Early or late rear end - and how to figure out if its any good

apassens · 03-17-2005

I put a replacement rear end into my 71 Gt - Thanks for the donation Bill! - and now 8 month later its leaking at the housing connection between differential and passenger side shaft.

But I found a new donor part already.

Very rusty...after two hours banging and working it didn't make the brakedrums come off yet...

I want to find out is my "new rear end" an early or late model rear end to get the right bearings and restore the whole thing to a decent condition to match the rest of the beloved. The other thing I need to find out is how to identify the integrity of this piece of neglected car history in the first place. The control arm was badly bend - as if someone drag the whole rear end out of the poor car.
Somehow I want to ensure to connect this piece safely.

How do I visually identify early and late rear ends to order the right bearings for restoration.
Is it recommeded to test the donor parts condition to determine use (if so how) or would you recommend to just hold off on a suspect of mistreatment and look for a more promising donor?
Or can the one leaking be repaired - if so how?

nobody · 03-17-2005

There is a variation in the air breather late to early models.Later models had a plastic cap. There is also a variation in axle bearings, later used a roller bearing and the early used a axle type.

tomking · 03-17-2005

I believe you can tell earlier from later models by looking at the backplate which the brake shield bolts up against. The later models are square in appearance while the earlier models have the lower two bolt holes closer together than the upper two bolt holes. Opel gods will confirm or correct.

jlthunder · 03-17-2005

If you are leaking oil and the rear is running fine, you can replace the outer seals and bearings for approx 125.00, if you have the new style rear. The parts are available from OGTS and I had a machine shop remove and install the new bearings for 50.00.

To remove the axles, while still in the car, put the axle on jackstands, remove the rear brakes, remove the 4 nuts on the backplate. You can then pull on the axle and it might just pop out. If it doesn't you can use a slide hammer and attach it to the lugs and pop it out. I didn't have a slide hammer so I inverted the brake drum, put 2 lug nuts on a few turns and used this as my slide hammer. After 2 bangs with the drum, the axle popped right out. Keep an eye out for any shims in the bearing casing.

Are you sure it is gear oil you are seeing and not brake fluid? The rear cylinders do leak when they get old..

RallyBob · 03-17-2005

Originally Posted by jlthunder

If you are leaking oil and the rear is running fine, you can replace the outer seals and bearings for approx 125.00, if you have the new style rear. The parts are available from OGTS and I had a machine shop remove and install the new bearings for 50.00.

To remove the axles, while still in the car, put the axle on jackstands, remove the rear brakes, remove the 4 nuts on the backplate. You can then pull on the axle and it might just pop out. If it doesn't you can use a slide hammer and attach it to the lugs and pop it out. I didn't have a slide hammer so I inverted the brake drum, put 2 lug nuts on a few turns and used this as my slide hammer. After 2 bangs with the drum, the axle popped right out. Keep an eye out for any shims in the bearing casing.

Keep in mind this holds true for the '71-'73 GT rear axles, but not the earlier ones. Early axles have no outer bearing availability (although seals are available), and removing the early axles from the diff. housing requires the removal of the diff. cover to take out the c-clips which physically hold the axles in place.

Bob

hrcollinsjr · 03-17-2005

The slide hammer I used was similar to reversing the drum except I used a bigger hammer, the wheel/tire. It takes very little effort.

Early model axles used a folder lever on the e brake shoe and a ball on the cable end

Late model axles used a hooked lever on the e brake shoe and an eye on the cable end

Harold

apassens · 03-17-2005

Thanks!
So I checked it and the replacement axle is a late model.
I am sure the leaking one is not leaking brakefluid. Its wet were axleshaft housing and differential housing meet. Not at the end seals or below the brake fluid devider etc. So I better get the old thing fixed up...

