Rear end axle replacement tip 1948 Plymouth

[Thomba48]

Hi,

I am in the need to replace the rear axle of my 1948 Plymouth business coupe. Being in Germany US stuff isn't that easy to come across. And getting it over from the US a rather dear experience.

I am offered a rear end 8 3/4 axle complete with high performance breaks from a 1968 or 1970 Plymouth road runner. Would anybody know if that would possibly work?

Thanks

[claybill]

i would suggest you stay with the original parts..to avoid the future problems

that are sure to develop. p15 stuff is easily come by...

bill

[Merle Coggins]

If the width is the same then it should work fine. I think someone here has a chart with axle widths from various Mopars. Maybe that'll help out.

[BobT-47P15]

I think Don Coatney may have posted that chart in the reference section

of the forum. There is a pretty extensive list of things that should

work....with minimal problems.

[Plymouthy Adams]

Body line Track Perches Notes

A-body, 65-72 55.6 43.0 4" lug bolt circle

B-body, 62-70 59.2 44.0

B-body, 71-72 62.0 47.3

B-body station wagon, 71-72 63.4 47.3

C-body, 64-72 63.4 47.3

D-body, 64-72 63.4 47.3

E-body, 70-74 60.7 46.0

The roadrunner is B body

[greg g]

You will need to modify and move the spring perches and likely have a new driveshaft made or at least modified to accept the newer style rear universal joint, but it is doable. Do you have any idea what the gear ratio is??? If Jeep Cherokees are available thee they are a good source also, and the gear ratio is usually 3.55 to 1.

[Plymouthy Adams]

if he is lucky that roadrunner will have a 3.23 maybe even a posi..

[Thomba48]

Thanks as usual - this forum is so helpful.

Now - in addition to the original question - I would like to rephrase my question: What "newer" type of rear axle should I be aiming for in order not to be required to undergo dramatic adaptations. Again - 1948 original stuff is not easy to come by here in Germany. By type I mean model etc.

Sorry - I wasn't able to find Don Coatneys specification chart. Any further clues to where to find this input resource?

Thanks

[BobT-47P15]

Part of that chart is contained in Tim Adams' post above.

Here's a complete one as far as I know.

Challenger (E-body) rear is 60.70"

Mopar Outside

Width Year Model

55.60 1960-1976 7 1/4 A-body

55.60 1973-1976 8 1/4 A-body

55.60 1966-1972 8 3/4 A-body

55.60 All 8 3/4 A-body

56.00 1932-1934 All Mopars

57.40 1963-1972 7 1/4 A-body

58.54 All 8 1/4 F-body

58.54 All 8 1/4 M-body

58.54 All 8 1/4 J-body

59.00 1935-1936 All Mopars

59.14 1966-1970 9 3/4 B-body

59.20 1962-1970 8 3/4 B-body

60.00 1937-1948 All Mopars

60.70 All 8 3/4 E-body

60.70 All 9 3/4 E-body

62.00 All 8 1/4 B-body

62.00 1971-1974 8 3/4 B-body

62.00 All 9 1/4 B-body

63.40 All 8 1/4 C-body

63.40 1971-1974 8 3/4 B-body S.W.

63.40 All 9 1/4 C-body

__________________

[Plymouthy Adams]

Bob...I could not quickly find my early model widths..thanks for filling in the gap..

[makkelsay]

84-89 crown vic

it fits perfect!

3.08 gears and limited slip

[scottyv47]

your best bet is either get another stock one, and do no mods, just bolt it in, because you will at least have to change the spring perches on any other rear you use, and if your going to do that, you might as well do it right, meaning, disc brakes, and the easest most simple way is to get a 1996 or newer ford explorer 8.8 rear, they are the exact width of your rear, 59.75 inches, they have a good gearing, 355, they are as stong as a ford 9 inch, and they have disc brakes, they have a new style yoke, but spicer makes a conversion kit, so you can use your original driveshaft, scottyv

[Thomba48]

Still evaluating all the incoming supports (what would I do without all the help of you guys) am I right in assuming that you all see the original option of the 8 3/4 rear end axle complete with high performance breaks from a 1968 or 1970 Plymouth road runner as no viable option!?

Thanks again

[scottyv47]

its a great option, you will still have to replace the spring perches, the 48's are not in the same location, and there alot narrower, and the rear is half an inch narrower, which isn't a big deal as long as you position the spring perches right, i would still go with the 8.8/disc breaks, if theres any around, scottyv

[RobertKB]

Hi,

I am in the need to replace the rear axle of my 1948 Plymouth business coupe. Being in Germany US stuff isn't that easy to come across. And getting it over from the US a rather dear experience.

