Joe12459
Well-Known Member
Measurement "A" is 52.5" for 904 trans with 8.25 rear end. I know this for sure, as I just installed one in my son's car.
7.25 to 8.25 in a J
- Thread starter Bruceynz
- Start date
I’ve been traveling and not been able to type.
Shaft measurements are Center Eye to Center Eye of U-Joint.
That distance is not easy to figure out (easily).
If propeller shaft has same U-Joints on both end (and should have, unless a custom shaft), the trick is to measure from U-Joint cap to U-Joint cap.
Cap one is easy to hook a tape measurer on.
Cap two gives a clear concise line at the beginning of the cap.
This shaft is from an ‘84 Gran Fury Police (M-body) 904 and 8-1/4" differential.
It helps to have two people with this, for tape measure end has a tendency to wonder, but not required. Hold one end of tape to cap end.
Measure from the Red line, and not the Blue Line
I had to rob the slip yoke from this shaft - so is missing on my shaft. Line up tape to same end of second U-Joint.
In this case, this shaft measures 52-3/4" (which DOES NOT apply to your J-body).
Shaft measurements are Center Eye to Center Eye of U-Joint.
That distance is not easy to figure out (easily).
If propeller shaft has same U-Joints on both end (and should have, unless a custom shaft), the trick is to measure from U-Joint cap to U-Joint cap.
Cap one is easy to hook a tape measurer on.
Cap two gives a clear concise line at the beginning of the cap.
This shaft is from an ‘84 Gran Fury Police (M-body) 904 and 8-1/4" differential.
It helps to have two people with this, for tape measure end has a tendency to wonder, but not required. Hold one end of tape to cap end.
Measure from the Red line, and not the Blue Line
I had to rob the slip yoke from this shaft - so is missing on my shaft. Line up tape to same end of second U-Joint.
In this case, this shaft measures 52-3/4" (which DOES NOT apply to your J-body).
Bruceynz
Well-Known Member
Thanks Bud,
Hey I see on your tape measure we share the same last name
See You
Bruce
Hey I see on your tape measure we share the same last name
See You
Bruce
Bruceynz
Well-Known Member
Drive shaft is out, here are some pics, so 52.5" is what I get it cut to, no going back once its cut
7T8 Custom
Well-Known Member
Well you can still make shorter but stretching it is a little tough.
Bruceynz
Well-Known Member
Drive shaft will be ready on Wednesday Making progress slowly
When I drop the 7.25" rear end do you just undo the park brake cables inside the brake and then use them on the 8.25" (the 8.25" still has them connected)
Making progress slowlyWhen I drop the 7.25" rear end do you just undo the park brake cables inside the brake and then use them on the 8.25" (the 8.25" still has them connected)
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If you have 10" brakes, the parking brake cables (from backing plate to frame rail) should be the same (a small chance I might be wrong - only because I don’t know what year your 8-1/4" came from). I do know 11" brake cables are different.
It is far easier to disconnect the cables from the frame rail, than from inside the brake drum.
Just measure the cables first. If the same length, then just use the cables that came with new differential.
That said, It might be a great idea to install new rear wheel cylinders, brake shoes and the rubber brake hose (not mandatory, but a good idea).
It is far easier to disconnect the cables from the frame rail, than from inside the brake drum.
Just measure the cables first. If the same length, then just use the cables that came with new differential.
That said, It might be a great idea to install new rear wheel cylinders, brake shoes and the rubber brake hose (not mandatory, but a good idea).
Bruceynz
Well-Known Member
Fitted new wheel cylinders, brake shoes and springs were good shape so left them on. Brakes are 10", rear end came out of a 1976 Aspen R/T from memory.
This is what the brakes looked liked before I replaced the slaves, I cleaned them up and all looked good.
This is what the brakes looked liked before I replaced the slaves, I cleaned them up and all looked good.
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Looking good!
I forgot to mention, removing a brake cable from backing plate is a royal PITB - and not something one will want to do a lot of.
I forgot to mention, removing a brake cable from backing plate is a royal PITB - and not something one will want to do a lot of.
Bruceynz
Well-Known Member
working on old cars is a right pain in the butt, everything is rotted on hard or tests my patience's right to the last turn! But what I get out of it at the end is something other people say oh I wish I had a car like that, or that's a cool ride and I know I have wrenched on every dam bolt in the thing to make it how I wanted it. Its far more easier to buy a modern car and not have an argument with the wife for spending to much time in the garage but hey what can I say I have the mopar bug!
Got me old Dad to thank for that, in NZ we had lots of English and Aussie cars, USA cars were few and far between and cost a lot, my father had a 1967 Belvedere 383 and a 1967 New Yorker. Both in their day cost as much as a house!!!!
