I have a problem putting the serpentine belt back together properly on my 1997 XK8.

All the pulleys are lined up and I have a drawing that shows how to thread the belt.

Now, I have read the correct procedure to pull back the belt tensioner (so I can get the belt around the top / all pulleys) is to put a wrench on the left handed / reverse threaded bolt that goes through the idler wheel.

Trouble is, my left handed bolt continue to turn, leading me to believe it is going to break (hasn't yet). Also, it seems that a previous owner had put some weld on the bolt making it a little difficult to turn the bolt. I can grind the weld off easily enough, but am still worried about the bolt breaking.

I can tell there is some give in the tensioner, and of course would prefer not to replace it.

How can I pull back on the tensioner without breaking the bolt?

Thanks again in advance. The members of this forum are the best !

 

IIRC there's a 3/8" square hole cut in the tensioner, get your ratchet in that and give it a mighty pull. I'm getting on, so I cheat and use a small pipe extension.
Regards,

 

Unfortunately, the 3/8" square hole didn't come in the 1997 tensioner. (I've seen photos that show the square hole in later model cars.) At this point (midnight at the shop on a work night ... arrggghhh ) I'm thinking that what I could use is a new left hand bolt. Tried to find one online, and they only come with $50 idler wheels that I can't get until next week.
So, am wondering where could I get a metric sized left hand bolt that costs less than 50 bucks !!!???

It seems that of the choices fast, cheap and good, you can only get two out of three !

 

I would be slightly worried if I was able to turn the bolt on the pulley anti-clockwise with little resistance - that would imply that either the thread on the bolt, or the pulley assembly, has stripped. In either case, I think a complete new tensioner would be a wise investment.
When I replaced my belt, I remember a LOT of tension - I needed an extension bar to get enough leverage, so if it is turning (and - no disrespect - you are pulling it towards the centre of the engine in an anticlockwise direction) - there's every chance that it could just all come apart at the wrong moment.

 

DevonDavid...No disrespect taken and you are correct. I am pulling anti-clockwise and the bolt is turning, though it may be tightening as it goes......

I just wrote a long screed here about how I hate to spend another 100 bucks on the car (I am on the downhill side of a primary and secondary timing chain and tensioner replacement) and would look for a new bolt to bodge the old tensioner together. But I guess I ought to be thankful. This repair project hasn't cost me thousands of dollars (just thousands of amateur repair hours), though I am exceeding my self imposed budget by a few bucks.

Anyway, screed deleted. No sense trying to make an old part work when it's likely to fly off the car on a dark night, 50 miles from civilization. I am off to spend another 100 bucks or so for a new serpentine belt tensioner, as the current one does indeed look like it's on its last legs !

I'm filing David's advice in this thread under get with it man and buy a new part for gosh sakes !

(I wonder if there is an inexpensive belt tensioner available? Perhaps from a Lincoln LS ?)

 

Are you sure the bolt is actually done up properly? If it's turning then it's either stripped the thread or just not done up properly, and if the thread was stripped I'd expect the pulley to have fallen off by now.
I bought a used tensioner from ebay for about £20 recently, so that would be a good option if yours is damaged in some way.

 

Truck Graphics - File it under "Try Bladerunner919's Advice Before Spending Money".
Once you have made the decision to divert $100 or so from the beer fund to the car fund, there's nothing to lose by keeping on turning until it *either* gets tight, or falls off !!

 

Send me PM I have a couple of spare engines I can steal one off of with the bolt.

 

The bolt should tighten up enough to be able to use a breaker bar to move the tensioner arm. As already been mentioned it is probably stripped. It does take a lot of effort to move the tensioner enough to get the belt on. I had to disconnect one of the small hoses going to the overflow tank as it was in the way of where the breaker bar wanted to go. As I was working alone I ended up tying the breaker bar to something with 3 rubber bungee cords so I could use both hands to thread the new stiff belt.


Dave

 

I turned it until it broke. Off to the parts store for me. Thanks everyone !

 

If it's not on thing its another. To recap: I installed a new serpentine belt tensioner after installing new timing chain tensioners (secondary), camshaft "bush" (the thing that adjusts the adjustable valvetrain) and inspecting / making adjustments to the brand new primary time chain tensioners that were previously installed...And replacing a few other parts in this neighborhood of the engine.

