I have a 1986 F700 dump truck, single axle 370 gas engine 5 speed transmission, hyd brakes. After doing a days work hauling gravel, parked the truck, raised the bed and quit for the day. Next morning truck engine would not turn over, could not move engine by putting a bar on the starter ring, could not move the truck with the Bobcat, wheels lacked up with either the transmission in neutral or with clutch pushed in, I am baffled, need some ideas, got to get working as the Summers are short here in Alaska, any help or ideas appreciated, Patrick

 

You need the engine running to release the brakes. I can't do a decent search and post links so try a search for Lucas girling brakes and how to release them. You will see pretty quickly if you have those brakes . As to a locked up engine could be a major failure or a jammed timing chain. Stand by for more

 

Thanks for the help, will be looking at timing chain, gonna be trouble moving truck with brakes locked up.

 

The rear brakes have a spring parking brake on each wheel. There is a threaded rod sticking out of the middle of them. I believe they have a 3/4 nut on them and the brakes are released by tightening them intel they bottom. I once did a delivery and could not leave because the brakes were locked up. The belt tensioner or some such broke and would not turn the pump. It was a long walk, before cell phones and I had no tools. I turned the pump pulley by hand and released the parking brake. Don't remember if I had to use a stick holding the button in or anything. Yes it took a while.

 

Pull the spark plugs out and try to crank it over, we had a 83 F-700 with 370 engine, every time it rained water leaked around the hood seal onto the air cleaner which is dished in, the water would then leak into the engine around the air cleaner stud and fill one of the back cylinders hydro locking the engine.
Have you tried turning the engine ether direction.

 

Thanks for the reply, here is an update, timing chain is good, haven't tried pulling the plugs but cannot move engine with a bar on starter ring in either direction, dropped pan and don't see any damage, altho there was a small amount of water, just water no antifreeze, so guess we'll try something else in the morning. Does anyone know what engines will swap into this mess if I have go that way, I think a 429 out of the same series truck will work but don't know about any others. Patrick

 

Pull the plugs out before you check anything else.
370 and 429 are the only direct bolt in's.

 

Found the problem, N0 7 piston and crankshaft counterweights are jammed together resulting in bent con rod and other yet to be found problems, am working on getting engine out and disassembled, sounds like I will be seeking a replacement engine. Any body have any suggestions as where to get an engine ? (in Alaska if possible)All for now, Patrick

 

Still looking for an engine, need a 370 or 429, will a later vintage engine than the carbureted engines work by just changing the intake manifold?

 

Pickup efi motors have different heads than carb motors. An adaptor is needed to mount a carb. Distributor might be an issue. If your heads are good you could swap them over. Not sure when the medium went efi or how.

 

If the cylinder is good just get another rod and piston and put it back together.

 

Don't know what the damage is yet, if it's not too extensive I'll just get what I need and put it back together, was just wondering what would be a good replacement engine. Thanks, Patrick

 

Because of mounting and accessory drives, you are limited to the 370 for a direct, a 429 for a direct with a little fussing fit. Car or pickup 460s will be some work, can be done. If you want I can dig that thread up, but not today.

Of course you could really get the old checkbook out and put a diesel in there.

 

I've got a 1990 Cummins 12 valve sitting here in the shop, just didn't want to start another project.

 

That's a no brainer. Swap in the Cummins.
My 93 F-800 is factory 8.3 Cummins
My 04 F-450 is 5.9 Cummins
Maybe I'm a little biased plus I don't care for 370's, always felt like a good 330 would out pull a 370