As the title suggests, the Idle arm for my AC compressor wheel flew off while parking, thankfully no damage as far as I can tell...is there a way to......uhm...re-attach it? No idea why it fell off but it did haha.

 

Depends what failed.

Bearing grub screw came out, and the bearing and pulley left the alloy arm.

Alloy arm retaining/pivot bolt came loose, NO nyloc nut fitted, oops, BUT, that adjuster rod should have kept it attached, sort of.

The alloy arm snapped, NEVER seen or heard of it, just saying.

The steel bracket attached to the engine came away coz the bolts fell out, OK, plausible, maybe, perhaps, but that adjuster rod should have left is dangling, and clattering around a tad.

You need a few beers, and look around, what came off?, what happened first etc.

Everything can be reattached, and simply, just slow down and look outside the square, its a Jag, and a V12, what could possible go wrong??

 

Sorry should of been more precise. Not the arm arm just the wheel.

 

The bearing assembly failed. It's replaceable. Normally on North American cars you'd have the air pump doing the job of that idler, so someone's deleted the airpump. You need this from Barratt or elsewhere. You'll have to have the old pully mounting flange pressed off the old shaft and pressed onto the new bearing assembly. There is a setscrew in the side of the arm that holds the old bearing in. Take it out, and the old bearing should come out. You may need to remove the idler arm from its pivot to get the old bearing out.
Jon

 

I dont see how that part fits or matches what is in my car? am I blind? lol this is very confusing Im about to just say **** it and run a belt direct from AC to crank, i have the belt No# here somewhere it fits alright. this whole idle arm thing has been a disaster I deleted the air pump years ago and had nothing but wobbly belts ever since.

 

The big end in the picture from Barratt fits in the idler arm. The skinny part is the shaft that came out with the pulley on your car.
Here's the exploded view.

#1 is the idler arm, #2 is the bearing assembly, #3 is the flange the pulley attaches to, and #6 is the pulley. On your car, the shaft pulled completely out of the base in the bearing assembly. If you look at the picture of your idler arm, you can see what's left of the needle bearings inside the base of the bearing assembly. #4 & #5 is the set screw and jam nut that hold the base of the bearing/shaft assembly in the idler arm.

If your belt wasn't running true, it's likely because the base of the bearing assembly was too far in or out of the idler arm. You can adjust it forward or back a little the get the compressor, idler, and crankshaft pulleys all in line. Then you clamp the bearing assembly in place in the idler arm with the set screw and jamb nut. You bearing was likely failing for sometime before it came apart, causing the pulley to wobble.
If you try to delete the idler, you will still have to figure out a way the adjust tension on the belt unless you like squealing belts.

Jon

 

Commonly called a "Water Pump Bearing", used for 100 years in various applications..

Memory, luv that stuff, that Idler one is a "5/8 assembly".

NOT a real DIY task, as that small hub needs a press, and I usually put a drop of Loctite on that shaft when reinstalling that hub.

Some replacements DO NOT have the small flat ground in the casing for that grub screw, great care needed to do that, and if you dont, the risk if the bearing coming out of the alloy arm is high. That grub screw is only tighten VERY CAREFULLY, NOT Groilla tight, as that will distort the outer casing, and what you have now is about a month away again.

 

I would of liked to fit the AC to the main pulley via the perscribed belt which I have and bypass the whole arm BS, the shop never did that and instead chose the arm route and deleting the air pump. So what you guys are saying is basically buy the part, then take the assembly to a shop with a proper press and do it right?

 

It had a wobble from the start, didn't think much of it for the first bit but that was a years' worth of daily driving im just glad it failed as I rolled into the garage and not 130kph on highway. The fan could of exploded the way it fell off.