The result: The engine runs beautifully, but the serpentine belt flies off. Not willing to wait until my wife or friend were around to turn the key, I put on the old serpentine belt (after destroying the new one) started the car, ran around to the front, just in time to watch the belt hiccup a couple of times on the alternator pulley and idler wheel, before destroying itself. Friends, you must think I'm mad because every time I impatiently try to fix something on this car (I'm really trying to get it out of my garage because I need the space - and want to drive it), I wind up throwing more sawbucks and Benjamins at it. Not wishing to search the cushions for more quarters I appeal again to the experts here for a solution.

Here are the clues:

The alternator pulley turns smoothly, though it feels heavily weighted.
The idler pulley turns smoothly.
The power steering pulley feels a little wobbly (but the belt seemed to track ok there).

Is it possible that the harmonic balancer isn't on far enough? (It's about 3/16" away from the engine plate.)

If I have to continue tightening the harmonic balancer bolt, which was tightened to spec (69 ft. lb. I believe), then pushed over another 80 degrees, is it possible that I might break the bolt?

Ideas? Serpentine belts are expensive (well 30 bucks) so I'm hoping the next one is the last one.

 

The torque is min of 268 ft lbs for the balancer. I use a breaker bar with a 4 ft piece of pipe.

 

Another idea. Take the fuse to the fuel pump out. Then crank the engine and watch the belt. You should be able to see what is causing the belt to come off.

 

You're right. I'm an idiot. I think that I was just enticed by the beautiful sound that engine was making after months of inactivity. Don't know if it was worth the 30 bucks though !

On a serious note, I wonder if you or the other folks out there could tell me how close the harmonic balancer should be away from the engine case.

Also, I gave the balancer bolt an 80 degree twist after it hit 69 ft. lbs. on the torque wrench...from experience, is it possible that another 80 degree - or more - twist would exceed the rating of the bolt (which is new)? When I hit max torque, is it possible to keep turning that bolt? (My big fear is of breaking the darn thing.)

 

The torque for harmonic balancer is 268 not 68. You almost can't break it

 

The belt was slipping off of the smooth idler pulley (on the passenger side of the motor). I put a shim (thick washer) behind the pulley and it worked a treat. Don't know if I lost the original shim during the project, but one problem solved. On to others ! Thanks for your help everyone.

 

I'm glad you posted this.. You just solved a mystery of my own from about a month ago.
I had the pulley changed and I suspected that it wasn't properly aligned. I even suspect a missing spacer.
As a result, the belt was rubbing along the edge of the pulley before ultimately snapping off.
I ended up putting a smooth pulley and it's now fine.

Old pulley


New Pulley

 

What did you use for the replacement - OEM an alternative Gates/Dayco etc?

I used Dayco 89016 and no issues with the belt, but it does run fairly close to the front of the pulley. There was no spacer behind the orginal.
Of course, what I should have done was to compare the offset with the old plastic tat before I binned it.

Thanks,
Mike

 

I didn't replace the idler pulley (while Anthony 8858 apparently did and could better answer). Just bored out a quarter inch thick washer to just over the size of the idler bolt (didn't use a micrometer, just a cone shaped drill bit and drill press) and stuck it on the back of the idler pulley. Actually, I think one quarter inch is too thick. Though the belt doesn't come off, it rides awfully close to the back of the idler wheel. I'm going to dig in my hardware box for a little thinner washer (high tech spacer !) and try that, just for my peace of mind. The belt position on Anthony 8858's idler pulley looks right to me. My belt now rides a little closer to the rear edge.

On a more holistic repair note, fixing the idler was the repair that allowed me to drive the car out of the garage for the first time, after depositing it there about a year and a half ago as a non-running project. Still a lot of fine tuning to go before calling this project a successful re-animation, but I can see myself behind the wheel !

 

Thanks TG.

I was just curious as your issue was the belt riding too far forward: Anthony's looks just fine to me too.

I wonder if the the alternator pulley tolerance is tight within 1/8" or so. Perhaps why the idler flange was later deleted.

Good to hear that the end is in sight - in time for summer