Re: 70 b body braking issues.. The end I hope.
[Re: fastmark]
#3282665
01/14/25 03:34 PM
01/14/25 03:34 PM
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Joined: Feb 2003
Posts: 10,462
Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 10,462
Someplace you aren't
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I don’t know what was in the other thread.
New hoses? Also brand new and not nos?
Gravity bleed to see if you see air coming in the jar? Really a one man bleeder would reveal it though.
I want my fair share
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Re: 70 b body braking issues.. The end I hope.
[Re: SomeCarGuy]
#3282669
01/14/25 04:11 PM
01/14/25 04:11 PM
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Joined: Jan 2003
Posts: 22,188
A collage of whims
topside
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 22,188
A collage of whims
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What I recall from older Mopars with PB is that the pedal seemed "softer" than manual brakes, with more travel, almost to bottoming.
Last bit of travel was the braking action.
Those were stock cars, not big-cammed, low-vacuum deals.
If you can lock up the ft tires, that's about nominal.
My racer buddy somehow gets the firmest, best-feeling brakes of anyone I've met - he bleeds the heck out of them, past where I don't see bubbles.
Always goes RR, LR, RF & LF.
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Re: 70 b body braking issues.. The end I hope.
[Re: fastmark]
#3282760
01/14/25 11:24 PM
01/14/25 11:24 PM
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Joined: Jan 2003
Posts: 16,278
Omaha Ne
TJP
I Live Here
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I Live Here
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Posts: 16,278
Omaha Ne
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Done all that. New hoses not NOS. Bled it so much I own stock in dot 5 brake fluid. I’ve thought about a pressure bleeder but all I’ve done is have a friend pump and hold method. It has never failed. My AAR does not bottom out. It stops like you hit a wall. Booster works fine three different MC. Rebuilt combo and metering valve, etc., etc. Dot 5 can be a bit tricky in that it Aerates if moved to quickly when bleeding. if using the pump and hold method, Pump slowly or just depress the pedal somewhat slowly. While holding the pedal down crack the bleeder slowly until the fluid starts coming out (slowly) Close the bleeder before the fluid stops moving. Repeat. Even when using a pressure bleeder one has to bleed slowly. You can also try gravity bleeding. I wehn not using a pressure bleeder, I have occasionally needed re-bench bleed the master. reinstall on car. Have helper depress pedal while cracking open both front and rear lines going into the porp valve. Close before fluid stops. Repeat severa times. This prevents air in the front line from beiing sucked back into the master while bleeding at the rears. With DOT 5 SLOW is required Pour some dot 5 in a small air brush jar, cap it and shake it 
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Re: 70 b body braking issues.. The end I hope.
[Re: fastmark]
#3282793
01/15/25 08:43 AM
01/15/25 08:43 AM
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Joined: Jan 2003
Posts: 75,418
A gulag near you.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,418
A gulag near you.
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I’ve wondered if the dot 5 may been the issue. Everything I’ve done has helped a little but it has not been totally cured. I’ve never gravity bled. I’m assuming you just crack the bleeder in the wheel and let it drip into a bottle? How about reverse bleeding? I’ve heard of that but never done it. Does the AAR have Dot 5 ?
Mainstream Media is the new Pravda
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Re: 70 b body braking issues.. The end I hope.
[Re: JohnRR]
#3282807
01/15/25 10:06 AM
01/15/25 10:06 AM
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Joined: Jun 2005
Posts: 5,217
Western Md.
skicker
"The Champ"
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"The Champ"
Joined: Jun 2005
Posts: 5,217
Western Md.
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On my 70 Satellite I have 87 Diplomat Spindles and typical 10" rear drums... The master is a 15/16" two bolt with the adapter from Doctor Diff... The pedal has always been long but the brakes work really well... On my 69 Dart I have the 73-76 A body spindles and typical 10" rear drums... The master is a 15/16" two bolt with the adapter from Doctor Diff... The pedal has always been firmer and the brakes work remarkably well...most all braking at the top of the pedal... Both cars have the same proportioning valve from a manual/disc 73-73 A body... Both cars are manual brake with virtually the same components which were all brand new at the time of construction and both on Dot 3... Biggest difference is the curb weight as the Satellite is considerably heavier... I often wonder if it may need a 1" master on the Satellite to increase the volume and firm up the pedal... It has been bled and bled sometimes a year or so apart with never any changes in pedal travel and feel... 
...FAFO...
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Re: 70 b body braking issues.. The end I hope.
