Auxilliary drive belt tensioner pulley

[937carrera]

I'm in the middle of doing a timing belt kit swap, having noticed a bit of a whine from the cambelt area and not knowing how old the belts are.

I have identified that the noise problem is the idler / tensioner pulley for the alternator / aircon / power steering pulley.

I looked around and it seems that it isn't possible to get the pulley by itself, you have to buy the complete tensioner. Not wanting to pay the price for a new tensioner when all I need is a £3 bearing I have bought the correct bearing, a 6203 2RS, and am about to try disassembling the pulley to replace the bearing.

I assume the pulley is in two halves and it's an interference / radial groove pin arrangement. Knock the three pins out, replace the bearing and reassemble. Before I give it a go I wondered if anyone had any experience of doing this.

Grateful for any advice and I'll post updates along the way.

[alexperkins]

This happened on my mates albeit we replaced the tensioner in its entirety

Bearing should be replaceable though. Have you tried pressing it out?

[937carrera]

I think it's probably quite a common problem, which is partly the reason why I decided to try a functional repair rather than replacement.

I don't think the bearing will simply press out. The diameter of the bearing is 40mm and what you can see is about 36mm of it, it seems that the outer race is encased in the two halves of the pulley wheel and held in place by the inner lip.

[alexperkins]

Oh I see now. Phone screen was a bit dark! Yes that looks right

[937carrera]

Here we go, all in little pieces. It's all just an interference fit, the outer race of the bearing on the pulley and the pins to stop the two halves of the pulley moving differently.

I knocked the pins out with a couple of steel drifts, one oversize to get the pin flush with the pulley, then one the right size to knock the pin out. I then used a steel chisel to gently pry the two halves of the pulley open.

The bearing was simply knocked out using a couple of sockets

I just need to await delivery of the new bearing now. Looking good I might even get the wire brush & black paint out to clean things up properly

[alexperkins]

Happy days what are you replacing the rivets with

[937carrera]

I was simply going to re-use as they seem to have neither a lip put on or any retaining groove. Maybe add a bit of Loctite for additional security ?

[937carrera]

The bearing arrived and so I have reassembled the pulley. The bearing is definitely an interference fit on the pulley wheel so the rivets don't seem to do anything to hold the assembly together, more to stop the two halves turning at different rates. I assembled by hand, used a vice with wooden blocks to compress the discs onto the outer race of the bearing and used a bit of loctite for additional security.

Here's some pictures:

Part assembled - not properly lined up or home but you get the idea



Almost finished job

[alexperkins]

Looking good.

What's make was the new bearing?

[937carrera]

SKF, bearing 6203-2RSH

For what they cost, may as well go for a decent manufacturer, even if the bearing shields are black instead of red.