Possibly bent brand new rotary shaft and Damaged Bearing?!? HELP!!

[makaveli07]

Hey everyone!

I'm in the process of rebuilding a 787. Old rotary shaft sheared the brass gear and is visibly bent (as seen in the pictures). I bought a new OEM shaft on ebay and a rebuild kit from OSD marine (Japanese Bearing).

I'm very nervous that i might have bent the new one trying to hammer the new bearing in, I used a rubber mallet and a bearing separator but i feel like it took quite a bit of hammering to get the bearing to seat all the way in, which makes me very nervous that i might have bent the new one!!

How do i check if it is bent or straight? visually it looks straight but is there a way i can check for sure?

Also how can i tell if i damaged the new bearing since i drove it in with the bearing separator which most likely technically drove it in using the outer race (lip) of the bearing rather than the inner.

Last thing i want to do is rip the motor apart again due to another sheared brass gear and a destroyed crankshaft, or am i overthinking this?

Any help is really appreciated!

Thanks in advance!!

 

[Tiggo]

You would have to chuck it in a lathe and use a
https://www.amazon.com/gp/product/B07RLTBND4/
to check for out of tolerance roundness.

 

[makaveli07]

You would have to chuck it in a lathe and use a
https://www.amazon.com/gp/product/B07RLTBND4/
to check for out of tolerance roundness.

I don't have a lathe unfortunately, also the link shows a fuel pump replacement ?

 

[Tiggo]

Oops sorry.
https://www.amazon.com/Toolrock-Professional-Indicator-Precision-Inspection/dp/B081GT88J8/

 

[Tiggo]

I don't know of any easy way to check to see if it is a little bent. It is probably fine.

 

[mikidymac]

The only thing you might have damaged would be the bearing. You should have been pressing it on from the inner bearing race, not the outer. Easiest way is put the bearing in a vice or bench with a hole and the inner race supported. Put the shaft in the freezer with some grease on the bearing surface then once cooled for a few hours tap it into the bearing.

Honestly with that rubber mallet you really couldn't have generated enough force to damage the shaft.

 

[makaveli07]

The only thing you might have damaged would be the bearing. You should have been pressing it on from the inner bearing race, not the outer. Easiest way is put the bearing in a vice or bench with a hole and the inner race supported. Put the shaft in the freezer with some grease on the bearing surface then once cooled for a few hours tap it into the bearing.

Honestly with that rubber mallet you really couldn't have generated enough force to damage the shaft.

I highly doubt I bent the shaft (might be slightly overthinking it) looks pretty straight to my eye. however you are right about the bearing as I feel like there is some super slight play in the bearing that i don’t like! I just called my dealer and ordered a new bearing which should he here tomorrow, $25 CAD for OEM bearing better safe than sorry. And i will probably take it to a local shop and have it properly pressed in to avoid problems! Or freeze the shaft support the inner race then drive it in as you said. Still kind of nervous about the possibility of bending that shaft lol

 

[makaveli07]

So an update:

I took the bearing off to while i wait for the new one to come in from the dealer , I did notice some slight "damage on the shaft". Shaft looks straight to my eye but I cant be certain.

Any concern from these pictures/ damage?

Thank you in advance!!

 

[mikidymac]

Nope. Perfectly fine. Just put grease on it next time.

 

[makaveli07]

Nope. Perfectly fine. Just put grease on it next time.

Got the bearing replaced With a OEM NSK bearing from the dealer. Had it pressed in this time using a press and the inner race and made sure to grease it well!. Looked at the shop manual and measured the deflection too! Looks to be within spec!. Last concern I have Is I froze the shaft in the freezer and tapped it in with a rubber mallet, seemed to take a good amount of tapping to get it in, is this normal? could it have bent due to the tapping lol? I made sure the seal doesnt bend either I placed a socket around it and tapped it in too and put the c clip. The shaft spins freely with very slight resistance, is this normal? Does this all look okay?

Thanks in advance

Really appreciate all the help!!

 

[mikidymac]

It’s fine. Stop worrying so much lol.