Well I'm prepared for the worst on this one..bought a f700 dump not running but you know "ran when parked but smoked bad so needs overhaul"..the truck is complete..manual with the 370 gas..so a towing/junker lot had it listed and I took it at less than $2000..thing is it was hauled to my farm on a row back..very large rowback..so about the rear brakes..story from the hauler is that the rear brakes are applied/engaged due to the compressor so the truck was slid off the rowback after oil was poured out in the tire pathways of course. I guess I'm wondering if the rear is just locked up and they knew it or is there other reasons the rear wheels didnt move..Not experienced at all in medium trucks and would appreciate hearing the suggestions and experiences..going into this I kept the attitude that it's a parts truck that maybe I could get running at my farm only..thanks
Spring lock brake cans more than likely and with out air pressure you can’t release them unless you cage them but with doing that you lose your parking brake
Easiest way is to remove the drain valve from the wet tank and install an air hose in there, then just air it up from an external source and you can chock the wheels, then check and see what works.
86 F700 with 370 lima engine. I'm guessing you probably have the dreaded Lucas-Girling hydraulic brakes. If you have 2 large brake chambers pointed inward with 3/16 brake lines jumping from one wheel cylinder to the other on each rear then that's what you have. The park brake side is simple enough. There is a 3/4 nut stakes to a threaded rod in the center of each canister. Chock the wheels and back those threaded rod until you feel a firm stop. See if it rolls. Please see attached pics.
Gotta love an old Ford. How bout some pictures of this beauty?
Yep..that's what I have back there...and just caught a youtube video of caging them...thanks
Man..dodged one there..I guess I should be glad I don't have those lol
Guys will get some photos up soon..she's pretty rough but solid in the right places..
I am not being a *** but Try and take it back to were you got it even if you have to a loss.
If you aren't familiar with air brakes read up on them real good before attempting to work on them. The parking brake is under extreme spring pressure and loosening the wrong bolt can get you seriously injured if not worse. Be careful!!
Really?..if it starts, unlocks the brakes and dumps the bed ..all for the $1600 it cost me...sounds like good advice to me
I thought it had the lucas Girling brakes.
Ah..I see..must be some the worst brakes ever and expensive to fix..to be honest the standard hydraulic power brakes I have read about would've been idea.. Do types of braking systems have anything to do with tons/lbs the truck can safely haul? ...or does that(tons) depend on what the bed hydraulics can dump?
He is likely to have never seen the Hydraulic actuator LGs on the Fords. If has a compressor will be Air Maxi cans.
They were basically wedge brakes, but hydraulic. S cams replaced wedges, and now air disc(boondoggle big step backwards) Lucas was a ****-poor attempt to make heavier trucks (up to 30k) sneak in under CDL requirements. They were legal, up to 26k because they were hydraulic not air. They never should have been. Glad you got air, kind of a unicorn. 370 glasser with air brakes. You gonna post those pics?
Yes..here's a few as it came loaded on the hauler..will get more up later as I get to looking it over more...
Need a photo under the hood, master cylinder will be Juice Brakes and Lucas Hydraulic Maxis under it.
We had one with full air, it had the big BW diamond brake pedal and colored Synflex hoses everywhere. The front brake cans were the tiniest I have ever seen, whatever size they were.
I think with those Dayton's, the only juice brake would be L-G or Wagner A2LS. And after blowing up the pic from the front, I can see S-cam brackets.
Looks good so far... Keep 'em comin'!
IIRC they may have used a type 8 or 12 front diaphragms and type 24 chambers on the rears of these with air brakes.
On your third picture there's a round object that looks like a vegetable can hanging under the right side of the front axle. Do you know what that is? I don't recognize it.
Yeah..its something emissions i think that has dropped down from its mount dangling down with vac hoses..will try to get more pics up soon ..maybe this weekend
Now that you mention that and it being a gas truck I wonder if it's a charcoal vapor canister as found on cars from that era? That would make sense.
I believe that is correct..not familiar with the ford gas engines of that era but sounds about right.
Ford's Tomato Soup cans!! Can remember culling those rusted leaking messes out of a old pickup or truck systems!! That and the Air Injection stuff as the air pumps locked up or tubes rotted away.
Snapped a few more pics last night..
And more..some with mud dauber dwellings..
The rest of engine bay.. ..was surprised to not see a master cylinder or valve bank..hope nothing's rigged!
No master cylinder for air brakes. You will have a foot valve either under the floor or up under the dash. Looking at those air lines going into the firewall, I'm betting on under the dash. Just look at what your brake pedal moves.
That style of brake is pretty easy to service and very reliable. The rear cans are the dangerous ones, the second can is spring loaded to set the rear brakes for parking. That spring is under a great load. If you ever find you need to change a diaphram you have to be very careful. Make sure you chock the wheels as you'll be releasing the parking brake in the process. On the trucks I've worked on there's a "key" on the side of the air chambers, a threaded rod with a T on the end. You insert it in the hole you see in the chamber and twist it until it locks in to the park brake mechanism. Tighten the nut on the threaded rod until you can't tighten anymore and then and only then can you release the band clamp on the chamber to expose the diaphram. It would be best to have someone who has done it safely before show you the procedure, do something out of sequence and you could get seriously hurt.
Infamous 370 2V Two Barrel even more gutless than my 366 LP GMC They both do tend to be Energizer bunnies running on and on and on!!!
Gutless as in weak?..haha..hope it fires at least..i gotta go back and take a good look at the distributor..one of plug wires dont seem right..also looks like my frame is cracked in the pumpkin pic..darnit!
I think that crack is a ty-wrap.
Your right..i see it now..as it crosses the hole opening..that one was starting to turn my stomach..I have it parked just off the gravel drive a bit and lately haven't been able to really crawl around under there because of wet ground which makes slick clay mud..so just kinda pointed the phone under there and hoped for best picture.
Not so much Weak as in SLOOOWWWWW!! Enganears gave them gears and use them all, all the time for these Applications!!!
if you can't get the caging bolt in properly, and the keyhole inside is cocked off to the side, it indicates the dangerous spring is broke and requires a different removal approach to remove the brake pot
Haven't thought about a chance of broke up springs in the cans..I will tend to them most certainly if at start up they dont release the spring brakes..if i do get the truck running soon I'm clueless as to what to expect the brakes to do..have watched a few YouTube videos concerning some pressure checks and test but will probably seek help from some friends with experience with them..just that the largest truck I've owned was a Ram 3/4 ton..nothing with air brakes however.
Safest way on those is to just replace the whole can especially if you’ve never worked on them before
On the ones that either externally or cross leaks bad enough a engine compressor would not keep up would vise grip the operating rod extended then connect shop air set to 110# off a regulator to the spring can side, impact the clamping bolt on service side then knock the clamp away and release the air. On dump trucks where the cans got aggregate eroded would lay under the differential, would gas axe steel or sledge the aluminum cans until spring was free Generally had a loader bucket in the way to catch the parts. NOT a fun day.
Dad said in the woods back in the day old jalopy water truck was dead and blocking the road, they taped an impact wrench to the band strap nut and turned on the air from a distance, spring shot as high as the pine trees he said.
Have seen a few launch pretty hard!
I once caged the spring and then took the spring chamber off. I clamped the chamber in the vise, then reached out with a torch and cut the caging bolt. I wanted to measure and see how far the piston would fly, but I got disappointed. I didn't get to see how far it would go, because it hit the only tree in the area, and stuck into a white oak, about 40' up and 75' away! If it had the power to stab into an oak tree that far away, imagine what it would do to your skull at arms length!