Remove spider gears from rear end and broken locking pin 91 chevy k1500

hoader

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#1
Hello again
It is an ongoing continuous project on a 91 chevy K1500 truck. I need to change bearings and seals - the pinion is loose. I removed a small locking bolt with an 8mm socket and it was 1/2" long. This is my first time in an automotive differential (have done farm tractors) so no alarms were raised. I could not drive that pin holding the beveled gear out of the housing. Then I noticed the locking bolt was about 1/4" too short to even reach this pin. It is a shallow concave slot across the end of the bolt and does not look like a normal torsion break. Any ideas how to remove the rest of the locking bolt? Do you think there are threads left on the remaining portion of the locking bolt? Has anyone heard of this before? In other words, does it happen once in a while or just to me? :-\
Thank you hoader
 

billr

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#2
Ooh, lots of fun here! Nope, never heard of it, just your luck; but I haven't had to tear into many diffs in my life. Before addressing that broken screw, let me ask about the "pinion" bearing issue. Are you talking about the pinion gear that is driven by the drive-shaft, an engages with the big (about 9" diameter) ring gear? If so, then you need to remove the whole differential carrier unit; and I'm guessing you can't do that because you can't get the axles out because you can't get the spider shaft out. Do I understand correctly so far? For the screw, I would drill a hole in the nubbin left in there and use a screw-extractor (Easy Out, or similar). And, for drilling the screw I would drill through the center of the removed piece, then re-install it and use it as a drill-bushing to avoid damaging the threads in the diff carrier.
 
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#3
lucky you.there is no manual for this one im afraid. ive had a few over the years and they are a grade A bi@@h. look at the piece of bolt you have out to see if it is broken at the threads or not.if there are no threads left in the housing ive taken a really strong magnet and weasled it out that way.if you are unlucky enough to have threads left in the housing sometimes you can turn it out with a pick,all the while moving the pin to take tension off the retaining bolt. i even had to blow one out with the cutting torch once.sorry there is no inspirational words on this one.lol.
 

hoader

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#4
Thanks for your instant answers. Billr, you have it right. Al daniels, Were you able to save anything after using a fire wrench? I am not sure how to hold or turn the bit while it is inside the diff. case. Do they make drill bits with u-joints?
 
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#5
yeah,i saved the diff with the cutting torch. i had to cut away bits of the diff pin until i got at the retainer bolt,cut it and pick enough out to get the rest of the pin out.sorry this is not the best description,it just takes a lot of screwing around. if you can get the weight of the pin off the broken bolt sometimes you can get a small pick in there and turn it out if it has threads still. the other way would be to cut enough of the pin out so as to push the axles in and get the half moon retainers out.after the axles have been pulled you can remove the carrier.good luck man.
 

billr

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#6
That's kind of what I am thinking, too, but I would use a die-grinder to cut the spider shaft, not a torch. How about a picture showing where that screw is and what kind of access you have? Maybe that will trigger some kind of bright idea.
 
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#7
take a while to cut thru that baby with a die grinder. i used to save the pins when i put in new for drifts.unfortunately i dont have a pic handy,probably google a generic one.not a lot of space for a die grinder in there either, and always the danger of nicking a spider or side gear.
 
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#8
A disclaimer first. I do NOT Recommend this method to remove broken pin bolts but I have seen it work many times. It was taught to me by a old school mechanic who was about 60 at the time and had been employed by Mopar and GM dealerships since he got out of high school.
I was two years out of school when I broke off my first cross pin bolt So I went to the old man. Surely Jim will know what to do. He took one look, Walked back to his tool box got A big drift punch and a 10# sledge. Turned the bolt end of the pin to the front side of the rear end put the punch on the other end and told me to hold it there. You have probably figured out what comes next. He blasts the end of the punch HARD shearing the broken bolt in three pieces slides out the pin, removes the spiders. The broken bolt came out no problem after the pin was out.
I have used this method every time I have encountered this problem in the 25 years since then. Only one time did the carrier blow out instead of the bolt shearing. Jim said I didn’t hit it hard enough then shook his head and said “Kids in the shop” as he walked away.
 
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#10
If you drill a hole in the right spot, you might be able to punch/spin it back out of the hole with a small pointy centerpunch.

On some carriers, the hole goes all the way through. Most don't.
 
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#11
Yes it not that uncommon for this bolt to break. Rec you use a lefthand drill bit it will usually come out that way. Or you can use a very long 1/8" drill bit to drill into pin then using an easy out to take out bolt . I havent had to take a torch to one yet but never say never. There is a kit for it Number DPK-01 I have one and have used it. Its not perfect but it works. HTH Greasemonkey :)
 

billr

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#12
And, yes, there are small right-angle drills and flexible drill extenders that may be able to get in there; not easily, but nothing we have been talking about so far is easy.
 

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#13
Brace yourselves, I took Danica's suggestion and although it chipped one side of the carrier, it did work. I got the pinion shaft out and cut my finger on one of the splines. It looked just from from the back but that was just an illusion. The pinion has 12:41 stamped on it. I hope they are common! Last year I noticed the right rear wheel would growl when I rotated it. I figure it was a wheel bearing. I removed the axles and saw huge rollers for bearings. I was expecting needles about 1/8" thick - these are almost 1/2" in diameter. The needles look ok. I'm going to spray solvent to clean up both bearings. How do I decide what is good enough? How much play is allowable? Thanks hoader
 
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#14
dont count out that bearing just yet.what does the axle surface look like where it rides on the bearing?use prussian blue dye on the pinion shaft and crown gear and see what kind of pattern you have.also check pinion to crown play. i havent replaced near as many crown and pinions as i have wheel bearings and axles.
 

billr

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#15
Which bearings are the worry? This threaded started with the pinion bearings being loose, if axles were removed only so that diff carrier could be removed for pinion bearing work, then don't worry about the axle bearings. Do worry about why the pinion bearings are loose, those usually last longer than most everything else on a vehicle.