braking problems remain.....
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From: Sonora
braking problems remain.....
Last time I was here, I was having problems getting my brakes to work after a total overhaul on the braking system. Well, I finally got some time off to continue my quest and I am at a standstill. I have taken the M/C off twice to make sure it is bled, and I have bled the whole system at least as many times. The only thing I can think of is if the porp. valve has to be bled. Does it? Is there anything I have missed? It's a 70 F-250 w/ pwr brakes. In case you missed it the last time, the brakes go all the way to the floor before they even begin to work. Even then they only work slightly. I have the brakes adjusted as snug as I can go. As a matter of fact, the LR wheel locks up slightly when I hit the brakes all the way. Any suggestions before I take it to the shop? I'm out of ideas and frankly I'm sick of messing with it. I'm sure y'all can relate. TIA Bill
Nuthin' outruns my V-8 Ford -Chuck Berry STOPPING IS THE PROBLEM!!!:-) ha ha ha
Nuthin' outruns my V-8 Ford -Chuck Berry STOPPING IS THE PROBLEM!!!:-) ha ha ha
Tuned
Joined: Feb 2000
Posts: 309
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From: michigan
braking problems remain.....
what's up Bill, i haven't seen any of your other posts on this problem, so atleast i'm assuming you have replaced the brake booster also. now i'm not sure about the 1970 pickup, but it's worth a look to see if you have one. i've got a 77 F-150 4X4 and when i went through my brakes also. now when it came to bleeding them in one repair manual on these trucks there is a valve on the front of the prop. valve that needs to be pulled out to bleed the front brakes. crawl under your truck and look at the front of the prop. valve there should be a little valve (it looks like a small nipple ) if you have one it should able to pull it out, now it only comes out a little bit. i didn't have a clip made up to hold it so i used a pair of pliers to hold the valve open with one hand and i used a pair of small vise grips to clamp onto the valve stem with the other hand to hold it open during bleeding. and after bleeding return the valve to it's original position. something to look for and try. Ray....
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From: Sonora
braking problems remain.....
Thanks Ray, I thought the porp valve might need to be bled, it only makes sense. But there's so much muck on the frame I couldn't see a nipple on it. That might be the problem. The booster is fine. I last posted on this probably a month ago. Thanks again! Bill
Nuthin' outruns my V-8 Ford - Chuck Berry
Ps I'll try tomorrow and post results. Now, do I have to bleed the whole system again? Or since I just did it, can I bleed JUST the porp valve?
Nuthin' outruns my V-8 Ford - Chuck Berry
Ps I'll try tomorrow and post results. Now, do I have to bleed the whole system again? Or since I just did it, can I bleed JUST the porp valve?
Posting Guru
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From: Inthepast
braking problems remain.....
[FONT COLOR="#0000ff" SIZE="3" FACE="Veranda"]
The 70 F250 with factory drum brakes on all four wheels does not have a proportioning valve, but rather a pressure differential valve. It does not need to be bled seperately. Taking your word that you have properly bled the brake system, I suspect you have excess pedal travel due to the incorrect MC rod or improper adjustment of the plunger between the MC and the booster. How far does your pedal move until you can feel the MC engage (try determining this distance using your hand to actuate the pedal, truck not running). Report back.
[/FONT]
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The 70 F250 with factory drum brakes on all four wheels does not have a proportioning valve, but rather a pressure differential valve. It does not need to be bled seperately. Taking your word that you have properly bled the brake system, I suspect you have excess pedal travel due to the incorrect MC rod or improper adjustment of the plunger between the MC and the booster. How far does your pedal move until you can feel the MC engage (try determining this distance using your hand to actuate the pedal, truck not running). Report back.
[/FONT]
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From: Sonora
braking problems remain.....
Stockman, see that's the funny thing. With the engine off, the brakes feel fine. They are solid and seem to engage as soon as you step on the pedal, or maybe an inch or so of free-play. It seems to me that the problem lies in the front half of the system, because as I said the rears will lock up if I really stomp on the pedal. But when I start the engine, the pedal goes nearly to the floor. The brakes work during maybe the last inch or two of travel. TIA Bill
Nuthin' outruns my V-8 Ford - Chuck Berry
Nuthin' outruns my V-8 Ford - Chuck Berry
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From: Inthepast
braking problems remain.....
[FONT COLOR="#0000ff" SIZE="3" FACE="Veranda"]
The reason I said, "not running" is that you can easily tell the free play by hand. An inch is a lot. I have the 67 spec as 3/16"-3/8" (yours should be the same). This could be part of the problem. Also, I was curious if your pedal height inproves any after several pumps of the pedal in succession? If so, that's a sign of air. I'd add that you could also have a bad MC. If it's a reman., it wouldn't be the first one that failed off the shelf. These type problems are frustrating, I know. Stick with it. If you were close, I'd bring by your favorite legal beverage and offer a hand.
