Hi all

Just quick question that I'm sure someone has experience of.

I am about to change the bearings in a used gearbox/transmission. I have the sizes from the download page.

Here is question does anyone know what clearance the bearing should have. For example standard (cn) or c3 as some people use in places with more heat ?

Just want to save some money over the genuine BMW costs and get this gearbox ready before the other fails. 

Any help would be great. 

Another thought what brand is best koyo, skf, fag?

Any of those brands are fine and set up the shims as per the manual. I
f you don't have a manual send a PM and I will send a link for a free one.

Hi thanks

Yes I have the manuals from forum

What I was referring to was the clearance of the bearing itself when it is manufactured. I have read all the manual on the shim clearance an I think I understand that.

It's just the bearing itself. Hope that helps clarify. 

Thanks 

Smoll

The correct shims will give the correct running clearances on the bearings.

Ok

What about the ball bearing not tapered ones. Is the clearance between the balls and outer race standard or larger like a c3 bearing. 

For example can't remember exactly bearing number a 6203 c3 or non stamped which would be standard like used in wheel bearing.

I'm not brilliant at explaining myself.

Thanks for help though.

Smoll

From what research I can do on net the airhead gearbox uses c3 bearings so I suppose ks are the same.

Ball races are set from factory and cant be changed.

Smoll, you find at least two bearings marked C3 in Shoganai's tranny thread.
Have a look around, lot of pics......

This thread was also on this forum earlier (among a lot of other forums)
but I don't find it back.  


http://www.motobrick.com/index.php/topic,1808.msg9557.html#msg9557

Thanks guys

I had an old gearbox which I took the bearings off earlier following the advice you gave.

All the bearings were c3 as well so that's good news. 

I will keep everyone posted how I get on. It will be interesting to see what bearings are in the gearbox I am refurbishing. I will put number up when I have checked both gearboxes, hopefully they all same and it might help someone else on forum. 

Thanks for everyone's help. Forum is great.😀😀😀

Right

Now the snow has arrived I have been able to strip the 2nd gearbox.

These are codes I found on the bearings.

1st gearbox

Intermediate shaft - Fag 6303.E.C3 (both of them)
Output shaft - Fag 6204.E.C3
Output shaft - Koyo 6205R C3

2nd gearbox

Intermediate shaft - Skf 6303.ETN9.C3 (both of them)
Output shaft - Skf 6204.E.C3
Output shaft - Koyo 6205R

Does this sound about right to anyone. I can't find any bearings with the E in the code apart from the Etn9 ones.

It makes it confusing. I have confirmed they are all C3 clearance which is good. Now confused about the E marking. Are these different to a standard 6303.C3. 

Hopefully someone has rebuilt gearbox before and might know.

Thanks smoll

smoll1 wrote:
I can't find any bearings with the E in the code apart from the Etn9 ones.

It makes it confusing. I have confirmed they are all C3 clearance which is good. Now confused about the E marking. Are these different to a standard 6303.C3. 

From the SKF page.

E = Reinforced ball set
TN = PA66 cage, ball centred
TN9 = Glass fibre reinforced PA66 cage, ball centred

PA66 is the standard cage material for many super-precision cylindrical roller bearings and angular contact thrust ball bearings.

I saw that on Skf site. I have spoken to a couple bearing suppliers and I mentioned the E mark. They say the standard bearings are ok. I was a bit sceptical of these comments.

I can't seem to find anyone apart from Motobins/works.

They said it was an old code system. This just made me doubt even more. 

Surely some one sells what I need but not at bmw prices?

Could be that the "E" marked bearings is special made for the automotive industry.

That could be the case and makes sense