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Replacing rear end pinion seal on 1950 Dodge Meadowbrook


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In a few months, I will be at a point where I'll have to replace a leaking pinion seal on the rear differential of my 1950 Dodge. Examining it, here's the steps I see...

1) Drain oil

2) Remove bolts connecting rear yoke (or flange?) to drive shaft and move shaft out of the way

3) Remove cotter key from castle nut (or flange nut) and remove castle nut from the pinion shaft

4) Remove yoke

5) Remove the case bolts and work the case cover free and replace seal and gasket...

However, I have learned that the castle nut (step 3) also serves to pre-load the pinion bearings.

I don't have the tools to properly torque the castle bolt back into place when I reassemble everything.

Am I crazy to think that I can keep track of the exact position of the castle nut before I remove it, then be very careful to tighten it back into exactly the same position???? Can I hope that the pre-load will be preserved by following such steps? Anyone done this already?

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It is possible to do that if you are careful. It has been done that way many times, if you do not change the preload everything will be ok.

If there is no gear whine and no excess play in the gears, that is the best way to do it.

Retorquing only works if you replace the crush spacer and there are other details to getting it right.

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I may be reading this wrong but if you only need to replace the pinion seal you don't need to drain the oil or mess with the carrier gasket. Remove the drive shaft at the differential, remove the pinion nut, remove the yoke, remove the seal, install a new seal and everything else again. I believe those old Chrysler differentials use a spacer and shims to preload the pinion bearings, Not a crush sleeve. If this is correct, it would be hard to overtighten the pinion nut.

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OK.. maybe I'm asking the wrong question!! I would have thought that the pinion seal is inserted from the inside of the case and is held in by a lip on the case. Can it be installed from the outside?

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OK.. maybe I'm asking the wrong question!! I would have thought that the pinion seal is inserted from the inside of the case and is held in by a lip on the case. Can it be installed from the outside?

Just double checked the '46 to '54 Plymouth factory service manual (pretty darned sure Dodge is the same as Plymouth in this regard) to verify that the basic design concept is the same as for my much older car. You should pick up a service manual for your car!

The seal can be removed and re-installed "from the outside". Bearing preload is set by shims. The pinion flange nut is torqued to 175 ft-lbs when you put it back together.

Not in the manual but you should check the surface on the flange that the seal works against. If it is damaged at all, get a speedi-sleeve installed to give you a smooth surface for the seal to seal against.

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If you cannot pry the seal out try drilling a small hole in it, then put a screw in that hole and pull it like a nail.

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Hey frcc16, This job can be accomplished in just a few minutes if you have a lift ro raise your car on. Even outside under a shade tree it is not a very hard job. Getting the old seal out is sometimes hard. Just drill a hole in it and run a self tapping screw in and either pry the seal out or using visegrips on the screw and a hammer on the visegrips. Seals with a lip can be removed with a screwdriver and a hammer.

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The factory seal can be tough to pull out with out the right tools.

The screw trick will work-maybe. You might end up totally destroying the OE MoPar seal to get it out. Do what ya gotta do to remove it. Just don't nick the case or pinion flange. You will need to hold the pinion flange firmly to be able to remove the cotter pin and 1-1/4" nut.

An 1/2" impact gun will quickly remove this nut but....... could damage a gear- I say could!

Aftermarket replacement seals are very wimpy in construction compared to the OE seal and can be easily removed as they have hardly any thick steel in them.

A scew type factory seal removal tool used to remove the same type seal on the rear of a 1950 Chrysler M6 Trans shown....

Bob

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As having replaced many diff pinion seals in my time as an Auto mechanic, I would offer the following as a suggestion to prevent any issues with pinion bearing preload on re-assembly.

Mark the position of the nut, the pinion shaft and yoke before you undo it all and start removing things. A gentle centre punch mark across all 3 elements on a straight line will do the job well. Take a picture of it all with the witness marks before you dis-assemble it all....

Use a long holding tool on the pinion flange ( a pipe wrench works well as it has a long handle that you can wedge against the floor ) to hold the pinion static and not load the diff gears when undoing the pinion nut...... the nuts can be extremely tight on older vehicles and bigger diffs.....

Sometimes you may not be able to get an impact socket on to the nut so have to use a normal thin wall CRV socket to suit and a large breaker bar....

If you jack the front of the vehicle up, then all the oil should stay in the final drive diff housing when you pop the seal out.

Generally a pry bar will pop the seal out of the housing, but be carefull to not damage the counter bore in the housing otherwise it may leak oil from the O.D of the seal if you create a leak path.....Also the seals can fly out and cause damage to the seal removal tool operator so pls be carefull you don't wear it , as I did one time......

When you re-assemble - lube the seal lips and check the pinion for seal tracking, if there is a groove worn then a Speedi Sleeve is a good repair option.....

Install the seal using a suitable installing tool like a large 3/4 drive socket or seal drivers....

Align all the punch marks back up and then re-assemble it all in exactly the same orientation as it came out....

Re-tighten the pinion nut to align the witness marks and you should be good to go.

Best of luck :)

Oh - Don't forget to check , refill the oil level if the seal has been leaking ...

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Thanks for the help with this..... I just spotted a disturbing thread on this posted back in 2005. The jest of it was that you really need a hefty impact wrench to loosen the flange nut. OK, well I don't even have an air compressor! It was encouraging to hear that these nuts can be loosened with a breaker bar!

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Yes , most definitely can break out the nut with a breaker bar, the trick is getting enough purchase on the bar ( especially if you are working above ground level) I used a 24inch bar on most occassions, and holding the pinion still to break out the nut..

