I started the rebuild of the Final Drive. If for any reason I am unable to achieve a high quality rebuild, I will send it to Coventry West to see if they can bail me out.
Numbers visible cast in the case are;
C4HU-004-16
F 66 1579
46/13
BP-L
Ring numbers
4HA 016 9A 46X13 STL C66 9FB
8441 serial number
A ‘9’ in a circle (incomplete and illegible).
Thanks to forum member comments, I am setting a baseline before taking the unit apart. Results so far were;
Pinion preload 10 inch pounds.
Backlash .010 thousandths of an inch.
Coast gear tooth contact was evenly spread over the profile and nearer the toe just as specified in the manual.
Drive gear tooth contact was very similar to Coast but maybe centered a little more between the heel and toe.
When the depth micrometer and ground steel stock arrives, I will measure current pinion depth before removing the pinion.
First problem encountered… Need a special 1-13/16 socket or box end wrench to remove locknut for axle bearing removal (see pic)
To remove, and then re-torque that nut I simply clamped the nut securely in the jaws of a vice (so the unit inverted compared to your photo), and then fashioned a lever to mount on the output flange using two of the four bolts. I thought I had a photo, but can’t find it, but hopefully the description is clear enough.
As this particular set up has the nut down inside the housing where you cannot clamp onto it or get a wrench on it. Take a 1 13/16 socket and cut the top off. Then you can put it over the nut and use a pipe wrench to turn. As it is shim adjustable for clearance, finess is not a requirement, only that you can get it loose and tight.
I reckon that’s a very sensible way to go. i have a diff in my shed that I’ve been intending to have a crack at for a while. I’ve never done this before myself but it can’t be that hard.
I agree it cannot be that hard and I admire Kevin for taking it on. I will watch and learn from this thread.
But the cost of getting it wrong is too high for me. I have had that sinking feeling too many times from mistakes where I have had to take something back out.
But having to drop the IRS again and tear it to bits and reassemble it and reinstall?..
I took mine to a shop around 2001 and no leaks or noise ever since.
I do enjoy changing all the fluids including the differential. Feels like I am being nice to the mechanicals!!
Hi Dennis,
The only way the cost can be high is if you don’t confirm that settings are correct before ultimately putting the differential into service. If you stuff something up along the way, all that you will be out is your time and the cost of bearings you may have damaged.
Bill has the attitude with all things mechanical, that, in the most part, a human put whatever the device may be together and that being human makes him somewhat qualified.
The most difficult aspect of refurbishing a differential comes with not having adequate tools to do the job correctly and for a first time repairer, accumulating these tools is what sends them off to seek someone that specializes in the task.
Once you have satisfactory tools, its just a case of attention to detail.
Hey Dennis, I’ve had a couple of these rebuilt over the years, one by IWE rear ends only in Vancouver. Still in the car, no noise no leaks. But I’d found a local guy, Hugh Lundy, who rebuilt 2-3 others for me, a real pro with these, had all the tools…lots of experience. Sadly he died last month and all that old-timie wisdom went with him.
One of the things he did teach me was to check for “bearing rumble”. I get the impression these diffs are hugely UNDER stressed in this application and that if the oil is clean (and hasn’t all leaked out) a change of seals and gaskets may be all that’s needed and then only b/c it’s out of the car to redo the brakes.
Combine that with the average age of people driving these cars and the fact the cars are rarely in daily driver use and I’m kinda not seeing the point of a $2-3,000 rebuild that will last ANOTHER 50-60 years esp’y if it’s quiet. Check the tooth contact re seal and be done.
So next question is where to get the heat resistant output shaft seals
from snowy Kelowna
Mike
That’s exactly what I did. No problems so far. My opinion is that if the old bearings look good and run quiet, don’t change them. Be aware that when setting up used bearings you use a lower preload.
Mike
Too many tools needed and it would be a lot of learning to go through to do it once in my ownership!!!
Dennis
(If you are ever coming to Vancouver, do tell me and let’s meet!)
Success today removing first carrier bearing with zero damage to the original bearing.
Bought harbor freight puller set. Medium puller with brackets from large puller worked. Needed custom grinding on the puller legs and grade 8 bolts. Puller and heat Did not do it. Had to cool the entire differential in the freezer and then heat did the trick.
A 1-1/16 half inch drive socket is what you see in the pic. It fit perfectly when placed upside down.
Puller set was $28 and upgraded nuts and bolts total $4. Cheap bolts that came with the the puller set bent.
Custom grinding took about an hour to get puller legs to fit into the groves in the diff case allowing access to the inner race.
Using screws to fasten wood to the differential allowed me to use bench vise to safely hold the diff while turning puller bolt.
The standard pinion depth according to the manual is 2.625 inches.
My pinion has a +10 stamped on it so it needs to be raised .010 inches above standard for a final Target measurement of 2.635 inches.
When measured today and after subtracting the .25 inches for the mild steel, it measured 2.636 inches. So, it is. 001 high with good grear tooth contact.
On to the removal of the other carrier bearing and disassembly of the differential tomorrow. I hope to be ordering parts on Tuesday.
Second carrier bearing removed with no problems. It needed time in the the freezer followed by heat just like the first one.
Pinion shaft removal no problem. Pressed it out. It had 3 shims, .05, .02, and. 05. Total shim amount is .012.
I found a good way to remove the oil seal as there were no hints in the manual.
First, pull out the soft seal material and remove the metal support ring from behind it. Put the diff case on top of plates from the shop press. Then, place a 2 inch long metal strip in the void space. Use a drift to punch it out. See pics…
This is the method I used to press the pinion outer bearing’s outer race. It allows press removal without risking damage. Will do same for pinion inner bearing’s outer race.
The 1-1/2 inch socket in the pic is 1/2 inch drive.
Cool thing was the .25 x .5 inch mild steel unused portion from MSC works perfectly.
If you did not adopt @Dick_Maury sensible suggestion, you can fairly easily weld your very own 1-3/16" tube spanner (I made one fairly quick with a piece of pipe and little pieces of flat steel on the end
A more crude way is to use a punch on the nut, either pick punch on the flat face, or blunt one on the corners. Clearly that would meet with disapproval from some, but I have got some nasty things undone using this technique.
2 people doing it simultaneously works very well. If you are careful, the piece will not be damaged in a material way
Turns out the size of the lock nut is 1-7/8 inches. I got lucky today. Bought a $33 Harley Davidson mainshaft sprocket wrench and it worked perfectly!!!
