Well, if it were me, I would put it on jackstands and the transmission in neutral; I would then spin the rear wheels and see if I can hear any dragging of the shoes on the drums; if I couldn't, I'd then hope for the best and try to remove the drums without adjusting anything (I try to not CHANGE something if I'm just trying to look) but of course a ridge on the outer edge of the drum could prevent that. Regardless, that is how I would begin, and I'd back off the shoes only of necessary.

 

Backing off the shoes all the way before bleeding actually helps ensure all the air is out of the lines because you're having to move more fluid to get the shoes in contact with the drums.
This is the factory recommendation on Land Rover drum brakes which are the same design, less the parking brake mechanism.

Of course you have to remember to adjust them properly once you're done bleeding and also keep in mind you'll have excessive pedal travel until you do.

 

For the price of the drums, shoes, and hardware kit as well as adjusters, and wheel cylinders for that matter, I would start from scratch on the rears....that way, you know exactly what you have with no guessing. I would see it as a sound, braking investment.

 

Just an update. It definitely was the fronts.

Just a little background. I bought this truck at the end of 2014 (I think) and have barely even drove it. Honestly, the only time I did drive it was to go get some new tires put on it. Other than that, it's pretty much sat in my carport until I had some time to actually get to work on it. Before I had the truck, it sat for years at the PO's. I doubt the fronts have worked in a long time.

My guess is that I had 2 separate problems. The front calipers were froze in the open position, and I wasn't bleeding the fronts properly. It's not that the rears were locking up... I just didn't have any front brakes at all. I could brake with them, I just had to be careful to not slam them which would cause them to lock up at that point since there's no weight in the back. I'll still remove the drums and check the shoes, etc.. I do not think there's any oil or fluid on the pads though.

I was able to finally free the front calipers but they are still freezing up like I'm pressing on the brakes. So now ironically I've got front brakes but too much. Sometimes it'll free up, but it's random. I've not pulled the calipers off yet due to weather, but will be doing that. I'd say the slides are probably rusted up from sitting for so many years.

 

Sounds like you've got a handle on it now. Thanks for the update.

As far as the old calipers and hardware, don't even mess with them. New (or rebuilt) ones are inexpensive. Good insurance.

What exactly was the problem with bleeding the fronts?

 

The front calipers freezing up is a common problem, especially with vehicles that sit around and then new pads are installed. Rust develops behind the pistons and then when you take a c-clamp and push the pistons inward for the new thicker pads, the pistons go over the rust and get sticky.

A sign that the slides are locking up is one pad is thinner than the other. Cleaning and lubricating the slides is an important part of brake work on the front.

 

The problem was that since I was using a vacuum bleeder and the front metering valve on the proportioning/combination valve is normally closed due to a spring that holds it closed until the brakes are pressed and the pressure overcomes the spring (somewhat like a check valve), the vacuum bleeder was not giving enough vacuum to cause the metering valve to open. It would let a tiny bit of fluid past it, but apparently it was holding the air in before it in the line from the master cylinder.

So, If you have one of these valves, like others have said, you really cannot do a one man operation with a vacuum bleeder (there is one way.. keep reading). You can do a one man bleed operation if you install bleeders that have a check in them to prevent the air from coming back in the line, but you'll have to press the pedal to get enough pressure to overcome the front metering valve spring. In the case of my truck (1982 F100 5.0), I might have been able to hold the bleeder rod out on the proportioning valve which is actually the front metering valve shaft. Then I probably could have used a vacuum bleeder.

 

Honestly, I've not even changed the pads, or removed/checked the calipers. From what I can tell, the calipers are probably original so I'm already in the process of sorting some new pads, calipers, shoes, drum brake rebuild kit, and drums...

And as far as 'an important part of brake work'.. Anything would be better, especially since I've not really done anything to the brakes on this truck other than replace the master cylinder... and that was 3 separate ones. I bought this truck just to work on. I've got a couple other newer vehicles we use for daily drivers, so that's why it's sat for quite a while..