Its quite simple if you have a hoist as you can gain some mechanical advantage on the breaker bar....

Most pinion nuts on cars are tightened anywhere from 100 to 150 ft.lbs initially to get the crush / bearing preload correct on the pinion.

Cheers

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  • 1 year later...

Well,  up to yesterday, I had resigned to leaving removing the castle nut to a mechanic with the right tools.... BUT, yesterday, I decided to at least have a look at it an see if I had a shot at loosening it myself....  I removed the drive shaft, pulled out the cotter pin and......

 

WAS ABLE TO REMOVE THE CASTLE NUT WITH MY FRICKEN FINGERS!!!!  It wasn't even tight!!!!  Yikes!

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In hopes that when torqueing it back up it still rotates freely.

Probably will but I always prepare for the worst and hope for the best.

 

I have a 52 Plymouth parts car here if you end up needing a rear end.

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  • 5 years later...

Morning so I as well am having some issues I had to drop rearend to remove drum and hub off of my 53 dodge meadowbrook (Dont Ask LOL) long story I as well did not do my research as to marking the nut so I am stuck there as well but I cannot take the differential so my question is is there any like key or snap ring holding it together picture circled in red  to remove the axle I will need to do the axle bearings as well any help would be greatly appreciated thank you 

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Hwellens thank you for responding but the trouble I am having is it seems to be locked somehow cant pull that piece that is circled in red or the neither from the axle side just wondering if there is and clip snap ring bolt holding it together maybe 

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You have circled the whole third member.

Both axles have to be pulled far enough to let the third member out.

I see that you have the drums off so it is just a matter of pulling the axles hard enough to get them out.

You could use a drum as a sliding hammer of sorts, by putting it back on loose and start the nut and yanking it against the nut like a hammer. The axle should come out that way. (hoaky maybe but it works) Once you take the backing plates off as you show in one of your photos there is nothing else holding them.

The inner ends of the axles almost touch each other in the center of that third member.

It is quite possible that that center section will the glued so to speak after all these years as well. 

By the way, when it comes loose the oil comes out.

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I had found an old slide hammer puller with the adapter for threaded axles at a rental place that has been in business forever when I needed it. If you know any places like that you may want to check with them.

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Ok update Gentlemen so I cleaned up my rear end to locate those numbers and this is what i found it looks like 2.84 in first picture if I'm not mistaken and this long number looks yo be 1141544-49 and I think it looks like OD and cant really make out the letters under the OD  in second picture is right under it please if anyone can help me make it out as to what ratio and etc. I need to know please 

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I do not think that has anything to do with the ratio. When you pull out the rear end the ratio is sometimes stamped on the ring gear. If not count the teeth on the ring gear and divide that by the teeth on the pinion and you will have the ratio. My guess is it is a 4.11.

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That 1141xxxx number is the part number of the differential carrier housing only. Checking my part books it’s about right sequence for 1953.  MoPar changed the number in 1954 to a 13xxxxx series so I can’t verify 100% as I have the updated 1954 issued book. A 1950 dodge was 1411543 so your number makes sense. It looks like the sixes had around a 3.9 ratio and the V8 was 3.7 something.

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27 minutes ago, hwellens said:

I do not think a V8 was offered in a 50 Dodge.

You are correct however this poster has a 1953 Dodge, he just tagged on to an old post about a 1950 Dodge.

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To remove the center section you must first remove the axles, This is done by removing the 5 ? bolts that hold the backing plate on, there is a bearing retainer - possibly with shims under the backing plate.  a few bumps with a slide hammer or weight on a chain should pull it out.  If you are planning to take the diff gears out mark the position of the adjuster rings with a center punch before removing the caps. But if you are in to it that far you NEED a manual. 

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Here's what I do sometimes a ratio, or at least get close.

Jack the rear end up (both wheels off the ground.

Make a chalk mark on both wheels and one on the drive shaft. IN THE SAME PLACE, like at the bottom.

IMPORTANT ! Turn BOTH wheels together using the chalk marks to make sure you are turning them together.

As you do this count the number of times the drive shaft turns in one wheel rotation.

The ratio will be how many times the drive shaft turns.

Like a little over four turns might be 4:11-1, or 3 1/2 turns will be 3:50-1 and so forth.

I know, farm tricks but works for me.

 

I don't ever remember seeing a ratio in the casting numbers, I have seen tags under a cover bolt before that has the ratio stamped on it.

Edited by JACK M (see edit history)
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Ok another update and help again so I bought this rear end off it's off of a ranger for my meadowbrook so it looks like my rear end is a little longer by a few inches so was told  that I could just add  spacers to bring out the wheels where the need to be but would like to know about the perches and other mounts go a few pics to show where I'm at and any help again would be great thank you I also already ordered my flange yoke for my driveline as the ranger plate is a pattern for the 1210 series and the '53 is the 1310 series so needed ons made to fit the differential plate 

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Edited by Crisjr14
Forgot pis (see edit history)
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Ok so can someone please tell me what this means and will it affect my swap of the rear ends so the tag on the ranger rear end has this tag and from what I see in this chart it says that the rear end is a limited slip axle so what does it mean and will it still work on my '53 please

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Limited slip means both wheels are driven, in some circles also known as posi-traction.  Good for mud, sand and snow use.  My experience with Dodge and Plymouth is original stuff only which generated the good luck comment above.  You will need a person who has made a swap like this to take you under his wing.

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