[/FONT]
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The reason I said, "not running" is that you can easily tell the free play by hand. An inch is a lot. I have the 67 spec as 3/16"-3/8" (yours should be the same). This could be part of the problem. Also, I was curious if your pedal height inproves any after several pumps of the pedal in succession? If so, that's a sign of air. I'd add that you could also have a bad MC. If it's a reman., it wouldn't be the first one that failed off the shelf. These type problems are frustrating, I know. Stick with it. If you were close, I'd bring by your favorite legal beverage and offer a hand.
[/FONT]
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From: Sonora
braking problems remain.....
[font size="1" color="#FF0000"]LAST EDITED ON 20-Jan-01 AT 10:36 PM (EST)[/font][p]You know, come to think of it, I think the pedal does pump up, but VERY little. If there is air in there, I can't figure out where it is and how to get it out. I think it's time to face the inevitable-and take it to the S...H...O...P...how depressing.:-(
Nuthin' outruns my V-8 Ford - Chuck Berry
Yahoo! I'm official now. I hit 100 posts! I feel so omnipotent!!:-)
Nuthin' outruns my V-8 Ford - Chuck Berry
Yahoo! I'm official now. I hit 100 posts! I feel so omnipotent!!:-)
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Posting Guru
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From: Inthepast
braking problems remain.....
[FONT COLOR="#0000ff" SIZE="3" FACE="Veranda"]
Don't give up just yet. The shop will charge you at least $50-100 as a minimum. Consider investing in a vacuum bleeder or perhaps run another sequence of fluid through the reservoir. :-)
It won't be as bad as it sounds. I also have good luck with gravity bleeding. Open the bleeders one at a time for an hour or so. Start at the farthest wheel and work to the closest. Be sure to watch that the reservoir is kept full![/FONT]
[LINK:www.hometown.aol.com/tbeeee|http://members.aol.com/tbeeee/page/registrysig.gif]
Don't give up just yet. The shop will charge you at least $50-100 as a minimum. Consider investing in a vacuum bleeder or perhaps run another sequence of fluid through the reservoir. :-)
It won't be as bad as it sounds. I also have good luck with gravity bleeding. Open the bleeders one at a time for an hour or so. Start at the farthest wheel and work to the closest. Be sure to watch that the reservoir is kept full![/FONT]
[LINK:www.hometown.aol.com/tbeeee|http://members.aol.com/tbeeee/page/registrysig.gif]
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Thread Starter
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Junior User
Joined: Sep 2000
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From: Sonora
braking problems remain.....
I guess I'll try again tomorrow. I couldn't take it to the s#*! till Tuesday anyway. Thanks for the encouragement. Bill
Nuthin' outruns my V-8 Ford - Chuck Berry
Nuthin' outruns my V-8 Ford - Chuck Berry
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From: Sonora
braking problems remain.....
Well, I was wrong, the pedal DOESN'T pump up. Since the m/c was lifetime warranty, I took it back just to be sure it wasn't the problem. I got another NEW one (not remanufactured) and installed it. After bench bleeding, same problem. The pushrod sticks out a tad over 1" past the booster. I hear it's supposed to be .885", but I think shortening the rod would exacerbate the situation. I know there is no air in the lines because I use the clear tube into the bottle thingamajig and I see air bubbles come out on the first couple of pumps then just fluid. The only thing I can imagine is that I am bench bleeding the m/c incorrectly. I use the plastic plugs that come with the m/c and I follow the instructions to the "T". Sorry for the long post, I had to vent. :-) Bill
'70 F-250 360/C-6 3.73 8 mpg uphill or down
'70 F-250 360/C-6 3.73 8 mpg uphill or down
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From: Sonora
braking problems remain.....
[font size="1" color="#FF0000"]LAST EDITED ON 22-Jan-01 AT 02:09 AM (EST)[/font][p]I forgot to mention that when the engine is off, the pedal is very hard. Then as soon as I start it, they go to the floor. Does this help unravel the mystery any? Bill
'70 F-250 360/C-6 3.73 8 mpg uphill or down
P.S. I just saw that I already posted this info. Oh well...
'70 F-250 360/C-6 3.73 8 mpg uphill or down
P.S. I just saw that I already posted this info. Oh well...
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Junior User
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From: Sonora
braking problems remain.....
Good news! I just wanted to update this post, and let everyone know that I got my brakes working! I pulled the m/c off and re-measured the pushrod. It was already protruding over an inch. The spec, says .885" I unscrewed it about another 1/4" anyway and voila! It works. I am way over spec but I suspect the new m/c is slightly longer than the stock one. I know it's wider and a little deeper. In retrospect, I figure that's why the rear brakes were working and the fronts weren't. The pushrod wasn't making it to the front resevoir. Anyway, I just wanted to close out this post and thank everybody for your ideas and encouragement! Bill
'70 F-250 Camper Special 360/C-6 3.73 8 mpg uphill or down
'70 F-250 Camper Special 360/C-6 3.73 8 mpg uphill or down
Fleet Owner
Joined: Jun 1999
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From: Creedmoor, North Carolina
braking problems remain.....
Good news Bill, Glad to hear things are coming to a stop. ;-)
John
jowilker
Club FTE since 01 01
NC Chapter
66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.
John
jowilker
Club FTE since 01 01
NC Chapter
66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.
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