250 Pinion Bearing Installation

[rshim1]

I'm going through rebuilding of the rear axle assembly for my 250 and have come to a problem in the re-assembly process. I can not get the pinion shaft bearing at the gear end of rear axle gear housing reinstalled. Not wanting to force the issue and damage something I am asking for advice from someone who has successfully reinstalled the pinion bearing. Thanks in advance.

Roger Shimmell

[250GT]

Hi Roger,
last month I changed a very long ration 9x34 into 8x34.
There are two big bearings one on the sealside one on the pinionside
Both bearings touched a very stong circular clip see pic below.
If you have the bearings replaced by the same size,
I would not be nervus by using a piece of wood and cupperhammer to pressed them in ,
The main problem is to create the right contactpicture on the crown wheel,
I did not have enough cuppershims to reach the right result.
I let measure up the needed space and a prof. company machined an alu spacer.
Fotos show also lim. slip. diff too.

hope this info helped a bit.

cornelis

[rshim1]

Cornelis,

Thank you for replying. I have tried to drive the bearing in with the method you described but to no avail. The tolerance is too tight for it to go. I am afraid to force it in fear of doing serious ($$$$$) damage. Tom, has Francios made this repair? If so what does he recommend?

Roger

[250GT]

Roger,
you must fix one arm-see pic below- to the rearaxelalu-housing,
and fixate this arm in a vise.
its possible you put in deformation in the alu housing! by puting this alone in a vise
What came out must get in again , say my healthy brain.
low FRIXTION must be there. orther wise the new bearing is rotating in the housing
so measure up the old one ,and the inside of the housing this must fitt like a T.

Cornelis

[rshim1]

Hi Cornelis,

The bearing that I am trying to reinstall is shown in the photo below.

Roger

[250GT]

Roger,
thats the old R.I.V orginal bearing, you are showing,
If this make no noise you could use it again, but would use new ones in you're case. SKF (sweden quality) make them,
is this out for a long time?
if it won't get in something must have happend , not possible for me to find out here.
buy new ones and machine to the right size( lathe), thats what I can advice.

ciao
C.

[250GT]

P.S.
Forgot to say place clip first than go from the OUTSIDE(Neck or seal side) the pinion will be place later from inside.
ciao
C.

[tyang]

Cornelis,

Thank you for replying. I have tried to drive the bearing in with the method you described but to no avail. The tolerance is too tight for it to go. I am afraid to force it in fear of doing serious ($$$$$) damage. Tom, has Francios made this repair? If so what does he recommend?

Roger

Hi Roger,

I'm heading out to Pebble Beach, but will ask if Francois has any advice when I return.

Tom

[Colin Angell]

Pressing is always to be favoured for bearing installation, but in is difficult in this instance. I would suggest making a simple puller for this job, with a thrust washer to put the load onto the outer race only and a heavy section machine screw passing through the bearing to another plate on the outside of the case. You should be able to steadily tighten the screw and pull the bearing into place. Additionally you can put the bearing in your freezer for an hour first and gently heat the casting beforehand. Good luck.

[giovanni44]

Hello Roger,
Have you measured the new bearing and compared that measurement to that old bearing? Bearings have a bearing fit( sometimes refered to as a press fit )in their housing of only .00025" to .0005" at most and if that is exceeded you will have problems. Measure all the critical dimensions, O.D.,I. D. and width to be sure the new bearing will fit properly. If all is good then, be sure there are no nicks bumps in the bearing housing before proceeding. As another contributor has suggested us a stud & washers rather than pounding as drawing a bearing in with this method can generate a large amount of force. Cooling the bearing by refrigerating it and slightly heating the housing helps too. Regardless of method used, keeping the bearing straight is crucial,do not let it get crooked.

I hope this helps you and wish you the best of luck.

Giovanni44

[rshim1]

Hi all,

The bearing is now safely back in the housing. The solution I used was to freeze the bearing and heat the the housing. The housing was heated for an hour in my oven that was preheated to 400 degrees F. After the heated housing was removed from the oven I was able to slide the frozen bearing into place with no effort at all. Now I can get back to reassembling my rear axle.

Tom, did Francios tell you his method to this repair? I am curious if there was another way to solve this problem.

Thank all of you that offered input.

Roger