Guess my weekend plans were just determined.
Thanks Y'all.
Andreas

jeff denton · 03-17-2005

The damage to your rear end is kind of strange, I've seen it happen only once and that was in a Chevy half ton pickup which was used as a one-ton (firewood truck...).
Hey guys, does this really happen to Opels?
Once when I took my S10 to the tire shop for new snow tires I specified it had to be jacked up one side at a time because of the big road chest toolbox bolted into the bed, (once two big guys tried to load it there and couldn't). Sure enough, as I watched from the waiting room a dork slammed a floor jack under the center of the differential and started pumping.
I got him stopped and made him do it right. That would have broken the tubes loose from the center housing for sure!
That's the only way I can imagine this happening, but even on a little GT?
Anyway, before the aforementioned slide hammer trick to get the axles out I definitely would double check something. Pop the cover off and see if there is a little snap ring on the inner end of the axle, between the side gears and the centering pin. Just to make sure you have the later axle and to avoid breaking something if you don't!

I've had both styles apart now and that's the only way I'd trust myself...
What Bob called a "c-clip" is what I refer to as the "little snap ring", extremely inferior to the way chevy's do it with a "c-clip". This is what scares me about using the early rear end in my race car...

hrcollinsjr · 03-17-2005

Don't use the early rear end in your race car. I've seen an axle come out in the same turn, TWICE! We packed it up and watched the rest of the racing that day.

Harold

jeff denton · 03-18-2005

Right. Thanks to Darin (Rallye73) I have a later rear end, disassembled and ready for the 4.22 gears thanks to Stan Czacki!
So we're on track, hopefully, in the differential department...

Killer Texas GT · 03-18-2005

Also from experience, it is no fun to be sitting on the side of the road because the 'C' clip broke leaving the axle, wheel and brake drum lying beside your car. Especially when you where going 70 mph on a clover leaf entrance to the highway (yellow speed sign said 25 mph) and the axle is knocking on your passenger door, while your wife slaps the sh_t out of you, the rear of the car drops as if you blew a tire, while pulling off to the side of the road your rear wheel passes you, and as she screams in your deaf ear, "I will never ride with you again in this GT". That was at least 5 years ago and I still have to beg her to go for a ride in the GT. I no longer run the early rear end for that reason, late model or Impulse rearend is the way for now.
rk

jeff denton · 03-19-2005

Wow. Every time I look at that early style I just wonder what those Germans were thinking! And we gotta quit calling the retainer a "C-clip". It's just a regular old external snap ring. The "C-clip" method is what you see in a Chevy, and I've never seen one fail yet. Of all methods, I like the Ford style, or in Opel terms, "later axle" because you can change a bent axle without pulling the cover, dealing with gear oil and sealant... wanna guess how many times a season I have to help somebody change a bent axle at the racetrack?
As if you could bend an Opel axle. Everybody who sees mine is shocked at the diameter of the axle shaft! I don't think a one-ton has a bigger shaft...
Has anyone ever bent an axle in a GT?
Back to the topic of this thread, I was looking at my bare (later) housing, and it appears the tubes must be hot/cold shrink fitted into the center housing and then plug welded. I wonder how Andreas tube came loose and started leaking?

RallyBob · 03-19-2005

Originally Posted by jeff denton

Has anyone ever bent an axle in a GT?

Not the axles, but the flanges. Gotta carrry a spare, circle-track warfare can be harsh. It's always from car-to-car contact, althouhg we once tagged the wall and tweaked an axle too.

On another note, I know of people who've broken the axles at the flange. They're not one-piece axles you know, the axle shafts are actually fusion welded to the hub (like an OEM valve).

Sorry about the 'c-clip' misnomer, it's basically a Chevy thing, I know! But I've seen plenty of those let go in roundy-round cars too. The clip breaks, and the wheel/tire/axle/brake drum comes out of the diff!

Bob

GTJIM · 03-19-2005

Originally Posted by jeff denton

Wow. Back to the topic of this thread, I was looking at my bare (later) housing, and it appears the tubes must be hot/cold shrink fitted into the center housing and then plug welded. I wonder how Andreas tube came loose and started leaking?

He must have been carrying 1/2 a tonne of firewood in the back of his GT!

Perhaps a good cleanup with Acetone or Laquer thinners then an application of Loctie (TM) - one of the grades that "wicks in" to small spaces - might fix the leak. Cover that with a brush load of an oil based paint to be sure.

