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Discussion Starter · #1 ·
I’m still shaking down the 77 PW W150 I picked up before the holidays.  I’m on to the brake system now. PO said he just paid some shop to ‘fix’ the brakes because they were really bad. Well, they still aren’t right. My recollection of Dodge truck brakes comes from mid-80’s RC’s and 4x4 pickups. They all had a very high pedal and relatively hard, short throw.

This truck is power disc/drum. New parts here and there in the system, MC, calipers, hoses, sections of hard line. Anyway, the pedal is super soft and really long travel. I can jump on the brakes and nothing will even think of locking up.

Questions:
- Is this normal ‘feel’ for a 77?
- It looks like there are manual and power 4 bolt MCs that look identical. Brakes remind me of too small of a bore like you would use with manual brakes. Do the symptoms sound like a MC issue?  I don’t think the booster would cause this, do you?
- I did re-bleed the brakes and I don’t think that’s the issue, with engine off the pedal gets very hard.

TIA - I have a lot to look at yet but wanted to set my expectations on what brake feel and performance should be.
 

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I did not think manual brakes were even an option for the 4x4's. Even then, it would be hard to use a manual master on a power booster. The push rod is different.

From the 70's to the 80's, brakes should feel about the same. For the most part, the parts changed very little.

2 things come to mind. If the calipers are mounted on the wrong side, the bleeder will be at the bottom, instead of the top. Or, if the rear brakes are way out of adjustment, either can give the symptoms you describe.
 

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I dealt with the same issue on my 77 Ramcharger after swapping in a pair of D60s. New everything, MC, vacuum booster, calipers, bleeder screws, pads, proportioning valve, brake lines. Bled about a dozen times. Still had a low soft pedal. Also, I did a disk brake conversion on the rear D60 prior to the axle swap. I'm not sure if that caused the brake issue.
Granted, the brake pedal was soft and low before the axle swap. I just expected it to be firm with a short stroke after all brake components were replaced.
Oddly enough, over time, the brake pedal has gotten stiffer and doesn't go nearly to the floor now. No rhyme or reason why. I haven't worked on the brakes since just after the swap. It just became better over time.
 

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brake system should NOT be low /soft pedal with power assist operating . many things can cause that . poor fitment of shoes TO drums ,(improper adjustment will cause "low" pedal )  brake calipers , bad brake hoses , AIR in lines , failed brake combination valve .  you want to see a hearty squirt from BOTH front and rear bleeders , if one is healthy , the end other a tinkle , adjust / bleed the best you can , then with motor running , step HARD on the pedal that is suppose to recenter the combo valve ... and you may/should get equal velocity squirt front and rear . if not that valve is where the problem begins ... so 1st you need to go over all the brakes ... wheel by wheel .
 

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On my 83 4x4.  I replaced everything except the proportioning valve, front discs rear drums, calipers, lines, master, booster, etc.  Still had "bad" brake.  I then replaced the proportioning valve block on frame.  That made all the difference in the world.  Biggest and hardest thing is to get absolutely every bit of air out.  That can make or break stopping efficiency.  This valve balances the amount of load to the rear since drums and discs require different amounts of pressure. 

Neil
 

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I think all the previous posts all have 1 thing in common which I'm going to add to. Air in the system is your enemy. I struggled when I replaced the brake system on my 1980 Corvette which is notorious for getting bled. I used a power bleeder, gravity bleeding and good old fashioned manual pedal bleeding and nothing worked until I removed the Master Cylinder and re-bench bled it. Turned out to be air trapped in the bore.
 

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Discussion Starter · #7 ·
Thanks everyone. I know I have work to do for sure.  I think my expectation is set now. It sure does remind me of air but I’ll report back what I find. I’ll probably start pulling stuff apart this weekend.

The balance or prop valve is interesting. I got the dash back together last night after fixing a bunch of wiring. I noticed the brake light was on, dash light. That can only be from the e-brake or the brake valve. I’m fairly sure the e-brake wasn’t turning it on.
 

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Could you have a bad brake booster?  I know you are supposed to step on the brake pedal twice and hold it and it shouldn't go to the floor.  While holding the brake pedal down, turn the truck on and the pedal should slowly move toward the floor.  After that, you should be able to let the pedal up and pushed down and the pedal should stop, feel firm and never bleed down.  I've heard if it does the above the booster is fine.  Somebody might now more though.
 

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Discussion Starter · #9 ·
Booster seems fine. I did what your talking about. If you rest your foot on the brake pedal while starting the truck it should fall a bit as soon as it gets vacuum.

I did pull the MC tonight and pulled it apart. Everything looks clean. Bore size is 1.030” which seems small for power disc drum but the FSM says that’s what it is. Only other MC is a 2 bolt and that’s 1.125” which is closer to what I would expect. Not sure where I saw a 4 bolt MC for manual brakes.

I’m going to pull the brake valve and give that a good cleaning, blow out all the lines and see what I get after that.
 

