Thanks to all the guys who helped me out with the brakes on the Ram. It was a major PITA every step of the way and I ended up replacing the following:

Front rotors
Front hub/bearings
Front U-joints
Front calipers & pads
Rear drums
Rear shoes
Rear hardware
Upgrade to larger wheel cylinders (https://dodgeforum.com/m_498851/tm.htm )

But now my pedal is soft as hell. The brakes work, but it goes to the floor and they won't lock up (not that locking up is good, but it suggests that there is still some extrabraking power I'm not able to use). I've bled all four corners excessively, adjusted the rear shoes until they're just touching the drums and done every other trick I know for soft pedal. Strangely, it feels better in reverse than forward.

So here's my concern: did I screw up using those larger wheel cylinders that are described in the link above (went to Autozone and bought 1996 Chevy 1-ton wheel cylinders)? I'm concerned that the master cylinder doesn't have enough capacity to fill them. Instead of changing out wheel cylinders (PITA), is there a larger master cylinder that's a bolt in? If push comes to shove, I'll go back to stock wheel cylinders.

Advice? Thanks for all the help. I'll get this bastard back on the road even if it kills me.

 

If your pedal goes to the floor, then there is probably air in the system. Did you check all you lines? One of your brake lines might be leaking.

 

thats a lot of new parts. the only thing i see not replaced is master cylinder, brake booster, and front hoses.
the rear wheel cylinder should not be the issue, as its a common mod, generally with good results.
you didn't mention what started you to doing the work. is it now acting different, or still acting the same ?

air in the system causes soft and spongy pedal, although it will usually bleed out. if you have a fluid leak, obviously thats bad and can suck air in. old, rotten front hoses can swell under pressure and create a soft feel. master cylinder not holding pressure also creates soft and fading pedal. how old is your master cyl ? i'm not sure what symptom is caused by bad booster.

 

Matt, sorry to hear about your problem. Yeah major PITA when we have major work that really needs to be done on our daily ride. You will figure it out.

As for the master cylinder concern, if you go back to the link to a discussion on this forum about the wheel cylinder upgrade. Burning Rom, a very helpful moderator who seems to be on leave from this site for awhile, mentions this concern and said there was plenty of master cylinder pressure and volume available. If BR recommended it, I always found, it was a great recommend. I have a '97 2500 and never had a problem like you are describing since my upgrade. I'm very happy with what seems to me to be a definite improvement with my brakes.

I was going to say bleed, but you did. If you did what your list says, then you obviously know how to bleed brakes. My universal job turned into that same list and ball joints,tie rods and then to a shop for analignment. One day turned into the weekend and I was done by Tuesday but she was running smooth, well except for when it was raining or foggy, then it would runsmooth when the wires dried. So, wire time andwhile I was in there, I went for, Napa cap and rotor, and Champion plugs. Midlife truck is happy, for now. Shocks are on the short list.

So what's the problem? Can you or did you or do you need to, bleed the master cylinder?

 

Thanks for the responses. I did bleed the brakes very thoroughly using an assistant to pump up the pedal while I opened the valve: pump, pump, pump, hold, open valve, pedal down, close valve, repeat. I went through 3 pints of brake fluid during the process and use a clear hose so I can see the bubbles. I bled all four corners until they ran clean. I tapped on the calipers to dislodge any air bubbles, too. Not a chance of air in the system. Yeah, rubber lines can swell a little, but not this much and it wasn't an issue before all this work--pedal was good.

I did replace one of the hard lines on the driver's side rear axle--it was rusted and as soon as I tried to remove the fitting from the wheel cylinder, it snapped. New line, no problems, no leaks. Line from master cylinder to rear axle is new and dealer-installed, the rest are probably original. Already checked for leaks and found none. They're holding pressure no problem.

E-brake works well, with a high, firmpedal rather than sinking to the floor before grabbing as before. E-brake MUCH improved.

Master cylinder is likely original. Before this work, the brakes had a nice, firm, high pedal--I only started this whole stupid mess because the front rotors were warped and I wanted to change them. Everything else worked just fine. I only replaced the calipers because the bleed screw nipples broke off when I tried to crack them open and I failed in my attempts to drill/EZ-out/torch them out.

NOTE: I have a good, high, hard pedal when the engine is off. Booster problem? All of a sudden like this?

The calipers are the correct replacements--the decal on the driver's door says it's an 8800 GVW truck, and the front axle is a 1-ton (which I discovered because I needed the larger 1-3/8" U-joints). I was concerned that they were too big, but I just double-checked and they are correct.

The only variable is the wheel cylinders. I went to AutoZone and asked for wheel cylinders for 1996 Chevy 1-ton dually, as the link suggests. That's the only non-stock piece, the only real question mark on the whole project.

And an ABS question. I assume it has RWABS, but I've never experienced it in action, even in winter,and assumed it was non-functional. However, when I was testing the system on the road today and doing hard stops, as the pedal reached the floor and the truck was braking hard, I could feel what seemed like ABS pulsing through the pedal. But I'm not entirely sure--it also felt like maybe the MC was bottoming out or something. Weird.

Thanks guys. You've been a big help. Let's see if we can finally get this bastard finished.

 

Maybe borrow a vacuum bleeder from a loan a tool parts store and bleed them with that. Obviously if you are 100% cofident that all the air is out like it seems you are then you won't, but It seems like you did everything right and air is the PITA here. Are you certain the front brakes are working? When you say it seems better in reverse it makes me think the problem is in the front. Once I had a jeep I did brake work on and then proportioning valve wouldn't work properly and it acted similar. I got a new one from the wrecking yard and it fixed it.

 

How far down did the brake pedal go down during bleeding? I usually put a block of wood behind the pedal so it can't go to the floor. If the pedalgoes past it's usual range of travel there's a risk of damaging the o-rings in the master cylinder. Anyway just a thought.

 

Usually you have to bench bleed the mc, then the combo valve, then any antilock manifolds.

I would guess you have air in the lines.

I didn't read all the posts. Do you have vacuum brakes or hydroboost?

 

I'll give it another try with the bleeding just to be sure. I have a vacuum pump that I'll use. I don't typically like to use it because it can sometimes cause air bubbles by boiling the fluid as a function of zero air pressure. But it certainly can't hurt to try to pull more fluid through the system. The ABS manifold and MC shouldn't need extra bleeding because they were never open--just the wheel cylinders and calipers, which wouldn't have let air get that far up the system.

I'm fairly certain all 4 brakes are working. They're all hot after a test drive, and like I said, the truck stops hard and is probably safe to drive as-is, it just has a mushy pedal that it didn't have before. It really does feel like the MC is too small, though it seems that shouldn't be the case.

I figured it worked better in reverse because the rear brakes were adjusting themselves. The first forward stop after an aggressive backward stop was pretty firm, then it went mushy again. I have vacuum boost, not hydro boost, which might be only for diesels?

My partner probably pressed the pedal to the floor--I never used a block of wood before, but that's a good idea. How to tell ifthe MC was damaged? I hate to just keep throwing parts at it.

Amazing that they actually invented drum brakes before discs--I'd like to kill the guy who invented these Rube-Goldberg contraptions. Thanks as always!

 

I still think there is air in the system some where. When you said you had better brakes in reverse because they were adjusting, I don't believe they are adjusting that much to give you brakes in reverse and then "unadjust" in forward.

Are you sure your rearshoes are adjusted to the rear drums? Use a brake spoon to adjust them so they are definately touching, not just skipping ocassionally. If you have too much travel in the shoes that would cause the pedal to mush down.