70sWagoneers

How to remove totque tube?

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1937 Buick Special 40

 

How do i seperate the torque tube from the diff carrier? I believe i need to change my pinion bearings. Also, what is the chance that the drive shaft itself could be bent. The shaft that sticks out the front of the torque tube wobbles in it's hole when I spin it.

Thanks

James C

20180907_122730.thumb.jpg.68813cc8204834a6219f0f58e589d3c2.jpg

 

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The outer tube cannot be removed from the pumpkin. They are pressed and riveted togethetr.

To get the torque tube assembly out of the dif housing you have to pull the axles first. To do that you have to remove the spider hear pin and block. Push the axles toward the center and remove a "C" clip on the axles.

Once out to get the pinion and drive shaft out, you have to remove the ring gear carrier. Then remove the 3 bolys with nuts you see and then the driveshaft / pinion assembly will come out. You can then check the bearings. Watch out for the shims between the front pinion bearing outer race and housing bore - they are important to maintain pinion position.

 

A little wobble at the end of the driveshaft at the trans is permissible. An actual bent driveshaft is unlikely.

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"A little wobble at the end of the driveshaft at the trans is permissible. An actual bent driveshaft is unlikely."

 

That is correct.  The front of the drive shaft is supported by a bushing at the end of the torque tube.  The configuration is thus: the drive shaft inserts into the universal joint which is supported by a bushing at the tail end of the torque ball.  It is not supported within the torque tube.  The photo below is of that bushing:

102_0038.thumb.JPG.917b131eb5ee666b9272a5a36a71c477.JPG

Edited by kgreen (see edit history)
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The wobble is supposed to be measured at 1-1/2" behind the weld on the actual driveshaft tube. Max runout is .010". That cant be measured with the driveshaft and pinion in the housing of the torque tube.

A fairly worthless specification since the only way to measure it is when everything is totally apart..

 

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The other way to measure it is to allow a max of 0.006" clearance  between the bushing and the u-joint, then hope

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Okay. So the pinion bearings are pressed in from the back?? Whats the best tool you would you use to pull them out (without destroying them)? One of those slide hammer bearing puller kits or what? 

The plot thickens....

 

Thanks

James C

 

 

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The pinion bearings are not pressed in. There is a cage between the front double row bearing and the back roller bearing. Once you have the carrier out of the differential, take those 3 screws with lock nuts out - they hold the cage  and front bearing in place. Once the screws are out the driveshaft and pinion assembly will slide out. It mak take a  couple of blows on the trans end of the driveshaft to break it loose - protedt the end with something.

This is how it looks, those screws go into those holes you see.

 

I got a surprise to find that my pinion shaft had been welded to the driveshaft!  I was converting it to 3.9-1 gear ration.

DSCN1922.JPG

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Actually, the double row bearing is toward the FRONT and roller  toward the BACK. Note the shims behind the double row bearing at the front - critical.

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Thanks Don. You've explained it better than the manual and in much fewer words. I'm sure I'll have more questions as I dig deeper.

Thanks

James C

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10 hours ago, DonMicheletti said:

???  The cork gasket was for the rear cover.  Am I missing something?

No, just me...

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So, there is no pinion preload setting, but only a pinion depth setting. Does anyone have any spec range for side bearing preload?

Thanks James C.

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I've always adjusted for zero clearance.  Put a dial indicator on the ring gear and gently pry in each direction.  When it doesn't move  the pointer, you're set right.  The bearing caps must be torqued to check this.  

 

Bob Engle

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For what it's worth, the 42 shop manual is online and often goes into more detail than 1937. The axle is very similar to 37.

 

http://oldcarblog.com/manuals/1942/Buick shop manual/05-Rear Axle/page1.html

 

Side bearing preload and backlash is on image 9 and 10.

 

The reason there is no pinion bearing preload setting is that the fore/aft movement of the pinion is controlled by the front (ball) bearing. It does have preload, but it is internal to the front bearing. Both preloaded bearings are in the ball bearing assembly. If worn, the front bearing assembly must be replaced.

 

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The pinion location is determined by the shims between the bottom mof the bearing bore and the bearing. The bearing is forced against the shims via the 3 bolkts that hade tapered ends, pushing against the 3 holes that are in the spacer sleeve between the 2 pinion bearings.

I felt that it was a royal PITA to set up with the shims.

 

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How does one seperate the driveshaft from the pinion shaft, after i pumched out the pin of course? I dont have the factory tool but i do work in a fabrication shop. So I need some ideas.

Edited by 70sWagoneers (see edit history)

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Getting the pinion out of the driveshaft can be difficult.

I just grabbed the end of the driveshaft where it is welded and strong in a big vise and just drove the pinion out using a brass drift and a BIG hammer.

I was careful not to damage anything and was successful. It wasnt pretty.

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So you hammered on the bearings toward the pinion? I grabbed the pinion nut in the vise and "tapped" on the driveshaft while i pulled on it and nothing. Im thinking mine also need some heat. Don, yours may have been welded on there because someone thought it was loose. Did yours have a pin re-installed?

Thanks

James C

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There was a pin - doing nothing.

The rerason it was welded is that after I ground the weld out, I could pull that pinion out by hand. Somehow the splines had become wallowed out and were very loose. That is why the welding.

 

I didnt hammer on the bearings but on the back of the piion gear with a brass drift. That was with my spare.

 

Heat wouldnt hurt anything I dont think if you dont go crazt.

 

Why are you taking it apart? Bad bearings?

 

I might mention. When I had the torque tube assembly out, there was quite a bit of wobble at the end of the driveshaft, However there was no vibration when the car was driven.

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If you look closely at the spiline on this, you can see the spline wear.

 

I wondered how it might have happened since the spilnes are supposed to be tight

DSCN1966.JPG

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Mine was put together real well! After a couple of sessions of propane and a brass drift i switched to oxy acetylene. I hung the assembly from a forklift with the pinion up and a brearing seperator against the shoulder on the nut. Eventually I started to manually slam the driveshaft downward after i heated the driveshaft splines almost dull red. I went ape on it. The nut is toast so if anyone can recommend a good replacement or the correct search terms please let me now. And perhaps torque specs. But Ive got the bearings off!

Thanks everyone

James C

Edited by 70sWagoneers (see edit history)

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