[Re: fastmark]
#3282822
01/15/25 11:51 AM
01/15/25 11:51 AM
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Joined: Feb 2003
Posts: 10,462
Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 10,462
Someplace you aren't
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I’ve wondered if the dot 5 may been the issue. Everything I’ve done has helped a little but it has not been totally cured. I’ve never gravity bled. I’m assuming you just crack the bleeder in the wheel and let it drip into a bottle? How about reverse bleeding? I’ve heard of that but never done it. It’d only be an issue if it has air. I converted my 69 GTX last year. Manual drums all around. I did new hoses upfront. One new wheel cylinder. Project took longer than I wanted, so left the rear hose dated 2016 to change this year. I flushed the dot 3 out by myself with a cheap one man bleeder. I simply pushed the pedal slowly as I could, never bottomed out. That’s all the more I did. I think I took it further towards end of travel towards the end of the job as I was confident the dot3 was out and had yet to see any air after the start. Ran about a full pint in each end of the system. Started at left front to get the air out of the system there as it was all new, then did rf because it had the new hose. Didn’t like the idea of all that air being in there and doing the rear first. Finished by going rr, couldn’t get it to run purple all the way. Figured it was transmix from lr. So did that side until purple. Then went back and did my standard rr, lr, rf, lf just like always. Absolute rock hard pedal, as good as any vehicle I’ve ever driven. I want to stress I did this slowly. Maybe to the point people wouldn’t have the patience. I bought the dot5 off amazon, if that matters. White bottle. Johnson brand I think. Let is sit for a few days before use, poured slowly and deliberately too. Bleeder kit is cheap ten dollar thing from Autozone. I drove the wheels off the car last season. Never an issue.
I want my fair share
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Re: 70 b body braking issues.. The end I hope.
[Re: topside]
#3282829
01/15/25 12:36 PM
01/15/25 12:36 PM
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Joined: Jan 2003
Posts: 27,359
Rio Linda, CA
John_Kunkel
The Erection Connection
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The Erection Connection
Joined: Jan 2003
Posts: 27,359
Rio Linda, CA
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What I recall from older Mopars with PB is that the pedal seemed "softer" than manual brakes, with more travel, almost to bottoming.\ Single piston floating calipers will cause a softer pedal...almost bottoming sounds like the MC bore is too small. When the pedal is near bottoming, if pumping the pedal a couple of times rapidly will bring the pedal up, the bore is too small.
The INTERNET, the MISinformation superhighway
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Re: 70 b body braking issues.. The end I hope.
[Re: John_Kunkel]
#3282889
01/15/25 04:23 PM
01/15/25 04:23 PM
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Joined: Jan 2003
Posts: 11,041
Freeport IL USA
poorboy
I Live Here
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I Live Here
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Posts: 11,041
Freeport IL USA
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If the braking action is mostly at the bottom end of the pedal stroke (or way at the top of the pedal), there is an adjustment on the end of the push rod between the master cylinder and the booster to adjust the amount of free play in the pedal movement. You need to pull the master away from the booster to gain access, no need to disconnect the brake lines from the master. Just unbolt the master from the booster and pull it to the side. On the end of the push rod that acts as the plunger into the master cylinder, there should be a small rounded threaded end with a lock nut that is screwed into the rod's body. Simply loosen the lock nut, and turn the the rounded end outward 1/4 turn and tighten the lock nut again to reduce the free play at the top of the pedal (turning the end in will increase the end free play).
Do not get carried away, a little adjustment here makes a large difference in the free pedal travel.
Once you have made the 1/4 turn adjustment and have tightened the lock nut, bolt the master cylinder back on and test how far the pedal travel has changed. If desired, you can remove the master and take another 1/4 turn out in the adjustment process. I strongly suggest you take up the free play in small adjustments, rather then a lot at once.
When the lock nut is loosened, turning the end out reduces the free play. Turning the end in increases the free play. This adjustment is available because of the different depths some master pistons have where the push rod makes contact.
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Re: 70 b body braking issues.. The end I hope.
