derekf.com

19 Jan 2020
Differential Part 2

I'll spare y'all - and myself - the trouble of reading (and writing) a bunch of commentary on the gear pattern marking compound and what it shows.

Suffice it to say, .195/.180 was the answer. Backlash is the .008 suggested.

With the new shim kit and the appropriate shims installed, I still have almost an inch of shims (and that's not even counting the two original shims I pulled out!)

So a learning thing - if you use a 1.5" pipe to press the pinion bearing on... make sure you are not also pressing the pipe on! I had to use the bearing splitter to press the pipe back off.. may have been harder to do than pressing the bearing. All good though, no scuffing evident (and it wasn't on a wear surface anyway)

New rear spring. More on this later.

So with the pinion in place (and front bearing, and crush sleeve, and pinion seal), next step is to snug the pinion nut on to get the bearings to their races.

It won't get that far. It won't go any further than e about .040 shy of putting the front bearing on its race (measured by fore-aft movement)

Stalls with about two threads showing.

What's going on? Am I out of thread (is the washer too thick? Too thin? Threads boogered?)

Washer .235, respectable.

Maybe the impact wrench isn't up to the task.

Off to Lowe's, bought the 750 lb-ft version.

No difference.

Returned that, bought the *1000* lb-ft impact.

That worked.

First try, rotating torque right at 15 lbs. Good enough!

I put some paint on the undercarriage where the axle's going to be (conveniently, the last couple of days where it was warm enough to shoot paint) <<

Woo! Time to put this thing in.

Bolts aren't even all the way through, just enough to hold it in place. Still needed to install the axle bearings and seals (also, the Jegs/Summit rear axle rebuild kit didn't come with axle bearings and seals, which was a surprise)

With the new springs, it seems like it's going to ride VERY low (which in general I'm okay with)

This is with the axle jacked up until it started to carry some of the weight.

Measured from the wheelwell edge to the center cap: about ten inches (sorry, camera got in a wierd mode amd ate the important part of the image)

To contrast, if I put the old stock springs back in, that's about 14 inches to the cap -- a four inch drop.

With the stock springs.

Brake bracket test fit. Forward and down seems incorrect.

Also the brake rotor wouldn't fit over the axle center flange.

Tried both of the rotors I had. Oddly - not pictured - it fit over the flange on the pass side just fine.

Moved the caliper to the back by swapping sides. This looks more visually appealling to me, although I'd have thought it'd be higher on the rotor (maybe about 2 o'clock instead of the 4 it is)

Can see the caliper through the wheel.

An issue though: The parking brake lever is going to bounce off the post the shock mounts to.

(alternate view)

Looks like the caliper will have to be on the front end after all. Need to research and see if anyone else is putting these calipers on an A-body.

The AC box was "done", for certain values of "done". When I put it together to prepare to start cleaning it up though, I found that on the bottom, the trailing edge wasn't flush on both halves - one side was offset by about an eighth to a quarter of an inch. So - a pie cut, and start fiberglassing that too.

Moved on to the poly body bushings. They don't photograph well, so you get this image of the 50 year old stock bushings instead. I've got five done, of - what - 16?

Back to the springs. I have strong concerns here. The springs are not well held in place and I suspect will fall out if the suspension ever enters droop.

My notes indicate that these springs (150lb) were ordered after consultation with Dennis on the pro-touring board (... back in 2005) but I have no context for the discussion and can't find it in forum nor PMs (nor archived emails).

I tried to send Dennis a PM but he's not logged on in the past 5 years and not posted in the last decade.

Either the answer will be spring adjusters like in the front (and *something* to keep the springs from falling out) or I'll be getting stock-ish springs instead.

Ain't got to decide today, which is good, since I'm not.

The nice part is that I'm essentially done with the diff (reckon I'd better knock on wood after that statement). Still need to move the calipers again, and run the brake lines, but then I should be able to put in the C-clips and close it up.

Go back to the previous day (3 Jan 2020)

	I'll spare y'all - and myself - the trouble of reading (and writing) a bunch of commentary on the gear pattern marking compound and what it shows. Suffice it to say, .195/.180 was the answer. Backlash is the .008 suggested.
With the new shim kit and the appropriate shims installed, I still have almost an inch of shims (and that's not even counting the two original shims I pulled out!)
	So a learning thing - if you use a 1.5" pipe to press the pinion bearing on... make sure you are not also pressing the pipe on! I had to use the bearing splitter to press the pipe back off.. may have been harder to do than pressing the bearing. All good though, no scuffing evident (and it wasn't on a wear surface anyway)
New rear spring. More on this later.
	So with the pinion in place (and front bearing, and crush sleeve, and pinion seal), next step is to snug the pinion nut on to get the bearings to their races. It won't get that far. It won't go any further than e about .040 shy of putting the front bearing on its race (measured by fore-aft movement)
Stalls with about two threads showing. What's going on? Am I out of thread (is the washer too thick? Too thin? Threads boogered?)
	Washer .235, respectable.
Maybe the impact wrench isn't up to the task. Off to Lowe's, bought the 750 lb-ft version. No difference. Returned that, bought the 1000 lb-ft impact. That worked.
	First try, rotating torque right at 15 lbs. Good enough!
I put some paint on the undercarriage where the axle's going to be (conveniently, the last couple of days where it was warm enough to shoot paint)	<<
	Woo! Time to put this thing in.
Bolts aren't even all the way through, just enough to hold it in place. Still needed to install the axle bearings and seals (also, the Jegs/Summit rear axle rebuild kit didn't come with axle bearings and seals, which was a surprise)
	With the new springs, it seems like it's going to ride VERY low (which in general I'm okay with)
This is with the axle jacked up until it started to carry some of the weight.
	Measured from the wheelwell edge to the center cap: about ten inches (sorry, camera got in a wierd mode amd ate the important part of the image)
To contrast, if I put the old stock springs back in, that's about 14 inches to the cap -- a four inch drop.
	With the stock springs.
Brake bracket test fit. Forward and down seems incorrect.
	Also the brake rotor wouldn't fit over the axle center flange.
Tried both of the rotors I had. Oddly - not pictured - it fit over the flange on the pass side just fine.
	Moved the caliper to the back by swapping sides. This looks more visually appealling to me, although I'd have thought it'd be higher on the rotor (maybe about 2 o'clock instead of the 4 it is)
Can see the caliper through the wheel.
	An issue though: The parking brake lever is going to bounce off the post the shock mounts to.
(alternate view) Looks like the caliper will have to be on the front end after all. Need to research and see if anyone else is putting these calipers on an A-body.
	The AC box was "done", for certain values of "done". When I put it together to prepare to start cleaning it up though, I found that on the bottom, the trailing edge wasn't flush on both halves - one side was offset by about an eighth to a quarter of an inch. So - a pie cut, and start fiberglassing that too.
Moved on to the poly body bushings. They don't photograph well, so you get this image of the 50 year old stock bushings instead. I've got five done, of - what - 16?
	Back to the springs. I have strong concerns here. The springs are not well held in place and I suspect will fall out if the suspension ever enters droop. My notes indicate that these springs (150lb) were ordered after consultation with Dennis on the pro-touring board (... back in 2005) but I have no context for the discussion and can't find it in forum nor PMs (nor archived emails). I tried to send Dennis a PM but he's not logged on in the past 5 years and not posted in the last decade. Either the answer will be spring adjusters like in the front (and something to keep the springs from falling out) or I'll be getting stock-ish springs instead. Ain't got to decide today, which is good, since I'm not.