Ask Dave Access

[Samuel Sperbeck]

I am fairly new to the forum, but I have read through all of the past posts in all categories except Ask Dave. How do I access that section to just read Dave's inquiries and his answers? I am replacing all of the bearings in the serpentine belt idlers because the belt was running one groove toward the engine and rubbing against the dampener, causing a squeal. I also ordered a new belt. I would like to add grease fittings to keep the bearings lubed. After getting the bearings out of the idlers I broke one and it was very dry. Any help would be greatly appreciated.

Thanks, Sam

[Doug Allman]

When you sign in to the website click on the   TECHNICAL  heading. ASK DAVE is in the center of this heading.

[Samuel Sperbeck]

Thanks Doug,

The Cat C-9 idler pulley must be different than the Cat C-12. My idler pulleys are held on by bolts with a washer under the head and centered  by a spacer on the inside. The two sealed bearings are pressed into the center of the idler without a gap between them. I don't see how grease could get into the bearings because the washer under the head of the bolt doesn't seal against the outer flange of the bearing and it seems to me that you would have to remove the seals from the bearings in order to get grease to the bearing balls. I must be missing something. Hopefully Dave will straighten me out.

Thanks, Sam

[Dave Atherton]

Samuel, the idler pulley we are talking about, will need a machine shop to drill a
3/16 hole on the hex end of shaft and depth of hole to come up in between the
two bearings in on shaft. Than drill a cross hole for grease to go in between the bearings 3/16.
Remove the seal on middle bearings facing each other so grease from shaft will get into
both bearings. Going back to beginning hole at hex drill and tap hole for grease
zerk. Note: new bearings without grease zerk will in most cases run about 80,000
miles. Dave Atherton Retired Cat Mechanic

[Samuel Sperbeck]

Thanks for the explanation,

I have everything back together because the belt arrived this morning. The belt runs true on all the pulleys and idlers. There are 56,544 miles on our coach so our idler bearings didn't make your predicted 80,000 miles, but even if the new bearings don't go another 50,000 miles they will outlive me. I have the tools to drill and tap for grease fittings but didn't bother to do it.

Thanks, Sam