Got me old Dad to thank for that, in NZ we had lots of English and Aussie cars, USA cars were few and far between and cost a lot, my father had a 1967 Belvedere 383 and a 1967 New Yorker. Both in their day cost as much as a house!!!!
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80mirada
Well-Known Member
Acetone mixed 50/50 with ATF makes a great penetrating fluid, and it is cheap, put it in a cheap spray bottle. Tell the wife that at least you aren't chasing other women.
Bruceynz
Well-Known Member
2 more U bolts to undo and the 7.25" will be free, dunno why but you bolts always seem to need replacing the threads are always hard as concrete and fight you to the end, getting 4 new U bolts made up today, should be ready to pick up tonight, driveshaft will be ready either tonight or tomorrow so slowly making progress. Oh by the way those funny spring out clips around the park brake cables with the fingers that are hard to undo found out you slide a 13mm ring spanner over them and they pop right out!
A hose clamp can work, as well - but still a major PITB.
I wouldn’t reuse U-bolts more than a five years old (ten years tops), so yea, on these cars, always replace the U-bolts and nuts.
For some reason, Chrysler always called U-Bolts “clips”. I have no idea from where or how.
I wouldn’t reuse U-bolts more than a five years old (ten years tops), so yea, on these cars, always replace the U-bolts and nuts.
For some reason, Chrysler always called U-Bolts “clips”. I have no idea from where or how.
Bruceynz
Well-Known Member
Dunno why but they are like they are cross threaded and hard has hell to get undone! Was the same on my 1980 Chrysler New Yorker when I had the springs off that.
Bruceynz
Well-Known Member
Hard to do by yourself but I got the 7.25" out and the 8.25" is bolted in. Can't believe the weight difference between them. Will start work connecting everything up tomorrow night after kids go to bed.
Looking nice!
I generally install the differential in a different manor (I’m lazy).
In a garage like this, I would either:
Leave the leaf springs attached to differential (and wheels) and roll it all out from under car.
OR
Unbolt both rear half of leaf springs and roll differential out from behind car (with wheels still attached and springs dangling on car).
Carrying the differential over the leaf spring is too much work for me.
Removing the rear end.
I might recommend removing the Iso-clamps at this time – or at least consider it before bolting everything back together.
BudW
I generally install the differential in a different manor (I’m lazy).
In a garage like this, I would either:
Leave the leaf springs attached to differential (and wheels) and roll it all out from under car.
OR
Unbolt both rear half of leaf springs and roll differential out from behind car (with wheels still attached and springs dangling on car).
Carrying the differential over the leaf spring is too much work for me.
Removing the rear end.
I might recommend removing the Iso-clamps at this time – or at least consider it before bolting everything back together.
BudW
Bruceynz
Well-Known Member
Hi Bud,
Wanted to remove ISO clamps but don't have time so have put nolathane spring pads in. Has stiffened up the rear ends sideways movement heaps!!
Wanted to remove ISO clamps but don't have time so have put nolathane spring pads in. Has stiffened up the rear ends sideways movement heaps!!
Thunbs up!
Bruceynz
Well-Known Member
Those nolathane spring pads make a HUGE difference, you can't push the rear in and out, with the old rubber ones you could push it and it was like the rear was on jelly, if I am not happy I can always change to home made steel pads. When you do the iso clamp up should it do up tight against each other? If you look at my photo you can see a gap between the top plate and the U shape clamp part.
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I can’t see the gap – but don’t have any reason not to believe you. The upper and lower plates should be touching. It might be OK as is - but I don’t think I will want to drive a car that way.
I’ve seen a few of the lower plates tear out at the U-bolt holes.
I can’t point a finger if it was because bolts were loose, rust, or from what (the ones I seen, rust had nothing to do with plate failure).
All of them were not from high performance usage.
If I was in your situation, I would take a file (or grinder) and file down the red biscuits down a smidge so the two metal plates touch.
Actually, what I would do is keep the upper plate there, remove the two red biscuits, and either buy or make a lower plate that looks like the picture that I swiped from Firm Feel (below). Note: this might require longer U-bolts.
Removing the top biscuit will raise the rear a bit (½” maybe ?)
BudW
I’ve seen a few of the lower plates tear out at the U-bolt holes.
I can’t point a finger if it was because bolts were loose, rust, or from what (the ones I seen, rust had nothing to do with plate failure).
All of them were not from high performance usage.
If I was in your situation, I would take a file (or grinder) and file down the red biscuits down a smidge so the two metal plates touch.
Actually, what I would do is keep the upper plate there, remove the two red biscuits, and either buy or make a lower plate that looks like the picture that I swiped from Firm Feel (below). Note: this might require longer U-bolts.
Removing the top biscuit will raise the rear a bit (½” maybe ?)
BudW
