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'03 Disco SE
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Discussion Starter · #1 ·
Has anyone replaced the bearings in the two idler pulleys on the 4.6L D2? Can anyone confirm part numbers for the new pulleys. The initial info I have is that the larger (80mm) pulley uses 6304 bearings while the smaller (70mm) pulley uses 6203 bearings. 6203 seems to be the industry standard for idler pulleys, but in this thread:

Idler pulley, replace or rebuild? - Land Rover Forums - Land Rover Enthusiast Forum

Someone claims that the 6203 wouldn't fit because the inner ring is too big. However there are no "standard" bearings that offer similar dimensions to the 6203 and I doubt LR would have custom made bearings. So I don't know whether to believe the post.

And before you ask, I'm replacing the whole tensioner alltogether - it slips when it gets wet so I think it's time.
 

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Before you consider replacing the belt tension pulley, first test and see if the spring is still good and will rebound to match up the two marks, if not, replace the entire belt tensioner.
 

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'03 Disco SE
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573 Posts
Discussion Starter · #3 ·
Mike - I'm replacing the entire tensioner assembly including the pulley and the swingarm. It'll be an all-new piece. I'm only doing the bearings in the two idler pulleys because the bearings will get here quicker than a new complete assembly.

The spring has gone soft - it's OK in dry weather, but the minute I drive through water of any "real" depth the belt starts to slip. My battery light comes on and my voltage (as measured by UG) drops for the next few seconds. Yes it's my daily driver but considering the amount of rainfall we had this summer I was driving through 12"-18" of water on an almost daily basis.

This weekend will hopefully be the big day where I can rebuild my oil pump, replace water pump and alternator, replace tensioner and idlers, and various other bits on the front of the engine.
 

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'03 Disco SE
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573 Posts
Discussion Starter · #4 ·
And I think I got to the bottom of my bearing question. The guy in the post who claims the 6203 won't fit in fact used the 6203-12. This is a designation given to the 6203 pulley with a 3/4" ID (~19mm) which would explain the difference in size.

I ordered them - I'll post how it went. $20 for 2 high-end Japanese bearings is certainly better than $60 worth of new pulleys.
 

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Mike - I'm replacing the entire tensioner assembly including the pulley and the swingarm. It'll be an all-new piece. I'm only doing the bearings in the two idler pulleys because the bearings will get here quicker than a new complete assembly.

The spring has gone soft - it's OK in dry weather, but the minute I drive through water of any "real" depth the belt starts to slip. My battery light comes on and my voltage (as measured by UG) drops for the next few seconds. Yes it's my daily driver but considering the amount of rainfall we had this summer I was driving through 12"-18" of water on an almost daily basis.

This weekend will hopefully be the big day where I can rebuild my oil pump, replace water pump and alternator, replace tensioner and idlers, and various other bits on the front of the engine.
Don't forget to replace the timing chain set at the same time if it hasn't been done yet.
 

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you can get a metal 70mm pulley from Rovahfarm for $20. I had to do that because mine was plastic and I couldn't replace the bearing.
 
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