This is in a 79 brigadier , how does this fan drive work or supposed to work , cuz this one isnt working.hopefully these pictures are good enough for some help
Can't really tel what it is from the pictures. Is this a new to you truck or a customer's? I'd be just making a wild guess that it would be an air operated clutch. Could be air applied or spring applied and air released. Are there any air lines connected to it or the mounting bracket? Many trucks had an air line going to a valve on the engine in the water manifold or maybe thermostat housing that turned the fan clutch on and off. Sometimes this was done directly and other times there was a electrical sender that controled an air solenoid that turned on or off air to the clutch for the fan. Any chance there is a tag somewhere on the drive or housing somewhere? Even a partial name might help identify it.
This looks shade-tree to me. Most that I've had 4 lock bolts to loosen the screw operated tensioner. Can't say I ever seen this set up. Sorry.
Maybe some different views from different angles?
can`t be sure but it looks like a bendix viscous drive to me
This is owners litter truck couldnt get a good pictures it was oveheated at this point i just janmed my phone in there i didnt see any tell tale air lines. This truck is only one year younger then me lol.
Yeah i will try in the morning when its cold
Possibly i will try finding some info on those for that era, sounds like a good place to start as any.
Ok could this be an oil shear fan clutch? Never heard of one before seems to use engine oil to engage and disengage ? How i dont know gonna look for some info
Found kits for them to rebuild oil shear clutch but absolutely cannot find any info or pictures online i dont know anyone with old Detroit books , not sure if the clutch is made by DD or someone else, i have a hankering this is what i have guess i will just have to wait till morning when i can get a better look at it .
theres a guy on the jot website glen akers who seems to be up on old detroits if you can get on that site look him up
Is jot short for something
sorry about that ( just old trucks)
Those years the Bendix FD-1 and FD-3 were very common on Cat, Cummins & Detroit but those are obsolete no parts available. The other air hub was the Horton S & HT/S models. If it is a viscous type that may be a problem too. On most of the old stuff like this issue it becomes an updated repair.
Yeah it is a clutch type it freewheels, i found those models you mentioned and looked thru them all ,nothing looks like this thing, asked boss man if this truck was all original , it is minus one overhual. Cant find any pictures of what is called an oil shear fan clutch at all just the repair kit that has seals and what looks like wet clutch disks. Havent gone back to it yet boss man said it was a gallon and a half low on coolant and he was gonna try it again, i have my doubts but we shall see.
Ok gallon and half low on coolant after sitting overnight ran fine all day till the top rad hose blew up, orielly auto parts has this hose in stock in there georgia pdc 33 bucks will be here tommorrow evening. I think it was air locked i replaced lower rad hose on it and this was first time it had been run. Gonna take and post some better pictures of this fan drive and figure put how it works because it bugs my brain that i cant even find a picture of anything remotely similar. This truck and the other litter spreader are going to be sold when he can get another large case spreader. If money was no object i would buy it shorten the frame back up fix it all up nice pretty with a lift axle on it and give it back to him , this old truck was his very first lowboy tractor then it was a dumptruck now it spreads **** and oil in the fields lol
Ok so the part i have circled in below picture is the fan drive, it is a large circular housing behind the pulleys , it has oil lines running to it . The way the housing looks it could very well have a couple wet clutch plates in it like shown in the repair kits , im not quite sure how it works cuz im way to busy on trucks to investigate a 1979 farm truck at the moment. Fan drive does seem to be working correctly , the cuase of my overheat was definitely an air lock when i did lower hose, just did the upper hose and proper test drove it screaming around a field for 30 minutes, then topped of coolant when done . My question is this a dd assembly or is it made by someone else my curiosity has to know lol.
Could it be a Rockford. There was another one back then I cannot recall the name. For the application take it apart and find a way to make it run all the time.
Rockford was the first thought in my mind also.
Well if it is bast@rd GM or Ford will step up to use it in their trucks. IIRC I have seen one of those before but not in a truck.
All My Detroit books are early to mid 1970's and the only fan drives in them are the basic direct drive units and one they refer to as Thermo-Modulated that appears to be a heavy duty version of what would be used on say a 1990's Ford pickup truck among many others!
This will be a Rockford Oil drive, these things were popular for about six years then just went away, J U N K Junk. Try to find a yard with a different fan arrangement or you may end up building a fan support for a conventional viscous fan. We had three of those on 1980 GMC Brigadiers, what a PITA to work on. Should be a fan stat type arrangement for the engine oil application side.
Another point, these were built EXPRESSLY for GMC, they are not on other manufacturers trucks. Operates like a torque converter.
What did I say, just like that gutless 3116 cat.
Might be similar to what Cat used on the first 769 Haul trucks. I tried SIS and a few other places but could not find anything about the Cat ones. I seem to recall they were gear driven off the front of the engine, cam?, crank? or some other gears up front. As I recall they had a few gears like a speed reducer in them. Then there was like you say a torque converter or more correctly a "fluid coupling", difference being there was no stator like a converter would have. The control for it was a temperature actuated valve that controlled the amount of engine oil that was put in the the coupling, more oil faster the fan would spin. I believe there was an orifice of some kind to drain the oil out at a controlled speed so it was a balancing act between the oil coming from the temperature actuated valve and the venting through the orifice. I know after spending a good chunk of money rebuilding one we talked seriously about replacing the assembly with the next time with some electric fans that were just starting to be common for pickups towing trailers. Maybe three or for what ever we could fit in there and a simple temperature switch and relay. Never got the chance as trucks were shipped to another quarry before that happened!
The early 992 loaders with the D348 engines used the same set up, drove off the front gear train. I don't recall those being a lot of trouble.
Dmiller for the win . No wonder i cant find any info on that thing. That truck and another are slated to be sold. Thanks for the info my brain can rest now lol. Once he finds another large 3 wheel case spreader the trucks will go to auction or sold to a local farmer possibly , so hopefully i wont have to deal with a failure between now and then .
They used them in trackloaders also , my lead guy wanted me to help him do headgasket i said no rite quick and in a hurry.
Forget what the problem was with the one I worked on, just remember that compared to the simple air operated clutch fans on the Euclid haul trucks it seemed to be a lot of expensive parts, gears, seals, bearings and such. Probably like a lot of things the biggest cause of problems was lack of basic maintenance. We got the machines second or maybe third hand from other parts of the company so no way to know how abused they were when they got to us! And just for anyone interested in this fan drive RZucker mentioned:
mystery solved well done
Ken, The reason that you can't find anything in SIS about the Rockford fan clutch is that AFAIK they were Custom Shop attachments and as such were never published in anything other than the old blue-covered Custom Shop papar manuals. HOWEVER, there was one model where the Rockford was actually in the Parts Manual, the 994. At high altitude it was normal to specify a fan clutch so that over 100BHP could be recovered to run the machine systems, especially when ambient temps were cold so you hardly needed a fan. When the engine was so derated because of the altitude (around 12-15% was considered normal) every HP that you could get back was a bonus. Below is what a Rockford clutch looks like for a 994, although truth be told it's probably comparable in size as an assembly than the engine that the OP is working on .....!!
The one above looks similar to the one I saw IIRC, but this Detroit was just on a engine stand along with 40 other Detroits and at the time i really didn't pay that much attention to it other than it was odd.