Chevy 10 & 12 bolt diffs have aftermarket "C"-clip eliminator kits available that are designed to hold the axle in place to prevent them comming out when the clip breaks - have a look at one of these sets and may be the early GT diffs can be used safely .......

jeff denton · 04-17-2005

I just noticed something. The early style diff cover has an oil baffle or something on it, the one that came off the later diff I'm building up does not have this. A search turns up no previous discussion, so here goes...
Can anybody venture a guess what this baffle thing does, would there be an advantage to using it?
Maybe it enhances oil control, but then maybe it could cause some drag, too.
That would be a drag, we need to kick some Mustang butts.
At the race meeting today the Ford boys were showing pictures of their new (kind of legal, maybe) plastic front noses. One had the big blue oval in the center and I pointed to it and said "hey look, they circled the problem!"
Yeah. It's WAR now!

jeff denton · 04-17-2005

Got the spring buckets moved from the early housing to the late one, when company popped in and wondered why? Showing him the difference in axles, wheel bearings, housings, he asked "well how do you know the later axle isn't gonna slide out of the bearing?"
Good question. Is that retainer reliable? Should I tack it to the axle shaft with a few welds?
Any opinions??

hrcollinsjr · 04-17-2005

Jeff,

If you've seen one pressed on I don't think you would worry. Get you're other ducks in a row. Don't you dare let the Mustangs and God forbid if any Pintos are in your class and one of them beats you.

The Mustangs can be beat with ingenuity, a well set up car, and a good driver. You have a wealth of knowledge on this list to draw from the rest is up to you. Watch the blue oval boys they like to whine we they get beat and then the rules get changed because they weren't fair. Never mind that they can buy parts off the shelf.

Harold

03-17-2005	#1 (permalink)
apassens Opeler Join Date: Sep 2003 Location: Berlin Posts: 68	Early or late rear end - and how to figure out if its any good I put a replacement rear end into my 71 Gt - Thanks for the donation Bill! - and now 8 month later its leaking at the housing connection between differential and passenger side shaft. But I found a new donor part already. Very rusty...after two hours banging and working it didn't make the brakedrums come off yet... I want to find out is my "new rear end" an early or late model rear end to get the right bearings and restore the whole thing to a decent condition to match the rest of the beloved. The other thing I need to find out is how to identify the integrity of this piece of neglected car history in the first place. The control arm was badly bend - as if someone drag the whole rear end out of the poor car. Somehow I want to ensure to connect this piece safely. How do I visually identify early and late rear ends to order the right bearings for restoration. Is it recommeded to test the donor parts condition to determine use (if so how) or would you recommend to just hold off on a suspect of mistreatment and look for a more promising donor? Or can the one leaking be repaired - if so how?

03-17-2005	#3 (permalink)
tomking tomking Join Date: Aug 2002 Location: SW Missouri Posts: 1,287	I believe you can tell earlier from later models by looking at the backplate which the brake shield bolts up against. The later models are square in appearance while the earlier models have the lower two bolt holes closer together than the upper two bolt holes. Opel gods will confirm or correct. __________________ TMK

03-17-2005	#4 (permalink)
jlthunder 1000 Post Club Join Date: May 2003 Location: Salfordville, PA Posts: 2,143 Real Name: Jeff	If you are leaking oil and the rear is running fine, you can replace the outer seals and bearings for approx 125.00, if you have the new style rear. The parts are available from OGTS and I had a machine shop remove and install the new bearings for 50.00. To remove the axles, while still in the car, put the axle on jackstands, remove the rear brakes, remove the 4 nuts on the backplate. You can then pull on the axle and it might just pop out. If it doesn't you can use a slide hammer and attach it to the lugs and pop it out. I didn't have a slide hammer so I inverted the brake drum, put 2 lug nuts on a few turns and used this as my slide hammer. After 2 bangs with the drum, the axle popped right out. Keep an eye out for any shims in the bearing casing. Are you sure it is gear oil you are seeing and not brake fluid? The rear cylinders do leak when they get old.. __________________ 1972 Opel GT, Owner since 1983 2001 Saab 9-5 SE 3.0 Turbo V6 Weeeeeeeeeee!!! 1973 GT, Parted out, R.I.P. 1968 Kadette, Owner since 2006, Sold, 28 June 2008

