FXF

2000 Cherokee 4.0, new to my daughter, I get to turn wrenches.


Trailered Jeep home yesterday from auction lot and as I had noted in inspection the serpentine belt was in need of replacement. Installed new belt, verified the path and in grooves correctly, tightened the adjustment idler, and started engine.


Belt immediately works off the front side of A/C compressor drive, and then off the front of Power Steering drive. Released tension, corrected belt engagement, retightened belt, (slightly tighter this time), and started engine again. SAME PROBLEM, belt off front of both A/C and P. S. drives.


Checked with a steel straight edge alignment of crank to P.S drives, then the A/C to P.S. drives, and as best possible the water pump to belt driven fan drives, all of these seemed to be within the leather.


The only item I could not check effectively was the alternator drive to crank or to driven fan.


Since all of the drives for major components, (A/C, P.S., adjustable idler, crank, water pump and driven fan) are bolt in place design I don't think they can shift, the only suspicious item is the alternator.


With a little slack in the belt I can manually rotate it around all drives and it appears that the belt coming from alternator to go around the driven fan pushes towards the radiator and causes the belt to slide to front of the driven fan drive and then slips 1 or 2 belt grooves off the front of A/C drive then same around adjustment idler wheel and pushes off the P.S. drive same amount. When running it comes off these same 2 grooves and no more.


Sorry for the long description, but I'm stumped, and can only think the alternator drive is out of alignment, but can't figure how to adjust it.


Any thoughts or remedies are sought.


Thanking you in advance.

RTorrez1

I would double check the harmonic balancer pulley. Make sure that it isn't coming apart. It is a very common problem and it will cause the belt to come off.

SteveMongr

If the harmonic balancer is worn out it can shift or wobble, causing issues with the belt.
Did you use a diagram to route the belt? As a rule, a smooth pulley gets the back side of the belt only.
A picture would help, we may be able to notice something from it.

Turbo X_J

If the alignment of all pulleys is correct and nothing is seized up then try this tool, 180-200 lbs for a new belt, 140-160 for an old one. Correct spec will be a hellalot tighter than any normal person would expect.

FXF

Thanks for the immediate feedback. The belt diagram is long gone from this Jeep, but I followed the correct path, grooved to groove, flat to belt back.

Interesting finding on belt, the one listed for this motor is 4" to long, but the one that fits is the RIGHT hand drive belt.

I'm going to try the torque setting first, but in case it is the harmonic ballancer is that what the belt driven fan is attached to?

Any other thoughts are appreciated, will try for pixs also.


Fx

Turbo X_J

2000 Cherokee 4.0

SteveMongr

Great diagram just posted..
Crank pulley is the harmonic balancer.
Something is fishy about having to use a RH belt. Perhaps something was modified. Need some way to compare yours with known stock.

FXF

Turbo X J's diagram was the key. It was completely different from the 2 that I had been given by AutoZone and O'riley's. This also solved the question of RH drive belt. The loop from alternator up over the A/C was missing from both previous diagrams. All is well now and I understand why the "extra" 4"of length is called for.

Jeep is working fine, no odd belt issues, just keeping fingers crossed as the crank harmonic damper looks like a radiator pull to ge to.

Thank you again for the quick feedback.

Fx

Roadrunnr72

Shouldn't have to pull the radiator. I am I the middle of an engine rebuild, while the engine is still in, and didn't pull the rad to get the crank pulley off

Glad you got it figured out.....RR

Turbo X_J

You provided good info, glad it worked out for you.