[Re: JohnRR]
#3282991
01/16/25 08:06 AM
01/16/25 08:06 AM
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Joined: Jan 2003
Posts: 6,727
Abilene, Texas
fastmark
OP
master
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OP
master
Joined: Jan 2003
Posts: 6,727
Abilene, Texas
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I’ve wondered if the dot 5 may been the issue. Everything I’ve done has helped a little but it has not been totally cured. I’ve never gravity bled. I’m assuming you just crack the bleeder in the wheel and let it drip into a bottle? How about reverse bleeding? I’ve heard of that but never done it. Does the AAR have Dot 5 ? It has dot 5. All the cars I work on end up with dot 5. I worked a restored 68 Charger with factory disc brakes and rebuilt booster. The guy had his original master cly sent off to be sleeved and they just honed it out instead. The shop had used dot 3 and it leaked inside this guy’s storage for three years. It destroyed the new paint. I fixed the mess and used a repop master with dot 5 and it worked great. I had another friend with a $100,000 restoration use dot five and it leaked all over his car. Same deal with his paint. I just wont use anything else but dot 5.
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Re: 70 b body braking issues.. The end I hope.
[Re: skicker]
#3282992
01/16/25 08:17 AM
01/16/25 08:17 AM
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Joined: Jan 2003
Posts: 6,727
Abilene, Texas
fastmark
OP
master
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OP
master
Joined: Jan 2003
Posts: 6,727
Abilene, Texas
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On my 70 Satellite I have 87 Diplomat Spindles and typical 10" rear drums... The master is a 15/16" two bolt with the adapter from Doctor Diff... The pedal has always been long but the brakes work really well... On my 69 Dart I have the 73-76 A body spindles and typical 10" rear drums... The master is a 15/16" two bolt with the adapter from Doctor Diff... The pedal has always been firmer and the brakes work remarkably well...most all braking at the top of the pedal... Both cars have the same proportioning valve from a manual/disc 73-73 A body... Both cars are manual brake with virtually the same components which were all brand new at the time of construction and both on Dot 3... Biggest difference is the curb weight as the Satellite is considerably heavier... I often wonder if it may need a 1" master on the Satellite to increase the volume and firm up the pedal... It has been bled and bled sometimes a year or so apart with never any changes in pedal travel and feel... Both of my cars have the factory NOS casting master cly. The AAR has the rare 171 casting and is a 1” bore. The Charger has the rare engine side casting, 821 I think, master. The b body is 1.125” bore. I think DoctorDiff says to use the 15/16” to firm UP the pedal. I’m not sure but I want to use oem type parts on these restorations. I’ve installed three of the repop boosters, masters, and combo valve from DoctorDiff on customers cars and never had this problem.
Last edited by fastmark; 01/16/25 08:33 AM.
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Re: 70 b body braking issues.. The end I hope.
[Re: SomeCarGuy]
#3282994
01/16/25 08:23 AM
01/16/25 08:23 AM
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Joined: Jan 2003
Posts: 6,727
Abilene, Texas
fastmark
OP
master
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OP
master
Joined: Jan 2003
Posts: 6,727
Abilene, Texas
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I’ve wondered if the dot 5 may been the issue. Everything I’ve done has helped a little but it has not been totally cured. I’ve never gravity bled. I’m assuming you just crack the bleeder in the wheel and let it drip into a bottle? How about reverse bleeding? I’ve heard of that but never done it. It’d only be an issue if it has air. I converted my 69 GTX last year. Manual drums all around. I did new hoses upfront. One new wheel cylinder. Project took longer than I wanted, so left the rear hose dated 2016 to change this year. I flushed the dot 3 out by myself with a cheap one man bleeder. I simply pushed the pedal slowly as I could, never bottomed out. That’s all the more I did. I think I took it further towards end of travel towards the end of the job as I was confident the dot3 was out and had yet to see any air after the start. Ran about a full pint in each end of the system. Started at left front to get the air out of the system there as it was all new, then did rf because it had the new hose. Didn’t like the idea of all that air being in there and doing the rear first. Finished by going rr, couldn’t get it to run purple all the way. Figured it was transmix from lr. So did that side until purple. Then went back and did my standard rr, lr, rf, lf just like always. Absolute rock hard pedal, as good as any vehicle I’ve ever driven. I want to stress I did this slowly. Maybe to the point people wouldn’t have the patience. I bought the dot5 off amazon, if that matters. White bottle. Johnson brand I think. Let is sit for a few days before use, poured slowly and deliberately too. Bleeder kit is cheap ten dollar thing from Autozone. I drove the wheels off the car last season. Never an issue. This actually makes more sense than anything else. Fast pumping may be the problem.
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Re: 70 b body braking issues.. The end I hope.
