2nd Gen Non-Engine/Transmission Brake problems

[raxley]

I've replaced the brakes in my truck 4 or 5 times over the years, but I have a problem I haven't run into before. I have hardly any 'pedal', and if the pedal is being pushed down, eventually the pedal will go all the way to the floor. I just replaced the master cylinder, it didn't change anything. I have terrible braking right now. I just replaced the front brakes, but I can't even get the brakes to lock up. Can this be the boost thingy?
I took the back drums off, and my couple of year old rear brake job seems to be doing ok, but it feels if I only have about 50% of braking that I should have. The rear brakes are being used, I can tell by the fresh exposed metal by the brake shoes, but it doesn't seem to be making a difference to stopping.
Another related problem is that I've never had a emergency brake. Everything is there, but I cannot take enough slack out of the cable system to actually have the brake shoes touch the drums when the emergency brake is pushed down.
I took a picture of the cable adjust arrangement. In the top picture, you can see that I've taken up all of the slack that I'm able to with the set up. Is this the correct brake cable? It has one cable going from the emergency brake pedal to where the adjustment arrangement is, then it splits into 2 cables, each going to their respective drums. The top picture shows where the cable is bent around the hardware to "fasten" it. It's the bottom cable in the top picture. Surely this is not the stock arrangement?
The lower picture shows where there is no "sleeve" around the top cable where it goes through the hole in the bracket at right. It is more visible than it is in the top picture.
Can the brake shoes in the back drums be too far away to produce good stopping power? And how do I get them closer to the drums?
Any help greatly appreciated!

 

[GAmes]

That's what my park brake assy looks like. Have you opened the manual and followed it's procedure? Are you sure the cables to each side are moving inside their housings? I had one freeze so the park brake didn't work much at all. Once the cables are adjusted the procedure is to adjusts the brakes manually. You shouldn't have to touch the cable adjustment. The auto adjusters just don't work very well. I do mine every other oil change. Adjusting the rear brake shoes might also give you your pedal back.

 

[Ozymandias]

Yes the brake shoes can very likely be to far from the drum.

 

[Bromiley99]

What year is this truck? Is the truck 2 or 4 wheel anti lock?
I’m currently experiencing this exact problem on a 96 I picked up a year ago, all I did was change the front pads now my pedal just goes to the floor. I also changed my master which didn’t help at all.
The only thing I can think of is the dump valve inside the abs block is stuck open. I’m planning on bypassing it just to see if it changes anything just haven’t had time.

 

[Ozymandias]

What year is this truck? Is the truck 2 or 4 wheel anti lock?
I’m currently experiencing this exact problem on a 96 I picked up a year ago, all I did was change the front pads now my pedal just goes to the floor. I also changed my master which didn’t help at all.
The only thing I can think of is the dump valve inside the abs block is stuck open. I’m planning on bypassing it just to see if it changes anything just haven’t had time.

The dump valve can fairly easy be checked from the outside.
Check YouTube for how to do that on the Kelsey-Haynes ABS unit.

 

[Bromiley99]

Ozy I was never able to find a way to check my dump valve but I did spend a little time yesterday made this brake line up to bypass my abs block. However it did not fix my problem.

 

[Ozymandias]

You should have these two rubber grommets.

Take them off, put a needle or something into the hole(s) and have someone push the brake pedal - if the needle moves outward your unit is leaking. If it does not move your good.

 

[surfbeetle]

When I replaced the master cylinder on my '95, even though I bench bled it before install, I ended up having to use a power bleeder before I had a decent pedal. Also, on the rear drums, adjust the shoes all the way tight and then back off a few clicks, they'll need to settle into the correct position on the drum. The parking brake should make no difference to your pedal assuming the shoes are properly adjusted.

 

[Matt42]

For what it's worth, I think you may have a couple of things going on, maybe a few more. I am stealing liberally from prior posts. But I have a few initial questions.

• What condition are your calipers in? New? Rebuilt? A lot of rebuilt parts tend to be junk, even with a lifetime guarantee. When I finally get around to replacing the calipers on my 1996, I will have them rebuilt by White Post Restorations on the east coast. They will insert a brass or stainless steel sleeve.
• Is your new master cylinder new or rebuilt? Same comment as above.
  
• Your E-Brake adjustment assembly looks just like mine, but yours has been cranked down more. If the rear brakes are in good adjustment, little to no E-Brake adjusting is needed.

My thinking on the problems:

• If you don't already have one, get a copy of the factory TSM.
• I think your rear drum brakes may be out of adjustment. The shoes can just "kiss" the drum surface enough to make it look like there's some engagement going on. But there really isn't enough.
  
• Lift the truck so both rear wheels are off the ground. Get a manual brake adjusting tool and hand-adjust each brake with the wheels ON. You should just barely feel a tiny bit of drag with each revolution of the wheel. (Be sure that your E-Brake adjustment is fully backed off before you do this.)
• After your initial manual adjustment, find an empty parking lot and back your truck up, sharply applying the brakes several times during each back-up. It goes without saying, but I will say it anyway, be certain that the brake hardware for each brake is on the correct side! If it's reversed, bad things can happen!
• Readjust your E-Brake only after you have done the manual adjust and the repeated backing-up.
• If you have not already done so, replace the rear wheel cylinders with those from a Chevy/GMC 1-1/2 ton truck. (The brakes are a Delco system, anyway.) This was discussed in detail some 20 years ago on the TDR as a way to improve braking. I made the retrofit on my 1996 and it works great. It's so good that I quit thinking about a rear disc swap.
• There may still be some air in your system. Even one tiny bubble can produce a mushy brake pedal, and a little more can give you no brake at all. By 1978, I had given up on manual bleeding and started using a pressure bleeder. (The bleeder was made for late model GM La Salle cars, BTW.) It worked far better and my wife was grateful. Bad news: The new style cover-the-reservoir bleed adapters are junk. They don't hold pressure and they pour brake fluid all over your truck. You need to find the older style that have rubber-capped tubes that nestle down into each front/rear input port inside the brake fluid reservoir.
• Do you have a brake fluid leak? I think that is not likely based on the clean pictures you posted.
  
• Has the vacuum line come disconnected from the booster? That would normally cause a hard pedal, though.

 

[Matt42]

A little more. I was shocked to discover that someone is now making a decent brake bleed adapter that'll work well on 1994-1997 Dodge Rams and Delco brake master cylinders. It ain't cheap, but nothing is.
https://speedibleed.com/product/c200-gm-brake-bleeder-adapter/