1953 Drivetrain question

[Dadstruck]

We have a 1953 chevrolet first series (small rear window) truck that had a broken driveshaft. We got a new front spline welded onto the old shaft at a driveline service. The front of the differential housing near the rivets that fasten the torque tube to the diff has the 3 bolts with locknuts that anchor the inner race of the pinion shaft bearing(?) I believe that these only serve to keep the race from spinning(?) Trouble is, now that Dad has reassembled the shaft into the torque tube, when he tries to anchor down the 3 bolts they do not strike anything. Also, the driveline service sent back a long front bushing, when the original ones that it had were the two smaller ones. The front bushing right behind the front splines got thrashed when the shaft sheared, and I had to cut and re-weld the front of the torque tube to get the bent spline section out. Question is, is it critical to tighten down the 3 bolts? He mostly drives around his farm at 5 MPH. Are the 3 bolts only in '53s and not in '55? Could driveline shop have put a later pinion shaft bearing in that has no recessed groove for bolts? ALL INFO APPRECIATED as dad is truckless!

 

[coilover]

Where are you located? We have done several streetrod 47-54 trucks so there is a pile of running gear parts left over. Getting a whole rear assembly still intact might be the best way to go. Were near Dallas so if you can come by I won't sell you one but I will GIVE you one. I also will not ship anything since the time it takes interferes with the shop work.

 

[f4fantm2]

I've got one from a '50 truck you can have if you'll come and get it. I am in central Kentucky.

 

[brit 50]

Hi there, ive just re-built my rear end and can tell you this, the three bolts with lock nuts are there to hold the front pinion bearing in place, they are ultra important, they do this by the points of the bolts forcing a steel ring against the bearing, the ring has a tapered edge which the bolts hit and in turn push the ring into the bearing.

When you slide the pinion shaft into the diff housing you need a shaped piece of flat steel that goes in between the pinion gear and the rear pinion bearing, as you tap the shaft home this tool makes sure the rear bearing is seated in the housing as without it, the front bearing hits home before the rear one, as you do all this ensure the whole assembly is nose down, ie the diff end up as high as possible and the gearbox end down as low as possible, this will ensure the ring that is behind the front bearing will drop forward and you can push it home with small screwdrivers through the three bolt holes so that only the tapered edge is visible through those holes, then as you wind the bolts in they will hit the taper and push bearing tight into the casing.

If you check out the manuals that are online at some sites you can see this tool, its easily made out of approx 1/8 flat steel and it is like a fork with two prongs, it fits snug over the pinion shaft between the pinion gear and rear bearing, all it does is take up some of the play of the rear bearing on the shaft.

As for the front bushing, dont worry, its designed to support the shaft in a different place that has no wear on it, install it after you fit the shaft but check it fits the shaft before you put the pinion shaft in, put a new oil seal in the rear of the bushing and grease it before tapping it home with a big socket or thick bit of tubing, check that you have'nt damaged the edge of the bush after hammering home by sliding your yoke off the back of the gearbox onto the splines, i peened the edge over slightly on mine and needed to file a chamfer on the bushing to get the yoke on the shaft,

Bit long winded answer but you will trash your diff if this isnt done properly within seconds of running it!

good luck

Neil
________
Marijuana test

 

[Dadstruck]

Follow up Question to Neil

Hi there, ive just re-built my rear end and can tell you this, the three bolts with lock nuts are there to hold the front pinion bearing in place, they are ultra important, they do this by the points of the bolts forcing a steel ring against the bearing, the ring has a tapered edge which the bolts hit and in turn push the ring into the bearing.

When you slide the pinion shaft into the diff housing you need a shaped piece of flat steel that goes in between the pinion gear and the rear pinion bearing, as you tap the shaft home this tool makes sure the rear bearing is seated in the housing as without it, the front bearing hits home before the rear one, as you do all this ensure the whole assembly is nose down, ie the diff end up as high as possible and the gearbox end down as low as possible, this will ensure the ring that is behind the front bearing will drop forward and you can push it home with small screwdrivers through the three bolt holes so that only the tapered edge is visible through those holes, then as you wind the bolts in they will hit the taper and push bearing tight into the casing.

