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idler bearings
- Thread starter Crankor
- Start date
You're in luck!
I'll give you the bearing sizes for all the pulleys including the tensioner and you can decide if you want to do them all. You can choose to use the bearings I did or find something comparable (but same size). I chose to go with Nachi because it's made in Japan and was the easiest to get.
The top and right pulley are the same bearing. Idler/tensioner pulley is different. Keep that in mind when reading the specs below. Idler/tensioner pulley has an opposite threaded bolt so left is tight, right is loosen.
Anytime a bearing is press fit, they typically cool one side (bearing) and heat the other (pulley) to create a slightly looser fit. That way when it cools it has a good interference fit. So when pressing the old bearing out, heat the pulley side with a propane/MAP gas torch in a circular motion...let's say 6 - 10 laps around the pulley. Then push the bearing out.
If you don't have a press, you can use sockets, washers, a nut and a bolt. When pressing the bearings out, I used a bigger socket on the side where the bearing comes out. The bolt can rest on the inner race as the bearing is being tossed anyways.
When pressing the new bearings in, find a socket that will sit on the outer race but still be able to fit inside the pulley. I've seen bearings pressed in using the inner race and that created premature failure (microscopic pits).
Make sure you have it all ready, so all you have to do it press it out/in because you don't want the heat to heat soak into the bearing and then you have a high interference fit.
If you do the method above, you'll be able to replace bearings a few times. If you do it cold, I'd say maybe 2 times and the interference fit will no longer hold but maybe by then you'll want new pulleys.
When you do use the socket method, keep an eye on the bearing to ensure it doesn't get pressed on an angle or it'll get stuck. If it does get stuck, you can get it out but there's a chance of the bearing getting damaged so be careful.
Goodluck!
Top Pulley
Original bearing: NSK 6301 DUL1
Replacement bearing: NACHI 6301-2NSE9C3
ID: 12mm OD: 37mm Width: 12mm
Right Pulley
Original bearing: NSK 6301 DUL1
Replacement bearing: NACHI 6301-2NSE9C3
ID: 12mm OD: 37mm Width: 12mm
Tensioner/Idler Pulley
Original bearing: NSK 6203 DUL1
Replacement bearing: NACHI 6203-2NSE9-C3
ID: 17mm OD: 40mm Width: 12mm
I'll give you the bearing sizes for all the pulleys including the tensioner and you can decide if you want to do them all. You can choose to use the bearings I did or find something comparable (but same size). I chose to go with Nachi because it's made in Japan and was the easiest to get.
The top and right pulley are the same bearing. Idler/tensioner pulley is different. Keep that in mind when reading the specs below. Idler/tensioner pulley has an opposite threaded bolt so left is tight, right is loosen.
Anytime a bearing is press fit, they typically cool one side (bearing) and heat the other (pulley) to create a slightly looser fit. That way when it cools it has a good interference fit. So when pressing the old bearing out, heat the pulley side with a propane/MAP gas torch in a circular motion...let's say 6 - 10 laps around the pulley. Then push the bearing out.
If you don't have a press, you can use sockets, washers, a nut and a bolt. When pressing the bearings out, I used a bigger socket on the side where the bearing comes out. The bolt can rest on the inner race as the bearing is being tossed anyways.
When pressing the new bearings in, find a socket that will sit on the outer race but still be able to fit inside the pulley. I've seen bearings pressed in using the inner race and that created premature failure (microscopic pits).
Make sure you have it all ready, so all you have to do it press it out/in because you don't want the heat to heat soak into the bearing and then you have a high interference fit.
If you do the method above, you'll be able to replace bearings a few times. If you do it cold, I'd say maybe 2 times and the interference fit will no longer hold but maybe by then you'll want new pulleys.
When you do use the socket method, keep an eye on the bearing to ensure it doesn't get pressed on an angle or it'll get stuck. If it does get stuck, you can get it out but there's a chance of the bearing getting damaged so be careful.
Goodluck!
Top Pulley
Original bearing: NSK 6301 DUL1
Replacement bearing: NACHI 6301-2NSE9C3
ID: 12mm OD: 37mm Width: 12mm
Right Pulley
Original bearing: NSK 6301 DUL1
Replacement bearing: NACHI 6301-2NSE9C3
ID: 12mm OD: 37mm Width: 12mm
Tensioner/Idler Pulley
Original bearing: NSK 6203 DUL1
Replacement bearing: NACHI 6203-2NSE9-C3
ID: 17mm OD: 40mm Width: 12mm
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