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Case 780 Restore

James Madigan

Member
Joined
Sep 30, 2021
Messages
24
Location
Lake Ariel PA USA
I bought an old Case 780 2 months ago.Found out the radiator leaked and the brakes dont work.The compressor belt was missing and the mount was messed up.Got that figured out and done.The master cylinders were dry, machine sat for some time. Engi9ne is good. Refilled the master cylinders and see a drip on one wheel.Tried to bleed brakes and had to screw the bleeder all the way out to get drippage.The brake actuators at the masters are working with the air running but still no brakes. I cat pull wheel now I put some hydraulic fluid stop leak in the line thats dripping. Im going to try to adjust the brakes at the wheels.The emergency brakes not working either.Is there any way to tell if the linings are good?
 

Tinkerer

Senior Member
Joined
May 21, 2009
Messages
9,342
Location
The shore of the illinois river USA
The master cylinders may need overhauling.
The wheel cylinders prolly needs to be repaired or replaced.
You would need to remove the tires and the brake drums to inspect the linings.
Did shorten the parking brake adjuster to try and get it to actuate the brake ? It may have a control valve not functioning if it has one.
Stop leak in hydraulic fluid is a waste of money. The only way I know to fix a brake line thats leaking is replace it. Or if it is a steel line you could cut out the rotten section and splice in a new piece.
 

James Madigan

Member
Joined
Sep 30, 2021
Messages
24
Location
Lake Ariel PA USA
Ok, cant find shoes for this Case 780- Part# L33102 superseded by N9261 Did order wheel cylinder rebuild kits $75.00 each from Groff equipment here in PA I tried Broken tractor and 5 other case dealers . Does anyone have a source for the shoes? And Tinkerer i have the parts book and original service manual. Thanks
 

Tinkerer

Senior Member
Joined
May 21, 2009
Messages
9,342
Location
The shore of the illinois river USA
It is good you already have those books. They are invaluable. Especially the parts book. CNH has dropped a lot of the obsolete parts numbers from their stupid online parts book.
Start looking for a brake shop that will reline them.
I am quite sure any heavy truck repair shop can fix you up.
 

James Madigan

Member
Joined
Sep 30, 2021
Messages
24
Location
Lake Ariel PA USA
ok got the right rear wheel off. There is a 3 1/2" nut holding in the bearings. Didnt have that size so chiseled it around and off. I underdstand the torgue on that is very important so that you dont squeeze the bearings down. Anyone know the torque on that? Or the number of revolutions to tighten it. The brake linings have a lot of meat on them, one wheel cylinder leaks so i got rebuild kit for both wheel cylinders. One of the wheel cylinders leaked so i cleaned off the lining with oven cleaner and roughed them up with 100 grit paper. Im glad i dont have to get new shoes because the only place that had them is Southern Equipment and that was $320 apiece. Been dealing with Groff tractor here in PA for parts for the machine.
 

James Madigan

Member
Joined
Sep 30, 2021
Messages
24
Location
Lake Ariel PA USA
Hello Again, worked on both rear wheels,removed planeteries,put in new wheel cylinders and cleaned up the brake shoes, one side was wet with oil from a leaking axle seal, got a new one put it in. I am having a very hard time adjusting these .Anyone know how to turn the star wheels to expand the shoes? is there a trick to it. And i also vacuum bled them, but in book says pressure bleed them, is perssure bleeding necessary. The air brake actuators are working and air pressure is 120. Just cant get it to stop well.Thanks for any advice you can give Jim
 

Tinkerer

Senior Member
Joined
May 21, 2009
Messages
9,342
Location
The shore of the illinois river USA
I have never worked on a 780 with that style of adjuster. So, I can't give any advice there.
Hydraulic brake systems always need to be bled after opening them for service.
Pressure bleeding is a good way to do it, but I have done quite a few by depressing the pedals.
 

James Madigan

Member
Joined
Sep 30, 2021
Messages
24
Location
Lake Ariel PA USA
Ok looks like the master cylinders are at fault, no real fluid pressure when applying brakes.I am now looking for part numbers for the master cylinders ,or rebuild kits ,Case no longer has them. So i am trying for Bendix part numbers
 

James Madigan

Member
Joined
Sep 30, 2021
Messages
24
Location
Lake Ariel PA USA
Ok im waiting for parts, 2 master cyls and 2 diaphragms for air cans( they are for M48 army trucks) but i found lot of oil in the air canisters i knowit must be from compressor leakage I am wondering if i have enough air pressure to squeeze the master cylinders. Going to try mount a pressure gauge on each air line at the air canisters.
 
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