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Guest Message by DevFuse

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Stripped Idler Boss

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4 replies to this topic

#1 swelebny


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Posted 30 November 2005 - 09:30 AM

I freely confess I am an idiot. This is the first aluminum block I've ever worked on, but that's no excuse. I made several mistakes in the sequence of putting the cam belt back onto the engine after resealing an old oil pump and I stripped the block putting the 'toothed' idler next to the water pump back on. I've got the sequence down now, but the boss is stripped.

Every pulley that came off the engine had its bolt remain in the pulley. I know I didn't swap bolts around. But after the 'accident' the bolt being used for this idler pulley is awfully short. Only about 3/4 of an inch of threads stick through the pully, and there are at least several inches of thread in the block. There are also at least four or five threads left in the idler itself that don't make it through. Did someone pull a fast one on me when they were working on this thing over the years? The bolt looks much too short.

The big question now is what to do about it. I've searched the list and seen several possible solutions. The one I like the most is to buy a much longer bolt and use it (there's plenty of room). The problem I have is that with the first 10 or so threads are buggered. What's to get the threads of a longer bolt started in the good threads properly without buggering those too? Ditto goes for using a tap to clean the initial threads.... How do you get the tap started right through the bad threads, so that it taps clean into the good threads.

I'm half tempted here to just get the much longer bolt, slather it with T-88 epoxy, run it home and call it good. With 180,000 miles I've got a resealed oil pump, new water pump, new cam seals, new cam belt, and I think the car should now rust apart long before needing to open up the front of the engine again.

What do you guys think?


#2 ferret


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Posted 30 November 2005 - 09:54 AM

Replace the water pump then get the proper bolt. The threaded boss hole is part of the water pump casting. This is more common than people realize.

#3 a97obw


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Posted 30 November 2005 - 10:17 AM

If the boss is part of the water pump then I would agree, change the water pump. The OEM ones are very reasonable.

For future instances of trying to thread a bolt into a hole with damaged threads, a good trick is to use a 3 corner file on the bolt to file a notch in the first several threads longitudinally with the bolt. Then taker it easy going in with some fine oil. The notch serves as a cutting surface and allows a place for the trash. Thread it in and out a few threads at a time, like a tap. Patience!

#4 Handtool


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Posted 30 November 2005 - 10:59 AM

Replace the water pump then get the proper bolt. The threaded boss hole is part of the water pump casting. This is more common than people realize.


#5 swelebny


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Posted 30 November 2005 - 11:20 AM

You mean I didn't ruin the block!

I'll get the hang of these little cars yet. I'll get myself a water pump. To be honest, after messing up those threads I thought maybe it was time to hang up my wrenches. Obviously these cars are new to me, but my wife just loves the thing. Good to know I'm not the only one. I felt so bad to do the little car wrong.

I now know the right sequence of putting idlers back on that won't have me fighting so hard to catch the threads against the tension of the belt.With the tensioner compressed and the bottom passenger side idler off, it was a piece of cake. But by then I had buggered the threads.

The bolt through the idler only has about 3/4 of inch of thread protruding. That sound about right?


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