Further brake issues...

[DCAlbarran]

So in another thread I sought help in finding a rear brake tube for my 63 FJ45 swb, which I was able to make happen. Now that I replaced the tube, I bench bled the master cylinder (didn't have to pump it very much. Got a rise in fluid level when I pumped, a fall when I let go, and no signs of air), re installed the master cynlinder (which is as upgraded dual circuit one) and then proceeded to bleed the brakes with help from a trusty sidekick.

During the bleeding process, it was very difficult to build enough pressure to bleed the brakes, having to pump the pedal 5-10 times each time to build enough pressure. I am fairly sure I have gotten all the air out, but depressing the pedal still gives me no pressure.

The brakes have been rebuilt at some point in the last 10 years or so, but saw little to no use as the truck sat. What am I missing here? I don't have any signs of leaking fluid, I can only imagine a bad master cylinder, but it still gives me good pressure when I have it off the truck and on the bench.

Thanks for your help. It's killing me not to have her on the road!

 

[DomSmith]

Assuming its original drum brakes I can’t imagine the cylinders operating as they should after sitting so long. And the boots would potentially be toast too.

Have you pulled all the wheels and drums at each corner and inspected them? Do they adjust each way? Careful not to put too much pressure on them depressing the brake pedal with the drum off... ask me how I know. Are they adjusted correctly? How much drag when you spin the wheel while it’s off the ground (rears are a little trickier to do).

It does sound like you’ve got a leak (you’d be seeing a drop in fluid) or air in the system. But being sure all 8 cylinders are operational will help cross that off the list.

 

[tornadoalleycruiser]

a rise and fall in fluid makes me want to believe you didn't get it bench bled correctly. Did you run a tube out of the master to each cup?

and secondly, do you have any idea the age of the drop hoses on the vehicle? they can swell inside causing a loss of pressure. IIRC on an older 45 there are 2 at the front and one at the back. One per front hub and one down to the rear diff in the back.
Since you have 4wheel drum brakes i cannot help you with adjusting them. I know they are very labor intensive and if / when they work they supposedly work well.

 

[DCAlbarran]

I have receipts from a bunch of brake parts, including hard lines and hoses, shoes, etc dated 2010. Truck has not been driven much of at all since then. Was also upgraded to dual circuit M/C at that time.

If I had a leak somewhere, wouldn't I find brake fluid somewhere? That's what's killing me.

 

[45Kevin]

It is very important that the shoes be adjusted correctly.
Have you done that?
With four drums, eight wheel cylinders, it takes a lot of extra pumps to make a poorly adjusted system operate.

 

[DCAlbarran]

It is very important that the shoes be adjusted correctly.
Have you done that?
With four drums, eight wheel cylinders, it takes a lot of extra pumps to make a poorly adjusted system operate

I assume that it was done properly based on who did the work, but it was back in 2010, and the truck has been sitting since then.

 

[45Kevin]

Adjusting them properly is not that hard. Lift the wheel off the ground and tighten the adjuster until the wheel wont turn and then back it off until it turns not quite freely. You should be able to hear a bit of a scaring sound.

On mine at least, it is very easy to back it off too far and thus need several pumps to fully place the shoes on the drum.

 

[DomSmith]

I’ve also found its good practice to go back and readjust again after just a few stop and go road miles once the shoes center themselves better in the drums.

 

[DomSmith]

If you know the brakes are adjusted properly then you can cross that off your list. You’d be surprised how much these brakes can get hung up after sitting for that long. I’d bet you have adjustment issues or sticking cylinders. But, if you open up and take a look and they’re working properly and adjusted then look for something like Tornado mentioned. A weak rubber brake line that balloons up will take up some of the fluid.

 

[DCAlbarran]

If you know the brakes are adjusted properly then you can cross that off your list. You’d be surprised how much these brakes can get hung up after sitting for that long. I’d bet you have adjustment issues or sticking cylinders. But, if you open up and take a look and they’re working properly and adjusted then look for something like Tornado mentioned. A weak rubber brake line that balloons up will take up some of the fluid.

Roger that. I’ll be off for a few days starting friday, I’m planning to get the truck up on stands and take a look.

 

[tornadoalleycruiser]

you will not notice the brake line externally, at least i hope not! in the late 90's after doing a brake swap on an older truck we could not get any brakes, confused as heck until we replaced the old drop hoses and flex hoses on the front axle. voila.. fixed.. I never want to do a test drive like that again.. I can see the 2 long front drop hoses in one of your pictures from when you had it delivered. I'm guessing it might still have the 9mm brake fittings, not sure if there are replacement hoses in the 9mm size. So perhaps everything was upgraded to 10mm fittings and is new from 2010, maybe not. Most newer brake hoses have a date code on them similar to tires if not an actual year of manuf printed on the hose. I understand wanting to keep everything stock and OEM but brakes in my opinion not so much.
Later trucks went to a single drop hose and a flex hose at the knuckle. it would require modifications and retrofitting newer stuff if you decided to go that direction. Good luck with the diagnostics.