Hope someone can help- I bought a '90 stick shift F-350 7.3 International diesel pre power stroke for the only reason, and that is to haul a 23' gooseneck- which can pull 2 of my Austins on it. Total weight of both cars 2800 lbs.

Have a '94 F-150 6 cylinder and have put 260, 000 miles on it and it is the best damn truck out there- not one problem. I thought all Fords were made equal.... how wrong I could be. I have had nothing but problems with the F-350.

My problem now is that I keep going through alternator belts. The belt that runs to the water pump, and not to the vacuum.

They have been brand new, not overtightened. Have checked pulley for imperfections and the alternator is good.

I use the F-350 to travel 6 hours each way, and it is no fun being stranded with a fully laden gooseneck.

Could it be the crank ? Any suggestions on what to do is highly appreciated, before I get out the dozer and bury the truck.

I am on the AL/GA state line in west GA and have been unable to find any folk out here who know diesels.

 

Is everything aligned correctly? What about the possibility of a lose shaft on the alt pulley? I had a 7.3l that did the same thing cause the shaft was slightly worn (just enough to wobble at decent rpms).

 

I'm new to Ford IH diesels, but I have four trucks with Chevy 6.2 diesels. I had the same problem with two of my early 6.2s, and now I just bought an 85 F250 with a 6.9 I.H. and it looks to have the same problem. If you look at your alternator belt when the engine is idling, facing the front of the engine and looking at the left side of the belt, does your slap like crazy? The belt on my 6.9 does, but I haven't driven it long enough to find out if it's going to be a problem. On the Chevy 6.2s, it WAS a problem, seems to be only on the diesels. Some time around 1985, Chevy (G.M.) updated the drivepulley that bolts to the crankshaft dampener to a rubber-loaded unit that absorbs belt-shock and does away with the alternator belt slapping like crazy. Don't know if Ford/IH had, and/or fixed the problem. Also don't know if this has anything to do with your problem?

 

When you look at the front of the alternator, look at the ends of the little fan blades to see if they are polished. Mine was running a little out of line which caused the belt to jump at idle because it was rubbing those blades. At higher speeds the belt would break or jump off the pulley. A little fooling with the adjustments ( I used a washer spacer) got rid of this and solved the problem. I have had three alternators on the motor, and only had a problem with one of them. Plowing snow seems to be hard on the alternator, but I have a 130 amp on it now and all is well.

 

The alternator belt on my 7.3 slaps like crazy. Its tight though and I haven't had any problems because of it. From what I've read it seems to be a pretty common occurance. I've read of people making idler pulleys to correct this but for me it hasn't been a problem.

 

Yeah, they're all "slap happy" at idle but it goes away when you rev them up. Does the alt. have the right pulley on it? The rear belt V should be bigger than the front v. I've seen some with just a regular double groove pulley and they don't let the belt ride deep enough in the V. Just a thought.

 

Thank you for your advise and a Merry Christmas to you all.
I have tightened the alt to reduce the amount of 'slapping' that I originally had- funny though when it was 'slapping' it ran fine and then when all the belts were replaced the problem occurred. I am replacing the alt and the pulley to see how that goes, rather than use the existing pulley. I do not know if the pulley that I have is the correct one, since I just bought the truck and have been having these problems from day one. The rear pulley is bigger than the front- to answer your question Spectramac.
Mhalter- when I first got the truck the belt was slapping and it seemed fine- the minute I replaced the belts I have had problems with them.
Fire Marshall- as far as I can see all is aligned properly, and there are no marks in the pulley that I can see.
Dave Sonaugle- the blades seem fine, but I am going to replace the alternator in the morning with a new one, although I do not believe that this is the main fault.
jdemaris- when I look at the alt front on it does slap slightly, but it did to begin before I replaced the belt when it ran fine.

Guys you have indeed been true petrolheads with your advise. My main issue with this F-350 is that I bought it to run me from Atlanta to Savannah where I pick up 2 cars at a time that I import from England and do not want to have problems when I am fully loaded with a 23' gooseneck, 2 cars and a crate of engines. I am going to run the truck for a 1000 miles before I can consider driving to Savannah docks to see if I can cure the problem. Also, Spectramac I am looking to move back to WA state in the spring of next year and need the truck to be able to make the journey.

Do any of you think it could be a problem with my crank ?

Spencer

 

When I got my last set of belts, I went to Napa. When we got to the Alternator, he asked me if I wanted the heavy duty belt. I said, "heavy duty? Hell yeah!" He gave me a solid belt without the little cog marks in it. I put them all on and they haven't given me a lick of trouble in 4 years.

 

Have been following this thread for awhile now- just wanted to add my two cents.

remember the need for the dual mass flywheel- this thing is kicking out bigtime torque pulses at really low rpms, and that little bit of rubber is just the middleman.

Its not your crank- - if it was your crank all the belts that ride off of it- and the crank pulley itself-would be all hashed- torn up belts and the pulley would erode

plus as many miles as you drove the oil seal would be toasted by now.

I know when we set lovejoy couplers up- you would look at it- and the damn thing would be aligned, but would squeal like a pig when turned on. Once you level the thing out, it was probably only .15 inch off- it would be quiet as a mouse. SO maybe if everything looks okay to the naked eye it still might not be, it still might be a little bent or- as if someone previously hammered on the pulley or some other foolishness that can go on when it is not your truck and they didn't care about fixing it right. This should be an easy fix- ten bizillion of these trucks out there and there is no shortage on alternator belts.....

 

But seeing what he is doing he wants it fixed right. Since the alternator drives the vacuum pump that is not a good belt to lose with a load on and have next to no brakes. And after being an OTR truck driver I also know it will happen in the middle of nowhere 100 miles from anything, probably at night in the rain.
Since you have checked all of our ideas I think my next approach would be Spectramac's with the heavy duty belt. Each alternator I have bought I had to reuse the pulley off my old alternator on the new one. I now remember that one alternator I had it was like the pully went on the alternator shaft to far. The belt rubbed the cooling fins on the alternator which caused the belt breaking. I took the pulley off and put a shim washer behind the pulley and all was well after that.

 

Dave, MRZ and Spectramatic thanks.

MRZ, I agree with it not being the crank and now know for sure. I pulled the alternator and thoroughly inspected it. The blades were moving like a Sat night drunk and also noticed that the blades had been hammered on with nicks in them, also the alt was a 65 amp and I bought a 100 amp alt which the computer showed. It seems the old shaft was out.

Most of this was not seen whilst in situ, but it is so much clearer with the alt removed. And you are right Dave, when I have the gooseneck hitched with a couple of cars the last thing I need is failure- so far so good and have not been stranded.

Also MRZ, you mentioned foolishness I think that much had gone on with this and more fool me for not detecting it before. Also, Spectramatic I may go with getting a Heavy Duty belt- at the moment it has a new alt and belt fitted and see how that goes. Rack up 500-1000 miles locally and then know for sure that the problem has been fixed.

I really appreciate all your help and I buy trucks for their purpose as oppossed to any other reason. I am not interested in its color or options so long as it does the job. My living is based on importing tiny Austins from England and need a truck that performs well. When my truck is down it costs me money.

Wish you all a very Happy New Year- Spencer

 

My 7.3 does it too! What or if you did fix it ,did you do. Thinking maybe putting one belt kit if they make it?