03-17-2005	#8 (permalink)
jeff denton former opel racer Join Date: Nov 2002 Location: near some glaciers Posts: 2,863 Real Name: Jeff "Oh-Oh" Denton	The damage to your rear end is kind of strange, I've seen it happen only once and that was in a Chevy half ton pickup which was used as a one-ton (firewood truck...). Hey guys, does this really happen to Opels? Once when I took my S10 to the tire shop for new snow tires I specified it had to be jacked up one side at a time because of the big road chest toolbox bolted into the bed, (once two big guys tried to load it there and couldn't). Sure enough, as I watched from the waiting room a dork slammed a floor jack under the center of the differential and started pumping. I got him stopped and made him do it right. That would have broken the tubes loose from the center housing for sure! That's the only way I can imagine this happening, but even on a little GT? Anyway, before the aforementioned slide hammer trick to get the axles out I definitely would double check something. Pop the cover off and see if there is a little snap ring on the inner end of the axle, between the side gears and the centering pin. Just to make sure you have the later axle and to avoid breaking something if you don't! I've had both styles apart now and that's the only way I'd trust myself... What Bob called a "c-clip" is what I refer to as the "little snap ring", extremely inferior to the way chevy's do it with a "c-clip". This is what scares me about using the early rear end in my race car... __________________ No Opels were harmed in the filming of this movie. However two Mustangs, a Pinto, and a Capri were hospitalized. One Mustang was euthanized the next morning. Last edited by jeff denton; 03-17-2005 at 10:10 PM.

03-18-2005	#10 (permalink)
jeff denton former opel racer Join Date: Nov 2002 Location: near some glaciers Posts: 2,863 Real Name: Jeff "Oh-Oh" Denton	Right. Thanks to Darin (Rallye73) I have a later rear end, disassembled and ready for the 4.22 gears thanks to Stan Czacki! So we're on track, hopefully, in the differential department... __________________ No Opels were harmed in the filming of this movie. However two Mustangs, a Pinto, and a Capri were hospitalized. One Mustang was euthanized the next morning.

03-17-2005	#2 (permalink)
nobody No Access Join Date: Nov 2003 Location: in transit Posts: 3,873	There is a variation in the air breather late to early models.Later models had a plastic cap. There is also a variation in axle bearings, later used a roller bearing and the early used a axle type.

03-17-2005	#6 (permalink)
hrcollinsjr 2200 Post Club Join Date: Jan 2003 Location: Chapel Hill, TN Posts: 2,267 Real Name: Harold Collins	The slide hammer I used was similar to reversing the drum except I used a bigger hammer, the wheel/tire. It takes very little effort. Early model axles used a folder lever on the e brake shoe and a ball on the cable end Late model axles used a hooked lever on the e brake shoe and an eye on the cable end Harold

03-17-2005	#7 (permalink)
apassens Opeler Join Date: Sep 2003 Location: Berlin Posts: 68	Thanks! So I checked it and the replacement axle is a late model. I am sure the leaking one is not leaking brakefluid. Its wet were axleshaft housing and differential housing meet. Not at the end seals or below the brake fluid devider etc. So I better get the old thing fixed up... Guess my weekend plans were just determined. Thanks Y'all. Andreas

03-17-2005	#9 (permalink)
hrcollinsjr 2200 Post Club Join Date: Jan 2003 Location: Chapel Hill, TN Posts: 2,267 Real Name: Harold Collins	Don't use the early rear end in your race car. I've seen an axle come out in the same turn, TWICE! We packed it up and watched the rest of the racing that day. Harold

