Moss Motors, Ltd

  I'm attempting to rebuild my TR3A differential. I need to remove the rear pinion bearing which is pressed(?) into the differential housing. I've asked it nicely, but it doesn't want to budge. Does anyone know how I get this out? 

  Thanks.

You are a brave lad!

Assuming the Dif. carrier is removed. the pinion must be pressed out, with a press. Hydraulic would be best. The bearing at the u-joint end is a tight press fit to the pinion shaft.

 

 

Once the drive flange is removed from the pinion and the internal diff carrier with crownwheel is removed the pinion can be driven out (rearwards) using a soft faced mallet or a piece of wood between it and the hammer. Be careful not to damage the pinion flange nut thread.  Place a lump of cloth on the bench/floor to catch the pinion and stop it being damaged when it flies out.

BE SURE TO COLLECT ALL THE ADJUSTMENT SHIMS THAT ARE BETWEEN THE SMALL(front)PINION BEARING AND THE SPACER. These are critical to get the pinion bearing pre-load correct when reassembling.

The front pinion bearing inner race and nose seal are then removed by tapping the outer bearing race forward from inside the diff casing.

Removing the outer bearing race is done by using a brass drift on the two exposed edges of the race - driven outwards (forward) from inside the diff case.

 

Cheers

Peter W

Peter W has it right. All I want to add is that when you are driving a bearing in or out with a brass drift you must move around the item you are trying to push. In other words, try hitting one spot, then move around the race one third of its circumference. Then go one more third, finally winding up where you started. This is important because if you don't do it this way the bearing race you are trying to remove/install will just want to tilt and wedge in the opening. In fact, in some cases, depending on the components involved, I've seen this wrong approach actually ruin the bearing bore or even crack the housing.

Additionally, you need to remember that even though manufacturing standards for roller and ball bearings are quite strict, the replacement part will never be just exactly the same.(Never say never. Who knows?) If you are indeed replacing the pinion bearings you will need to adjust both the backlash and the pinion preload and depth. Do you have equipment for this work? Do you have a manual, which indicates so? It's a mistake to believe that if a given position or number of shims worked before they will work now. The consequences of getting this differential/final drive together with bad engagement are howling noise and reduced life of the component.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Thanks MotorBill for the additional advice and notes on pinion bearing removal and refitting.

You are quite correct, the fact the orig item had 0.021" of shims does not mean a repaired installation with replacement bearings will need the same.

 

Peter W

Thanks for the input guys. I'm approximately 90% convinced that this project is too much for me. However, for curiosity's sake (and to further aid in the decision making process), I have a few follow-up questions:

 In removing the pinion rear outer bearing race, aren't we driving it rearward?

 I've located the slots in the differential housing which expose the edges of the race and I understand positioning the drift in these slots to punch the race out, but I don't understand how to rotate 1/3 the way around to keep the race from tilting.

  Now that I think about it, I'm at 93%.

  Thanks,

    Dick Tyson

  

Dick,

Yes indeed, I( forgot that the Triumph has just the two slots for brass drift clearance. Use the 180 method here.

Virtually any time you remove an outer race from a tapered roller bearing, yoou push in the direction of the "Big End", or the larger diameter.

Bill

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Dick,

Yes indeed, I( forgot that the Triumph has just the two slots for brass drift clearance. Use the 180 method here.

Virtually any time you remove an outer race from a tapered roller bearing, yoou push in the direction of the "Big End", or the larger diameter.

Bill

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Motor Bill

Churchill, the suppliers of workshop tools to Standard Triumph, made a tool for driving out these races.

It was a 3/4 round bar about a foot long.

One end was plain, the other had a rectangualar block attached that was 1" by 1.25".

 Attached to this were a pair of curved steel 'legs' that pivotted in and out on pins driven horizontally thru the rectangular block about an inch apart.  The legs were kept apart by a flat wire spring. The outward pressure of the spring ensured the legs remained in contact with the inside of the housing and the back of the bearing race.

Triumph employed this tool on a whole host of bearing areas in their cars.

The tool worked a treat in the Cox and Buckles workshop until some clown decided a plain 3/4 steel drift was needed, they cut the legged end off and threw it away  !!!!

If you can't understand my description I'll do you a sketch and email it.

Cheers

Peter W