V
vettegirl
Guest
Does anyone have any helpful tips, links, etc. regarding rebuilding the rear end on a 1971?
Thanks!
Thanks!
vettegirl said:
Some clarification may help us to help you.
Many people are referring to the differential when saying, "rear end". You probably are as well, right?
Or, are you talking about everything aft of the doors, including the diff? The spindles? The trailing arms? The transverse spring? The shocks? The u-joints? The brakes? The Emergency brake?
- Thread starter
- #3
V
vettegirl
Guest
Actually, we're rebuilding all of it..
doing a "frame off" resto, but what I have the question about now is the big round thing with the gears inside of it - I guess that's the differential?? (I know, I need to teach my husband to type so he can ask these questions...
)
Thanks!
Lauren
doing a "frame off" resto, but what I have the question about now is the big round thing with the gears inside of it - I guess that's the differential?? (I know, I need to teach my husband to type so he can ask these questions...
)Thanks!
Lauren
As c5d mentioned, this link should help.
http://www.corvettefaq.com/c3/yukon-instructions.pdf
It is generic and the photos reference a non-Corvette (non-IRS) differential, but the theory is the same.
Rebuilding a differential is not for first-timers. If your husband is inexperienced, a trip to a driveline shop would be wise.
Dropping a Corvette differential is difficult, but you did say the body is off. Much easier then. Safety first!!!
http://www.corvettefaq.com/c3/yukon-instructions.pdf
It is generic and the photos reference a non-Corvette (non-IRS) differential, but the theory is the same.
Rebuilding a differential is not for first-timers. If your husband is inexperienced, a trip to a driveline shop would be wise.
Dropping a Corvette differential is difficult, but you did say the body is off. Much easier then. Safety first!!!
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- #5
V
vettegirl
Guest
Don't worry - I won't be doing the work! :eek :eek
My husband is very mechanically inclined (actually a mechanic by trade), but with most things Corvette, after you've struggled with it for hours you find there was a shortcut or a special little trick!
Thanks for the links!
Lauren
My husband is very mechanically inclined (actually a mechanic by trade), but with most things Corvette, after you've struggled with it for hours you find there was a shortcut or a special little trick!
Thanks for the links!
Lauren
- Thread starter
- #6
S
Scott81
Guest
This might be of some help, granted it's an 81 and not a 71 but somewhat similar in how to take it all apart and put it back together. http://www.c3sharktank.com/tech2/rearsusp/rear1.html
Also, the Van Steel suspension video for $20 is well worth it, it won't tell you how to do the bearings or gears/posi unit and isn't a hollywood production but it's a time saver.
Also, the Van Steel suspension video for $20 is well worth it, it won't tell you how to do the bearings or gears/posi unit and isn't a hollywood production but it's a time saver.
- Thread starter
- #7
L
Lucky7's81
Guest
rearend
I have built a few differentials including 69myway's 85 dana 36. I am about to rebuild my diff as well, but first I'm building my 700r4 tranny. That will be done tomorrow and I will then break in the cam on my rebuilt 406. Hopefully I will be driving all day Sunday. I live in FL. If you need help let me know. I live in Jacksonville
phone # 904-908-5432 home
I have built a few differentials including 69myway's 85 dana 36. I am about to rebuild my diff as well, but first I'm building my 700r4 tranny. That will be done tomorrow and I will then break in the cam on my rebuilt 406. Hopefully I will be driving all day Sunday. I live in FL. If you need help let me know. I live in Jacksonville
phone # 904-908-5432 home
GTR1999
Well-known member
You will need several things, which you may already have.
GM Overhaul manual for 1971.
Inch pound Dial torque wrench
Foot pound torque wrench
1" travel dial indicator and mag base
engine stand
Bearing splitter
2 jaw puller
Remove the differential by dropping it out with the crossmember. The diff weights 100 lbs so be careful.
Drain the oil by cracking the cover loose over the edge of a bench.
remove rear cover. Remove the yoke snap rings, if still there and slid out the yokes. You might have to hammer them out if they rolled over the ends.
Stamp the bearing caps so you know where they go back in the same place. These are line honed so don't mix them up. There are also shims in between the carrier bearings and housing. Make sure you keep these marked per side too.
With the bearing caps marked remove them.
The carrier is preloaded so it shuldn't just pull out. If you have a case spreader you can use it to remove the carrier, if not put a box wrench on the ring gear and rotate it until it walks against the housing and causes the carrier to pop out.
Once the carrier is out then use an impact gun to remove the pinion nut and drive out the pinion. Be careful you don't get cut by the teeth.
Clean and paint the stripped housing. I drill and tap the housing for a drain plug too. Not NCRS approved though!
You will have to remove the 4 posi springs to pull out the side gears and posi clutches. "mike" up the clutches to check the wear. Also look at them,you should see the diamond pattern. If the pattern is worn away or you find a broken clutch replace the set. There were 2 types of posi clutches solid rings and later"snowflake" types. The solids are better. I think '71 was around the time they went to the snowflake type to help with posi chatter. They break easier under load. Look at the side gears,called spider gears by some. count the teeth. The small ones should have 10, the large side splined gears could have 16-17-or 18. The 17's are the best. So hopefully you have 10-17's.
You can also count the ring gear teeth and divide the pinion teeth to see exactly which ratio you have.
Follow the manual it will instruct you in the basics. I don't reuse the posi springs,instead I setup using shims to repalce the springs and this seems to work much better. Check th eJune 1979 issuer of Popular Hot Rodding if you can find it somewhere-very good article on settingup posi-tractions.