[Re: John_Kunkel]
#3282995
01/16/25 08:32 AM
01/16/25 08:32 AM
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Joined: Jan 2003
Posts: 6,727
Abilene, Texas
fastmark
OP
master
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OP
master
Joined: Jan 2003
Posts: 6,727
Abilene, Texas
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What I recall from older Mopars with PB is that the pedal seemed "softer" than manual brakes, with more travel, almost to bottoming.\ Single piston floating calipers will cause a softer pedal...almost bottoming sounds like the MC bore is too small. When the pedal is near bottoming, if pumping the pedal a couple of times rapidly will bring the pedal up, the bore is too small. Pumping the pedal does not help at all. It usually does when you have air in the system or the rears are not adjusted correctly. I’ve tighten up the rears until they were too tight and it did not help. The b body has the 1.125 bore while the ebody is the 1”.
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Re: 70 b body braking issues.. The end I hope.
[Re: poorboy]
#3283001
01/16/25 08:58 AM
01/16/25 08:58 AM
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Joined: Jan 2003
Posts: 6,727
Abilene, Texas
fastmark
OP
master
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OP
master
Joined: Jan 2003
Posts: 6,727
Abilene, Texas
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If the braking action is mostly at the bottom end of the pedal stroke (or way at the top of the pedal), there is an adjustment on the end of the push rod between the master cylinder and the booster to adjust the amount of free play in the pedal movement. You need to pull the master away from the booster to gain access, no need to disconnect the brake lines from the master. Just unbolt the master from the booster and pull it to the side. On the end of the push rod that acts as the plunger into the master cylinder, there should be a small rounded threaded end with a lock nut that is screwed into the rod's body. Simply loosen the lock nut, and turn the the rounded end outward 1/4 turn and tighten the lock nut again to reduce the free play at the top of the pedal (turning the end in will increase the end free play).
Do not get carried away, a little adjustment here makes a large difference in the free pedal travel.
Once you have made the 1/4 turn adjustment and have tightened the lock nut, bolt the master cylinder back on and test how far the pedal travel has changed. If desired, you can remove the master and take another 1/4 turn out in the adjustment process. I strongly suggest you take up the free play in small adjustments, rather then a lot at once.
When the lock nut is loosened, turning the end out reduces the free play. Turning the end in increases the free play. This adjustment is available because of the different depths some master pistons have where the push rod makes contact. This procedure of adjusting the pushrod is not the same as most master cly. This adjustment is not mentioned in any service manual from 68-71 that I own. You are correct to check this if it was the ebody master cly because it is held in the correct position by a stop held in place by a screw on the face that bolts to the booster. I have the tool to do that. The 67-70 b body master has a piston that is held in place by a bolt in the bottom of the master cly. The primary piston protrudes out of the back almost enough to expose the rear seal. The booster rod is supposed to set the primary piston in the correct position by pushing it back in the bore to the correct position that is almost flush. This correct position is discussed in the 1970 Master Tech training class bulletin I’ve discussed before. The piston seals need to be positioned slightly behind the compensator port into the reservoir . If it is too far behind this port, all you are doing with this longer stroke is pushing fluid right back into the reservoir until it passes this port and starts builds pressure. If the seal is set too far past the port, it will never let all of the air out of the master cly. One the the aftermarket masters I tried had an incorrect piston that never uncovered this port for the rear and it caused this problem. I’ll post pictures of this but I discussed this on one of my earlier threads.  
Last edited by fastmark; 01/16/25 09:02 AM.
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Re: 70 b body braking issues.. The end I hope.
[Re: fastmark]
#3283003
01/16/25 09:11 AM
01/16/25 09:11 AM
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Joined: Jan 2003
Posts: 6,727
Abilene, Texas
fastmark
OP
master
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OP
master
Joined: Jan 2003
Posts: 6,727
Abilene, Texas
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You can read this entire Master Tech training bulletin on ebodies.org. It is very helpful. As you can see and read, no pressure starts to build until after the piston PASSES the compensator port. So, if you adjust the booster rod to the the master cly off the car, on the 68-70 b body master, with clearance, all you are doing is squirting fluid back into the reservoir, not building pressure and wasting part of your stroke.
I’ve bolted my NOS master cly to the vice and watched though the compensator port as I push on the primary piston. It takes approximately .125” to be in the correct position. This is from memory. I’d have to look at my notes to be exact.
Here are the two masters I’m dealing with. The first one is my other NOS 171 for the ebody held flush in place by the screw. The second is another NOS for the 70 B body. Notice where the piston sticks out the the point that the rear seal is slightly exposed. Notice in the Master tech article that the prim piston is flush and the comp port is in the correct position. I have verified this visually in the vice off the car.
Last edited by fastmark; 01/16/25 09:28 AM.
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