I am offered a rear end 8 3/4 axle complete with high performance breaks from a 1968 or 1970 Plymouth road runner. Would anybody know if that would possibly work?

Thanks

If it is only a rear axle you need to replace, I have several. Not sure what shipping would be from Canada, but I could find out. Personal Message or email me if you are interested.

[Andydodge]

Thomba, you have the same problem I have........you ain't in the States, so it is tough when you need to find something like a rear end, at least here in Australia there are a few alternatives, if someone offers you a complete rear end from a 1988-1997 Aussie Ford Falcon Wagon, take it, as they bolt straight in to the 1940-48 Plymouth, but this is probably not gunna happen in Germany........so apart from importing another rear end as suggested by other posts have you checked other European cars, ie, Volvos use a live axle diff, tho' they are GM stud pattern, what about 60/70's Ford Granada rear ends?....I'd check around, btw why do you need to replace the whole rear end anyway?.........it might be easier to repair whats there.......assuming that whats there is there.........lol..........regards, andyd

[dndrodshop]

The E-body 8-3/4 is almost a bolt in.

Those dims are very close to the P-15.

I have two cars with e-body rears.

[knuckleharley]

Guys,I didn't see a measurement for the 8-3/4 rears from 62-64 Darts with V-8's. I have one out in the shop that I plan on using in my 33 coupe,and IF I can remember,I will measure it tomorrow and post the measurements here.

[fredsv8shop]

go ahead with the swap, its a easy bolt in after relocating the spring perches about 2 inches, I did the swap with a 1972 sattelite rear axle in my 1950 business coupe in 1 saturday afternoon, the only special part you need is a adaptor for the drive shaft. But you are lucky I have a adaptor in my garage and I live in the Netherlands, give me a email and we work it out. fredsv8shop@kpnmail.nl

regards

Fred

[Don Coatney]

Here is the chart. I would suggest you look for a ratio of 3.55/1. Anything

higher and your flathead 6 may not pull it well. You will have to modify or

replace the driveshaft when doing this swap. I used an 8 1/4" Dodge Charger

differential and I did not have to re-locate the spring perches. I did have to

weld a couple of 1/4" steel plates on top of the perches to reduce the size of

the spring guide pin centering hole.

[Oldguy48]

I'm installing a rear from a 68 Roadrunner in my P15. Not completed yet, but the length is very close, and just need to relocate the spring perches, and fabricate new spring/shock mount plates, because the axle tube diameter is larger on the new rear. Not done yet, but so far everything looks good.

[Don Coatney]

I'm installing a rear from a 68 Roadrunner in my P15. Not completed yet, but the length is very close, and just need to relocate the spring perches, and fabricate new spring/shock mount plates, because the axle tube diameter is larger on the new rear. Not done yet, but so far everything looks good.

I modified my U-bolts and used the original shock mounting bracket.

[Fireball]

Thomba, also in Germany, as well as here in Finland you will have plenty of Jeep Cherokees and Ford Explorers in pieces at junkyards. Either of those rears fit perfectly, I did put one out of Jeep in my car.

[knuckleharley]

Here is the chart. I would suggest you look for a ratio of 3.55/1. Anything

higher and your flathead 6 may not pull it well. You will have to modify or

replace the driveshaft when doing this swap. I used an 8 1/4" Dodge Charger

differential and I did not have to re-locate the spring perches. I did have to

weld a couple of 1/4" steel plates on top of the perches to reduce the size of

the spring guide pin centering hole.<<

Don,guys,the 62,63,and maybe the 64 A body Dart with the 318 came with a push-button 727 and 8-3/4 inch rear. This is the combo I'm putting behind the DeSoto hemi in my 33 Plymouth coupe.

I just went out to the shop and measured that rear and here are the measurements.

44 inches center to center between the spring pads

50 inches from backing plate to backing plate

58 inches from the drum face mounting surface to drum face mounting surface. There may be a half-inch variation in this measurement because I didn't have anybody to hold the other end of the tape. From the rear of the backing plate to the rim mounting surface of the drum is 4 inches.

I don't know if this rear was ever used in any other Mopar or not. I know the only only 727's that had push buttons and didn't have the emergency brake on the rear where the 62-64 units.

BTW,if any others out there plan on mating a DeSoto hemi to a 727,only the small block V-8 727's will work.

[greg g]

As mationed grab on from a Jeep Cherokee,or Ford Exporer or Ranger Pickup truck and get in contact with Fred. Betch he can have you standing proud with new parts in short order. The other thing to look at if available are Mazda B series Pickup Trucks as they are basically mechanicaly the same as the Explorer. Also Dodge Dakota Pickups if they are present in Europe or Mitsubishi Pickup trucks or light delivey vans. Maybe Ford Transit or similar Mazda.