts to be angled "one way" while the bolt holes in the anchor plate are angled the "opposite" way.

Those for C/K1500 fit, I assume, the 8.5" with 3.125" OD tubes.

BE ADVISED, some third-parties are selling "universal" anchor plates which try to side-step the "LH" and "RH" distinction by mis-shaping the anchor plate so that it doesn't tightly cradle the axle tubes. I bought a pair of these for $80 and wasn't impressed, they really didn't support the axle tubes in the way GM intended. I have no intention of using them.

An alternative solution seems to be the U-bolt flip kit, but I haven't yet bought and studied one. A lot of guys have used them but that doesn't mean there aren't "good" and "poor" kits out there.

As for the GM originals, I'm guessing the "LH" side plates were often replaced b/c of salt / rust. Hence, "LH" plates are no longer available while the "RH" plates remain in stock.

You must be registered for see images attach

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Great info and something I would have never caught, since my adventures with replacing U-bolts has generally involved doing an axle flip kit which means new bolts and plates. And other than putting the leaf pack under the axle vs. over, the hardware is very similar with the U-bolt flip kit. No more worries about LH vs. RH.

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Richard

 

[1998_K1500_Sub]

I wonder if a newer truck part would work, or if the spring angles and tub diameters are different.

I’ve wondered the same thing.

I have no answers, yet.

 

[1998_K1500_Sub]

Here’s a picture of the new GM “RH” anchor plate for a 3.375” axle tube (9.5” & 10.5”), one of the two I bought from RockAuto.

Note the ”RH” (right-hand) and the part number stamped into the plate. This is what tipped me off that there might be some “side-edness” to these.

I will try to take some pictures today that illustrate the challenge of using a right-hand “RH” plate on the left-hand “LH” side.

 

[1998_K1500_Sub]

OK, this illustrates the issue.

I have the rear end lying upside down on a set of steel sawhorses. The top member of the sawhorses is approximately aligned with the spring perch on each side.

The right side bracket is pictured first. If you sight down the center of the bracket it seems to align well with the top member of the sawhorse, which is more or less aligned with the spring perch. The U-bolts seem to line up well.

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Here is the left side of the rear end, using a “right side“ bracket. As before, the sawhorse is lined up with the spring perch, more or less.

Sighting down the center of the bracket, it’s a little bit misaligned with the top member of the sawhorse. This is to be expected, since this is the wrong bracket for the left side. Correspondingly, the U-bolts are cocked, one way then the other.

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Notice that those U-bolts aren’t wrapped around a leaf spring, yet. If they were, they wouldn’t be so easy to warp to one side. I think fitment is going to be an issue unless I modify that “RH” bracket for the left hand side, or come up with a different approach.

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[1998_K1500_Sub]

@Schurkey et al., would you please comment on this.

These pictures are one axle on my 9.5”.

The visible double groove is where the seal lips ride.

Express your concern or satisfaction with the condition of the axle there, as best you can glean from the pictures.

If I run a dental pick across those areas, they don’t grab much, only ever so slightly, as though the “groove” is just “rougher than the area around it” and not truly a recessed groove.

I’ve polished it up with 1000 grit sandpaper as best I can, “wet sanding” it so to speak with WD-40.

 

[Schurkey]

Too far gone for a conventional seal to work properly. Too far gone for the bearing, too.

The proper solution is to get a new axle shaft--or two. The band-aid solution is to get "Axle-Saver" bearing/seal combination assemblies for one or both sides depending on the condition of the other axle shaft.

Given that the shaft is not deeply grooved--merely pitted--the Axle Saver bearing could be a reasonable solution. Deeply-grooved axle shafts can be saved temporarily, and for light-duty service at best because the groove is a stress riser that causes axle shaft breakage.

 

[1998_K1500_Sub]

Too far gone for a conventional seal to work properly. Too far gone for the bearing, too.

@Schurkey, I appreciate your comments.

Take a look please, here's a broader view of the same axle, i.e., LEFT axle, PRIOR to wet-sanding the seal contact area. The seal contact area is highlighted:

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The RIGHT axle is in better condition.

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