03-18-2005	#11 (permalink)
Killer Texas GT Senior Contributor Join Date: Jan 2003 Location: Leonard, Texas Posts: 888	As She Screamed Also from experience, it is no fun to be sitting on the side of the road because the 'C' clip broke leaving the axle, wheel and brake drum lying beside your car. Especially when you where going 70 mph on a clover leaf entrance to the highway (yellow speed sign said 25 mph) and the axle is knocking on your passenger door, while your wife slaps the sh_t out of you, the rear of the car drops as if you blew a tire, while pulling off to the side of the road your rear wheel passes you, and as she screams in your deaf ear, "I will never ride with you again in this GT". That was at least 5 years ago and I still have to beg her to go for a ride in the GT. I no longer run the early rear end for that reason, late model or Impulse rearend is the way for now. rk Last edited by Killer Texas GT; 03-18-2005 at 10:01 PM.

03-19-2005	#12 (permalink)
jeff denton former opel racer Join Date: Nov 2002 Location: near some glaciers Posts: 2,863 Real Name: Jeff "Oh-Oh" Denton	Wow. Every time I look at that early style I just wonder what those Germans were thinking! And we gotta quit calling the retainer a "C-clip". It's just a regular old external snap ring. The "C-clip" method is what you see in a Chevy, and I've never seen one fail yet. Of all methods, I like the Ford style, or in Opel terms, "later axle" because you can change a bent axle without pulling the cover, dealing with gear oil and sealant... wanna guess how many times a season I have to help somebody change a bent axle at the racetrack? As if you could bend an Opel axle. Everybody who sees mine is shocked at the diameter of the axle shaft! I don't think a one-ton has a bigger shaft... Has anyone ever bent an axle in a GT? Back to the topic of this thread, I was looking at my bare (later) housing, and it appears the tubes must be hot/cold shrink fitted into the center housing and then plug welded. I wonder how Andreas tube came loose and started leaking? __________________ No Opels were harmed in the filming of this movie. However two Mustangs, a Pinto, and a Capri were hospitalized. One Mustang was euthanized the next morning.

04-17-2005	#15 (permalink)
jeff denton former opel racer Join Date: Nov 2002 Location: near some glaciers Posts: 2,863 Real Name: Jeff "Oh-Oh" Denton	I just noticed something. The early style diff cover has an oil baffle or something on it, the one that came off the later diff I'm building up does not have this. A search turns up no previous discussion, so here goes... Can anybody venture a guess what this baffle thing does, would there be an advantage to using it? Maybe it enhances oil control, but then maybe it could cause some drag, too. That would be a drag, we need to kick some Mustang butts. At the race meeting today the Ford boys were showing pictures of their new (kind of legal, maybe) plastic front noses. One had the big blue oval in the center and I pointed to it and said "hey look, they circled the problem!" Yeah. It's WAR now! __________________ No Opels were harmed in the filming of this movie. However two Mustangs, a Pinto, and a Capri were hospitalized. One Mustang was euthanized the next morning.

04-17-2005	#16 (permalink)
jeff denton former opel racer Join Date: Nov 2002 Location: near some glaciers Posts: 2,863 Real Name: Jeff "Oh-Oh" Denton	Got the spring buckets moved from the early housing to the late one, when company popped in and wondered why? Showing him the difference in axles, wheel bearings, housings, he asked "well how do you know the later axle isn't gonna slide out of the bearing?" Good question. Is that retainer reliable? Should I tack it to the axle shaft with a few welds? Any opinions?? __________________ No Opels were harmed in the filming of this movie. However two Mustangs, a Pinto, and a Capri were hospitalized. One Mustang was euthanized the next morning.

04-17-2005	#17 (permalink)
hrcollinsjr 2200 Post Club Join Date: Jan 2003 Location: Chapel Hill, TN Posts: 2,267 Real Name: Harold Collins	Jeff, If you've seen one pressed on I don't think you would worry. Get you're other ducks in a row. Don't you dare let the Mustangs and God forbid if any Pintos are in your class and one of them beats you. The Mustangs can be beat with ingenuity, a well set up car, and a good driver. You have a wealth of knowledge on this list to draw from the rest is up to you. Watch the blue oval boys they like to whine we they get beat and then the rules get changed because they weren't fair. Never mind that they can buy parts off the shelf. Harold

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