 

About this one-man vacuum-bleeder thing; I have one and wasn't real happy with it for some reason but cme up with something that uses that device and seems to work fairly well....

The thing I have is just a capped, plastic cup with two inlets for hoses on the cap; one of the inlets has a tube that extends to the bottom, I pour a bit of clean fluid into the bottom, just enough to reach the hose in it. Attach one of the long hoses to the inlet with the tube going to the bottom.

Attach the hose to the bleeder, crack it open a bit (half a turn or so? don't remember).

Set the cup on the ground, now go pump the pedal until the cup is almost full; close bleeder, disconnect cup, empty it most of the way (but leave a small bit in the bottom), reattach and re-open the bleeder, add fluid to the master cylinder, then repeat the entire process. I can't see the air coming out so I'm not really sure when to stop, but I always continue on for at least 2-3 cupfuls once there is clear fluid coming out.

Some people are probably going to say air will leak in past the threads when the pedal comes back up; I kinda doubt that (fluid never comes out from those threads during a normal 2-person process) but I guess one can squirt some brake fluid onto the bleeder threads to seal any such potential leaks if that concerns you.

This seems to work pretty well and totally flushes the system (I use at least half a gallon of new fluid when I do it this way).

 

Lots of interesting reading to digest in this thread. So did your last bleed extinguish the light? If so, that means the pressure is the same in both systems and you are making lots of progress.

 

I have had the threads leak when using the vacuum method on the bleeder. That's were all the little bubbles come from when you keep pulling a vacuum on it. Other people have had this problem also, and is why the "mity-vac" type of bleeding is losing favor.

I guess you could put some thread tape on the threads.

 

That's to the 'T' exactly what was happening to me. Where the front metering valve in the proportional/combination valve is being held closed by a spring like a check valve, the vacuum even at 13-15psi was not causing that valve to open so It was forcing air in through the threads and back out the bleeder. Exactly like you said. Tiny little bubbles.

I still do not have all the air out of the fronts yet, at least I'm guessing that since my light is still on. I pretty much just parked the truck for now until I get a chance to pull the calipers to do some inspecting/replacing.


So for those that have a mushy brake pedal and/or the brake warning light, don't even try to bleed the brakes with a vacuum bleeder. I did try to do it with the bleeder rod held out on the proportioning/combination valve, but I was still only getting a little fluid and seemed like there was a restriction. It's better if you just go ahead and get a helper to push on the pedal and do it the old fashioned way.

BTW.. Just another tidbit... If you are just bleeding the rears, you won't have as much of a problem and can probably use a vacuum bleeder. It will still be faster using a helper pushing on the pedal since the proportioning valve for the rear will slow down the flow of liquid so you'll still have to overcome that.

I guess the best form of learning is experience. And I'm racking up some serious experience now with this dang-fangled proportioning/combination valve. I'm still tempted to run straight to the fronts and put an adjustable proportioning valve only on the fronts.

And in case you're wondering... Yes... I did sleep with a proportioning valve at a Holiday Inn Express... We'll be expecting baby valves soon. If she doesn't start acting right though I'm dumping her...

 

Before getting too crazy and "fixing" something that may not even be broken, I'd concentrate on the known issues, namely the frozen front calipers. Could be once you get that fixed, followed by a proper bleeding, you may find everything else is groovy, including the proportioning valve.

If, on the other hand, you enjoy doing more work than you need to, can we at least redirect that energy? My house needs to be painted. Thanks

 

You mean run straight to the fronts(as original) and install the proportioning valve to the rear correct? That's they way you should do it.

If you want to have your cake and eat it too, you could put the adjustment up in the floorboard of the cab somewhere easy to get to. Play around with it and then make a mark on the **** for loaded braking and unloaded braking. You can put more power to the rear with a load in the bed. That's ultimately all the factory was trying to do with all their RABS systems and valves mounted to the axle housing back there on the later trucks.

 

I don't think what I said was 'getting too crazy'. What I'm talking about is actually a common setup. Everything you mentioned is exactly what I said I was doing.. hmm..