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You have air somewhere or something relieving fluid pressure.

1. Due to recent repairs. Have you checked the caliper bleeder position? The only difference between the left and right caliper is where the bleeder is positioned. Just because one is correct doesn't mean the other one is. I have seen parts places mix them up in boxes. Check and make sure each bleeder is in the top side of the caliper. After that I would bleed it. I moonlighted at AutoZone to help pay for my kids classes. I had a man tell me the calipers were crap. He wanted to buy two more and would return the others once he got them off his truck.  I asked if his truck was in the lot. After inspection of his calipers I told them they were on the wrong sides. He insisted that I didn't know what I was talking about. Finally he says why are they not marked? I said they are with the bleeder.  I told him it was physics and common sense. He didn't like that. He left to switch them. He never returned. (More likely than swelling lines and simple to check)

2. Inspect the rubber lines.  They can get tired and swell. Have someone pump the brakes while you hold the line. I prefer to wrap a ziptie tightly around the outside and then have someone pump the brakes. It makes it easier to differentiate between the line moving and actual swell. (Least likely easier to inspect than bleeding)

3. Inspect for new lines. I can't honestly tell you how many bad flares I have fixed from other shops. It may only weep a slight amount of fluid but suck air. If it has a new line it's worth inspecting each end. (No probability if there isn't new lines installed)

4. Bleed your system. Start at the master cylinder. Have some one pump the brakes up and hold them. Crack each line coming off the master cylinder. It will weep fluid out. Do this several times. Then move to the right rear or passenger rear. Then the driver rear. Then the passenger front then the driver front. (Likely the problem)
 

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Have you ever "bench bleed" the master cylinder?
Do you know how to do that?
You said you took it off and inspected it.
One of the problems I had in the past was not "bench bleeding " the m/c.
It was full of air. When I performed the bleeding, I could see bubbles of air returning into the fluid wells.
 

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if you think about HOW the system works , logic dictates that miss-adjusted or poor fitting shoes and pads cause a "low" pedal . because liquid WILL NOT compress , and AIR will compress , air causes a soft pedal . Now in service what happens is a blending of both symptoms . if you had good brakes , and changed out 1 hydraulic part , allowing air INTO system , you'd KNOW it was an air problem , if you had good brakes and changed just shoes ,not opened the hydraulic system ,  and had a low/seems soft pedal , you'd  know it was a fitment / adjustment problem. Because every thing has been changed /touched/opened , and YOU never had good brakes with it , start from the beginning . work your way thru it and have the confidence knowing you have safe brakes when its done .
hell even stuff like real loose front wheel bearing can cause those symptoms ... to some degree .. it is what it is . 
 

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Discussion Starter · #13 ·
Mechanized said:
You have air somewhere or something relieving fluid pressure.

1. Due to recent repairs. Have you checked the caliper bleeder position? The only difference between the left and right caliper is where the bleeder is positioned. Just because one is correct doesn't mean the other one is. I have seen parts places mix them up in boxes. Check and make sure each bleeder is in the top side of the caliper. After that I would bleed it. I moonlighted at AutoZone to help pay for my kids classes. I had a man tell me the calipers were crap. He wanted to buy two more and would return the others once he got them off his truck. I asked if his truck was in the lot. After inspection of his calipers I told them they were on the wrong sides. He insisted that I didn't know what I was talking about. Finally he says why are they not marked? I said they are with the bleeder. I told him it was physics and common sense. He didn't like that. He left to switch them. He never returned. (More likely than swelling lines and simple to check)

2. Inspect the rubber lines. They can get tired and swell. Have someone pump the brakes while you hold the line. I prefer to wrap a ziptie tightly around the outside and then have someone pump the brakes. It makes it easier to differentiate between the line moving and actual swell. (Least likely easier to inspect than bleeding)

3. Inspect for new lines. I can't honestly tell you how many bad flares I have fixed from other shops. It may only weep a slight amount of fluid but suck air. If it has a new line it's worth inspecting each end. (No probability if there isn't new lines installed)

4. Bleed your system. Start at the master cylinder. Have some one pump the brakes up and hold them. Crack each line coming off the master cylinder. It will weep fluid out. Do this several times. Then move to the right rear or passenger rear. Then the driver rear. Then the passenger front then the driver front. (Likely the problem)
Front calipers and hoses appear to be new and they are correct in reference to bleeder.

Thx.
 

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Discussion Starter · #14 ·
KurtfromLaQuinta said:
Have you ever "bench bleed" the master cylinder?
Do you know how to do that?
You said you took it off and inspected it.
One of the problems I had in the past was not "bench bleeding " the m/c.
It was full of air. When I performed the bleeding, I could see bubbles of air returning into the fluid wells.
Yes. Bleeding systems and MCs is not a problem.
 