If you check out the manuals that are online at some sites you can see this tool, its easily made out of approx 1/8 flat steel and it is like a fork with two prongs, it fits snug over the pinion shaft between the pinion gear and rear bearing, all it does is take up some of the play of the rear bearing on the shaft.

As for the front bushing, dont worry, its designed to support the shaft in a different place that has no wear on it, install it after you fit the shaft but check it fits the shaft before you put the pinion shaft in, put a new oil seal in the rear of the bushing and grease it before tapping it home with a big socket or thick bit of tubing, check that you have'nt damaged the edge of the bush after hammering home by sliding your yoke off the back of the gearbox onto the splines, i peened the edge over slightly on mine and needed to file a chamfer on the bushing to get the yoke on the shaft,

Bit long winded answer but you will trash your diff if this isnt done properly within seconds of running it!

good luck

Neil

Neil, Thank you! I will try to relate all this to 79-year old Dad via phone who is 1200 miles away as he tries to work on this in a drafty barn with poor light......

 

[vwnate1]

Wow ! I take one lousy day off to take SWMBO & our Foster kids to the beach and you guys get into all sorts of mischief

This is why I always chicken out and buy a used Torque Tube assy. complete when the ring gear or pinion bearings give up ~ it's simply too much labor .

Go get that free one , bag it well and ship it to your Dad via Greyhound Bus , it's cheap .

I'm still wondering how you broke the driveshaft !

 

[brit 50]

It was a bit of a long answer but its not too big a job, give it a try and see what happens, if you are going to get the used diff then you got nothing to lose!
________
Anal Amateur

 

[Dadstruck]

Followup Question for Neil and/or Nate

OK, so I read Neil's e-mail to Dad, and it helped!. He got pinion shaft front bearing tapered collar set up so pointed bolts locked it in. Neil's mention of the shaped piece of thin steel got us confused though. Does the rear pinion shaft bearing slide into an interference-fit receiver in diff housing? How does the shaped steel tool guide it in without ending up being captured inside the diff?

Thanks!

 

[brit 50]

Sorry for late answer, the shaped steel tool is like a big flat spoon with a u shape slot on the round end, it fits in between the pinion gear and the bearing just in front of it, this big bearing moves up and down the pinion shaft and the tool forces it away from the gear by only 1/8 of an inch or so, but it also pushes the rear bearing (the one nearest the gear) home into the housing, then as you slip this tool out and continue to tap the pinion gear into the housing the front hits home.

http://chevy.tocmp.com/1948_51truckshop/51ctsm0409.htm

This is a link to the online manual showing the tool, easy to knock up with a bit of sheet metal, not hardened or anything trick, its just a thin spacer with a handle,

Good luck
________
Plymouth Belmont

 

[Dadstruck]

Last Question for Neil!

Neil, thanks for your reply. The spacer fork makes sense now. And the Keith Hardy website is fantastic. We did not know about the spacer fork, and did not use it. Dad estimates rear pinion shaft bearing is seated home EXCEPT for last 1/8" that spacer fork would have provided. He has driven truck around slowly with no audible problems, as it is his only means of transport. Can he leave it well enough alone, or is that last 1/8" critical? Will pinion gear rub on bearing and cause a problem?

 

[brit 50]

Well i think its a case of just suck it and see, if its running ok with no noises then we can only hope eh! Nate will probably have a better idea if its ok as he has far more experience than me, as long as the three bolts are locating on the shoulder of the bearing retainer then nothing is going to fall out. just make sure the ring was pushed forward so that you can only see the edge of it through the bolt holes, ie; if you look through the holes yo will only see the edge of the taper at the front of the hole and you can poke a screwdriver clean through the hole past the retainer, not the retainer blocking up all the hole. it pushes allmost past the hole, that way the bolts will lock it fully forward as you screw them in.

Say Hi and good luck to your dad, he's a game old chap for doing all this in a barn on his own at his age. Respect to him
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Fisting Granny