installing rear drums

[Los_Control]

Seems fairly straightforward, just asking for a friend 

 

First time I ever have installed drums on a tapered axle. Have a question about proper procedure.

Looked in my Motors repair manual under axle and brake section, I see nothing helpful. So excuse me if I missed it.

 

When we install front drums, would snug them down good, to seat the bearings, then back off for proper bearing clearances.

 

On a tapered axle, I am concerned with torque required to pull the drum onto the taper and into proper position.

I see no torque specs ... so I used impact gun and and snugged it up fair, without hammering on it?  Needing to adjust the nut to install cotter key, should I go tighter or looser?

 

Do we just hammer it on with the impact and get on with our day?

Or is there a proper procedure to follow?

[P15-D24]

Slide them on, align and replace the key, then torque.

Might put a very thin coat of grease on the taper to make removal easier next time. 

[Young Ed]

There is a torque spec I believe 168 lb ft and then you go tighter until the cotter pin lines up. That being said I have typically just rattled them on hard and then put the pin in. 

[Los_Control]

10 minutes ago, P15-D24 said:

Slide them on, align and replace the key, then torque.

Might put a very thin coat of grease on the taper to make removal easier next time. 

Thank you ... I cleaned up with a wire wheel and put oil on them, I expect to remove after getting hydraulics working for proper adjustment.

 

3 minutes ago, Young Ed said:

There is a torque spec I believe 168 lb ft and then you go tighter until the cotter pin lines up. That being said I have typically just rattled them on hard and then put the pin in. 

Thats exactly what was wondering ... I was very light on the trigger ... as if installing the tire/wheel 95-100 pounds.

 

I am thinking more is better, then wondering if will create other issues with free play ... Thanks for reply.

[Young Ed]

44 minutes ago, Los_Control said:

Thank you ... I cleaned up with a wire wheel and put oil on them, I expect to remove after getting hydraulics working for proper adjustment.

 

Thats exactly what was wondering ... I was very light on the trigger ... as if installing the tire/wheel 95-100 pounds.

 

I am thinking more is better, then wondering if will create other issues with free play ... Thanks for reply.

If they aren't tight enough the drum will shift on the key when going forward and backwards. When I first built my 46 pickup I had an odd noise like a little ping when starting out. I quickly figured out it was only starting out after having gone backwards. The drum shifting because the nut wasn't right enough was causing it. Luckily the only damage was one key. 

[JBNeal]

FWIW I put a verrry thin coat of grease on my tapers and hub bores, and when I pulled the drums off 10 yrs later for the 10k checkup,  all I needed to do was rap the hub then the edge of the drum with a rubber mallet and them drums popped right off...not a lick of rust had formed on the taper or hub bore, and that's something for a truck that's been basically parked outside, so that grease did a fine job of displacing moisture

[Merle Coggins]

I've always been taught that a taper shaft like these need to have clean metal to metal contact. The tight metal to metal contact helps to transfer the torque to take the stress off the key. 

I would rather need to use my puller again later than risk having a hub slip and shear a key because I used lube.  

[Los_Control]

Story time ... @Young Ed

I appreciate and thank you for your experience. You actually just did it and learned from past how to do it right.

I guess I should not ask and also learn on my own. I have good intentions, what I learn I can pass on to others.

 

My past employer used to get so mad at me asking questions.

I was a apprentice learning finish carpentry, I would ask many questions  ... after 2 years I was asking a question while I was grinding away on a curved oak stair rail.

Boss blew up .... "took me 30 years to learn this trade" you are learning in 2 years ....

 

I shrug my shoulders, you paying me by the hour boss, you want me to learn on your dime, or show me the correct way? He showed me.

 

I do not deserve to be given this information, yet I want to take personal advantage of it ... and pass it on to others.

[JBNeal]

1 hour ago, Merle Coggins said:

I've always been taught that a taper shaft like these need to have clean metal to metal contact. The tight metal to metal contact helps to transfer the torque to take the stress off the key...

I regret not having taken pictures of the shafts and bores after disassembling to show some of the details I saw during my field testing analysis...when I say verry thin layer of grease was applied, I basically smeared on with one finger, then wiped off with a clean finger...this left a grease layer so thin that it almost did not look like there was any grease on the shafts or bores,  but it was there.  When I disassembled 10 yrs later, I took a white paper napkin and wiped down the shiny shafts and bores to see the original green grease residue on the paper...the surfaces felt slightly tacky, and the key and keyways were pristine, with faint line witness marks on the keys.  There were some indications that the bores and tapers were slightly non-concentric from imperfections in the machining process...these shiny areas had practically no grease residue, so I assume that there was some interference in these areas and the grease was displaced.  These interference areas would have effectively given the dry fit that is desired to protect the key from shear.  This subtle lubrication trick was shown to me by a mechanic who worked on old stuff, and he mentioned that he learned it from older mechanics as well when he was dodging german bullets back in the 40s, back when they needed to keep their equipment not only running but be able to service it in the field and in a hurry, during nasty weather or while staying a few steps ahead of belligerent bohemians...so they learned all kinds of little tricks to reduce service requirements that transferred to civilian life

[MBF]

I used a light coating of Never-seize on the rear of my 36 and 40 Plymouth’s years ago when doing rear cyls and they came apart easily about a year ago when sleeving  the cyls on the 36.  A whole lot easier than the first time!

[Tooljunkie]

And i thought it was taboo to grease shafts. Good to know. 
Was trying to pull a drum off my spare diff for a buddy, its staying there. I have the proper drum puller (snap on) and i pretty much destroyed it. The nut was “hold the whole truck together “ tight.