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Discussion Starter · #15 ·
dodge82273 said:
if you think about HOW the system works , logic dictates that miss-adjusted or poor fitting shoes and pads cause a "low" pedal . because liquid WILL NOT compress , and AIR will compress , air causes a soft pedal . Now in service what happens is a blending of both symptoms . if you had good brakes , and changed out 1 hydraulic part , allowing air INTO system , you'd KNOW it was an air problem , if you had good brakes and changed just shoes ,not opened the hydraulic system , and had a low/seems soft pedal , you'd know it was a fitment / adjustment problem. Because every thing has been changed /touched/opened , and YOU never had good brakes with it , start from the beginning . work your way thru it and have the confidence knowing you have safe brakes when its done .
hell even stuff like real loose front wheel bearing can cause those symptoms ... to some degree .. it is what it is .
Thx. My main goal with the thread was to set my expectation of brake performance and pedal feel. The truck is new to me and the brakes are not good. Your right, I need to start over.

Only troubleshooting I did prior to the thread was bleed the system and check bleeder orientation. Neither of those helped. Now I'm in the process of pulling the system apart and inspecting everything. Once it's re-assembled everything will be properly bled.

I'll report back what I find.
 

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yes , my first reply addressed your main goal .  and added reasons just in case some one reading  needed them . the prop/combo valve can be troublesome on these . Some turn out higher pedal than others ,  all should be firm , none very low .  low and soft =  no good , your right about that , its not a trait of these trucks .
 

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One of the things I love about the Dodge trucks of this era is the hard and short brake pedal. I recall driving a few other trucks in H.S. - mainly square-body Chevy's and Fords - and I remember just how squishy my bud Lou's K10 brakes were. The same as my dad's old 81 Bronco - I swear the brakes never even started to grab until you were 3/4 the way down and at that point, it hit abruptly (he was an ASE Master Tech and the truck was well maintained - just a terrible setup as his ~88 and 93 Broncos were all about the same).

To add to what others have said, it most certainly seems like an air problem, possibly related to your M/C removal. When I swapped from 1/2 ton axles to a set of 1-tons, I had some issue getting the rears to bleed, which was ultimately preventing me from getting any pedal since the combo valve was holding off fluid flow to the fronts. I eventually tracked it down to clogged bleeders in the D70, which were replaced and then the system was successfully bled. However, I've had or helped on similar issues to yours in the past and 90% of the time it was a M/C that had a bubble trapped.

Keep us updated!
 

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One other thought comes to mind. Many of the new masters need to have the rod between the booster, and master adjusted.

How I check it, is to loosen the bolts that hold the master, so a few threads show on each bolt.

The master should stay against the booster, or take very little to hold it there. If not, the riod is too long.

Then with the engine off, watch the master, as you press on the brake pedal. with the slightest movement of the pedal, the master should move.

If the pushrod is not rusted (thank you Pa), you can adjust it by removing the master (leave the lines connected, either use some rope, or get someone to hold it for you), with a pair of long nose pliers, hold the body of the rod, and with another pair of pliers, turn the tip in or out.

I adjust it outward, until you can feel the master piston moving when pushed against the booster, then back off 1/2 turn or so, so you do not feel the piston moving.


I would also take a look at the rear brakes, looking for full contact of the shoes, to the drum, and that they are adjusted properly. Self adjusters should turn, and the adjusting parts are in place, and on the rights sides.
 

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SuperBurban said:
One other thought comes to mind. Many of the new masters need to have the rod between the booster, and master adjusted.

How I check it, is to loosen the bolts that hold the master, so a few threads show on each bolt.

The master should stay against the booster, or take very little to hold it there. If not, the riod is too long.

Then with the engine off, watch the master, as you press on the brake pedal. with the slightest movement of the pedal, the master should move.

If the pushrod is not rusted (thank you Pa), you can adjust it by removing the master (leave the lines connected, either use some rope, or get someone to hold it for you), with a pair of long nose pliers, hold the body of the rod, and with another pair of pliers, turn the tip in or out.

I adjust it outward, until you can feel the master piston moving when pushed against the booster, then back off 1/2 turn or so, so you do not feel the piston moving.

I would also take a look at the rear brakes, looking for full contact of the shoes, to the drum, and that they are adjusted properly. Self adjusters should turn, and the adjusting parts are in place, and on the rights sides.
That is one thing I did not look at. Never even thought about it. Not only that, but, I swapped on a W300 booster and master cylinder as well. If that's the issue with my low pedal, would the rod need to be adjusted out or forward?
 

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J10Mike said:
That is one thing I did not look at. Never even thought about it. Not only that, but, I swapped on a W300 booster and master cylinder as well. If that's the issue with my low pedal, would the rod need to be adjusted out or forward?
I think of it as longer, or shorter, since the tip unscrews to make it longer. But you could also think of it as forward( longer, outward, ect), as you are taking up the space between the rod, and inside of the master. Here is a pic I snagged off the web. IIRC, Dodges are inside the booster a bit more then this pic.
 

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