I'm now tired of typing! This is an outline,there is more to it but if you've worked on other rear ends it shouldn't be that bad to do. If you need a new ring gear I would buy ones made in the USA,like US gear or from Tom's in CA.(US Gear too) some of the vette gears are made outside of the US and sold by distributors in the US. You'll see the difference in price between them.
Post if you have any questions, but I don't stop by here too much.
GM Overhaul manual for 1971.
Inch pound Dial torque wrench
Foot pound torque wrench
1" travel dial indicator and mag base
engine stand
Bearing splitter
2 jaw puller
Remove the differential by dropping it out with the crossmember. The diff weights 100 lbs so be careful.
Drain the oil by cracking the cover loose over the edge of a bench.
remove rear cover. Remove the yoke snap rings, if still there and slid out the yokes. You might have to hammer them out if they rolled over the ends.
Stamp the bearing caps so you know where they go back in the same place. These are line honed so don't mix them up. There are also shims in between the carrier bearings and housing. Make sure you keep these marked per side too.
With the bearing caps marked remove them.
The carrier is preloaded so it shuldn't just pull out. If you have a case spreader you can use it to remove the carrier, if not put a box wrench on the ring gear and rotate it until it walks against the housing and causes the carrier to pop out.
Once the carrier is out then use an impact gun to remove the pinion nut and drive out the pinion. Be careful you don't get cut by the teeth.
Clean and paint the stripped housing. I drill and tap the housing for a drain plug too. Not NCRS approved though!
You will have to remove the 4 posi springs to pull out the side gears and posi clutches. "mike" up the clutches to check the wear. Also look at them,you should see the diamond pattern. If the pattern is worn away or you find a broken clutch replace the set. There were 2 types of posi clutches solid rings and later"snowflake" types. The solids are better. I think '71 was around the time they went to the snowflake type to help with posi chatter. They break easier under load. Look at the side gears,called spider gears by some. count the teeth. The small ones should have 10, the large side splined gears could have 16-17-or 18. The 17's are the best. So hopefully you have 10-17's.
You can also count the ring gear teeth and divide the pinion teeth to see exactly which ratio you have.
Follow the manual it will instruct you in the basics. I don't reuse the posi springs,instead I setup using shims to repalce the springs and this seems to work much better. Check th eJune 1979 issuer of Popular Hot Rodding if you can find it somewhere-very good article on settingup posi-tractions.
I'm now tired of typing! This is an outline,there is more to it but if you've worked on other rear ends it shouldn't be that bad to do. If you need a new ring gear I would buy ones made in the USA,like US gear or from Tom's in CA.(US Gear too) some of the vette gears are made outside of the US and sold by distributors in the US. You'll see the difference in price between them.
Post if you have any questions, but I don't stop by here too much.
Hey Coupeman
You said "Remove the yoke snap rings, if still there and slid out the yokes"
I think one of my snap rings poped off when I was installing my mono-spring.
Do I need to tear the rearend back down and replace it, Or is it common for these things to come off?
You said "Remove the yoke snap rings, if still there and slid out the yokes"
I think one of my snap rings poped off when I was installing my mono-spring.
Do I need to tear the rearend back down and replace it, Or is it common for these things to come off?
GTR1999
Well-known member
Popped off from the rear spring? Not sure we're talking about the same thing but I'll explain the yokes.
The side yokes in the rear differential are held in by snap rings in the inside of the differential. The 1/2 shafts are connected by a Ujoint so the any movement would be outward affecting the rear alignment and handling. The yokes ride up against the positraction spider gear pin(shaft) they are case hardened and someofhte later model 70's yokes were not very well treated and wear much faster. The distance from the end of the yoke to the snap ring grovve in the yoke is approx .187(3/16") Badly worn yokes will wear down to this snap ring and it will fall into the differential. The metal from the wear ends up in the oil and becomes a nice "lapping compound" on your bearings and gears. Some yokes will wear until they move in/out 1/4" The yoke will start to grind agianst the differntial housing when worn too much. I just rebuilt one that was worn down 1/8" to the seal. I was able to reuse the housing because I installed new yokes and rebuilt the posi. This cut down the play to .003".
So if your yokes are pulling out then you may have a problem there and the only way to fix it is to drop the differential.
Hopefully I answered your question,if not let me know.
The side yokes in the rear differential are held in by snap rings in the inside of the differential. The 1/2 shafts are connected by a Ujoint so the any movement would be outward affecting the rear alignment and handling. The yokes ride up against the positraction spider gear pin(shaft) they are case hardened and someofhte later model 70's yokes were not very well treated and wear much faster. The distance from the end of the yoke to the snap ring grovve in the yoke is approx .187(3/16") Badly worn yokes will wear down to this snap ring and it will fall into the differential. The metal from the wear ends up in the oil and becomes a nice "lapping compound" on your bearings and gears. Some yokes will wear until they move in/out 1/4" The yoke will start to grind agianst the differntial housing when worn too much. I just rebuilt one that was worn down 1/8" to the seal. I was able to reuse the housing because I installed new yokes and rebuilt the posi. This cut down the play to .003".
So if your yokes are pulling out then you may have a problem there and the only way to fix it is to drop the differential.
Hopefully I answered your question,if not let me know.
The new rear spring pulled the wheel/ta/half shaft down and the yoke out. But you did answer my question. Looks like I am going to have to remove the spring again and pull the cover of the rear end to remove and replace the yoke clip.
Thanks
Thanks
GTR1999
Well-known member
You can remove the differential by either separating from the cover as in the manuals or (much better) remove the whole thing with the crossmember. Good luck
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