Belt tensioner bolt broke off
 

Loud tapping noise and belt squeel came from my serpentine belt slipping due to broken belt tensioner bolt.

Had several problems with my belt tensioner shock absorber bracket breaking in half. Right in the weak spot at the bolt nearest to the shock absorber.
Welded the bracket two times and it broke again.
Last time I welded an ekstra flat iron on top, and re-drilled the two holes.

Now the belt tensioner bolt broke instead. (I only moved the problem as it seems).
Seems like my serpentine belt is to short! Can that be the problem?

Parts on my van: 1994 E-350, 7.3 Diesel, Engine vin: M
Serpentine belt, F4TZ-8620-T (JK6-1118) lenght 111.4"
Belt tensioner, F4TA-6B209-EA

Old belt in the trunk: lenght 111.0"
The belt and tensioner was changed 6 months ago for previous owner by Ford dealership.

Do I have the right tensioner and the right lenght belt for this engine?????
If not please give me the right part numbers.

Got out the old bolt from the engine. Used a small angle grinder to cut a screwdriver slot in the bolt.
Just screwed it out easily :-bigparty

The bolt broke off because it got lose, and the belt load sheared it right off.

Installed a new 10mm bolt with hexagon head of same lenght as the old one. But with higher quality steel 12.9 (original 10.9 quality).
Torqued the bolt to 62Nm.

Where should the markings on the tensioner be?

As I can see, there are two sets of markings:
One has a squared notch and a rounded notch.
The other is a marked area.

On the notches, the arrow points to the inner side of the squared notch (left side of the notch, between the two notches).
On the marked area, the bottom line is barely inside the marked area.

Where should the line or arrow point when checking if the belt is correct?

4 more bolts later, I have this time, mounted the M10 hexagon head bolt with loctite 572.

Also I rounded off the seating surface of the bolt, so that it fits into the tensioner groove.

Next time this f...er breaks off I will drill out the threads and the tensioner. Then put in a M12 hexagon head bolt with a ny-lock nut on the back.

Oh! And the bolt broke again :-banghead

This time I tok out the complete holder for belt tensioner, steering pump, vacuum pump and AC compressor.
Managed to get it up and out without removing fan and radiator.

Once outside it was obvious what the cause of the problem was.

The seating for the tensioner and the tensioner itself did not have a smooth flat surface.
The center of the tensioner and the holder was protruding just enough for the tensioner to wobble to all sides. This wobling action caused the bolt to break off under load.
I used a file to even off the to mating surfaces and then ground to perfect match with grinding paste.

Mounted the tensioner on the holder with Loctite again, and then mounted the holder back on the engine, thight space but I managed.

Now I have been driving for a couple of thousand kilometres and the tensioner is still in place.

And the bolt broke off again :-arrgh

Took out the holder again, and this time I drilled it out to 12mm.
Also drilled the belt tensioner to 12mm.
Put in an extra long M12 bolt with a ny-lock nut and washer on the rear.
Mounted back in the holder with the belt tensioner in place.
Tight, but I managed it.

Now I have a belt chirping somewhere.
I overhauled the generator, and re-greased the sealed bearings. They were completely dry.
Tested vacuum pump, idler wheel, belt tensioner wheel, ps wheel and water pump.

And then there is the AC pump. My main suspect right now. When turning it by hand I can hear a faint metallic sound, probably amplified when belt is in place.
Any means of getting a drop of oil on to the shaft??

I will run the engine with AC on today to see if there is a difference.

Spray or drop some water on the belt, if the squeak goes away and comes right back, you just need to spray some silicone or belt dressing FOR SERPENTINE BELTS on it to quite it down.

Mine used to squeak, my 01 Sport trac used to squeak, but after a shot of silicone spray, they have stopped. Don't let anyone tell you that silicone will make the belt slip and you just can't hear it, that's bogus.

Problem of the squeak is now narroved down to either AC pump or PS pump.

PS pump has a lot of endplay on the shaft, is that normal?
When I take off the serpentine belt, I can push and pull on the PS pump wheel.

3x
 

I bought my 97 f250 two years ago and the bolt that holds it into the bracket on the engine has sheared off for the third time why is it keep happening

My problem was solved when I removed the shock absorber and tensioner.
Mounted in the original type tensioner without the shock absorber.

Turned out that the previous owner had replaced the original tensioner to a new "improved" type recommended by the Ford dealership.

Tension on the belt should be max 1 - 1.5cm on the longest part of the belt.
The longest free belt part between two pulley wheels.
Quite shure a workshop manual will give you the correct figure on tension.