rear axle bearing

[Jerry T]

I am trying to replace the oil seal behind the rear bearing on a 51 desoto custom...I see a small bolt for oil inspection I assume as that is what it is on the blowup of the rearr end..Also Iam confused as to whether the rear bearing is greased like the front bearings or oiled from the 90 weight oil  like most others?   there is a seal on the backing plate and the manual calls the other behind the bearing an oil wassher?   

[Plymouthy Adams]

you state you have the manual, may I suggest you go to t he lubrication section as this spells out what when and where of the many lube points, lube oils used and where to apply...it is all good reading for sure....

[Dartgame]

The small bolt is actually a grease inlet for the bearing. The bearing is greased and is not lubricated by gear oil. Pretty standard R&R procedure, pull brake drum off tapered axle shaft, remove woodruff key, remove backing plate, pull axle with bearing cup, note shims (put them back in when reassembling assuming you dont change bearing), yank out inner seal. Reverse procedure for installation.

[desoto1939]

this is rich Hartung with a 39 Desoto.  Yes the little nut that you see on the axle housing just before the backing plate gets removed.  AGAIN DO NOT use a lube gun under pressure to insert grease into the bearing.  It will put too much grease into the bearing and then push the grease out of the axle shaft and onto the brake shoes.  When reading the service manual you put some bearing grease on your  thumb and then push that into the smallhole to  get grease into the bearing it does not take a lot of force just pack the bearing.

 

You do not have to pullthe axle out to lube this bearing from the back just follow the above steps.  I have owned my 39 Desoto for 32 years and this is the recommended steps.  ALso replace the nut after putting the grease in. Do not put a zerk fitting into the hole because someone who does not know your car will use a high pressure lube gun and put too much grease into the bearing and then mess up your brake shoes.

 

Rich Hartung

desoto1939@aol.com

[Dodgeb4ya]

That rear inner seal....seal replacement might look different....you should replace the thin outer one too. Clean and re-grease the axle bearing rollers/race and a little in the bearing housing cavity. re-assemble as mentioned.

Don't mix different base types of grease.

Edited December 3, 2019 by Dodgeb4ya

[James_Douglas]

While one is at it...

 

There is a tech note someplace in the MOPAR service booklets. about 1955 ...

 

That the axle shaft end play should be increased due to the "new freeway speeds" that is causing heat and the axles are "growing" and causing the axles to bind on the center block in the gear set.  I think most are listed as having .003 to ,008 inch of play. The tech note I read someplace suggested going up to about .015 or so. I cannot remember is it was in the little service books, a later MOPAR year specific manual or a "Motors" multi-year big blue book.  I did go with .012 or .014 as I remember on the 1949 when I did it.

 

James.