Brake Booster Question
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New User
Joined: Sep 2006
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Brake Booster Question
78' 250
400 2bbl
HD drive train? (full floaters, dual piston calipers)
Having trouble with brakes. Very spongey on first pump. Completely rebuilt entire brake system including used booster. New drums, shoes, pads, cylinders, calipers, rotors, lines, MC. Pushed pin on prop. valve and gravity bled until clear fluid at each wheel. Imagine my frustration when I ended up with the same resuts afterwards. If I have the dual piston calipers do I need the f350 booster? I know the truck the current booster came off of had single piston calipers. Is there a difference between the boosters? I have plenty of vacuum at the booster and good brakes on the second pump...but I sure wouldn't want to have to stop fast on the first pump! It's hard to know on these "heavy duty" 250's which parts are 250's and which are 350's.
Thanks three quarters of a ton!
Ray
p.s. - This is truly an awesome site for info!
400 2bbl
HD drive train? (full floaters, dual piston calipers)
Having trouble with brakes. Very spongey on first pump. Completely rebuilt entire brake system including used booster. New drums, shoes, pads, cylinders, calipers, rotors, lines, MC. Pushed pin on prop. valve and gravity bled until clear fluid at each wheel. Imagine my frustration when I ended up with the same resuts afterwards. If I have the dual piston calipers do I need the f350 booster? I know the truck the current booster came off of had single piston calipers. Is there a difference between the boosters? I have plenty of vacuum at the booster and good brakes on the second pump...but I sure wouldn't want to have to stop fast on the first pump! It's hard to know on these "heavy duty" 250's which parts are 250's and which are 350's.
Thanks three quarters of a ton!
Ray
p.s. - This is truly an awesome site for info!
New User
Joined: Jan 2008
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When doing the F350 brake booster swap people are supposed to have single piston brake calipers.
People are also supposed to use the F350 PPV and the F350 Master cylinder.
There is a special attention to this in the article as the pressure vs line and piston size have to match the F350 system.
Plus, the F350 Booster pushrod is supposed to be set at the F350 push rod adjustment .
http://www.clubfte.com/users/mil1ion...trations2.html
Also, whas this F350 Booster Tested to verify it works and doesn't leak ?
Have to done any booster tests
People are also supposed to use the F350 PPV and the F350 Master cylinder.
There is a special attention to this in the article as the pressure vs line and piston size have to match the F350 system.
Plus, the F350 Booster pushrod is supposed to be set at the F350 push rod adjustment .
http://www.clubfte.com/users/mil1ion...trations2.html
Also, whas this F350 Booster Tested to verify it works and doesn't leak ?
Have to done any booster tests
Thread Starter
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New User
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I gave bad info i think
The booster came off another f250 4x4, not a 350. I'm just wondering if ford calls for a 350 booster when using dual piston calipers on a 250. I did check the push rod adjustment and set it for the 250 numbers, according to the Ironworks cd-rom I purchased (which is completely awesome by the way). I did check the booster with soap and there are no leaks. I am able to pull the push rod with the rubber gasket out of the booster. I wasn't sure if I should be able to do this or not. I guess what I'm wondering is did ford use the 350 booster on the 250 when dual pistons were used?
Thanks!
Thanks!
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try it
I'll try the back brakes. I have bled the system til I was blue in the face. I learned today that the two piston calipers do require a different booster on the 250, and its not the same part number as the standard 350 booster. Interesting. Are there certain areas where air is known to get trapped?
Junior User
Joined: Aug 2006
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Originally Posted by raygussy
The booster came off another f250 4x4, not a 350. I'm just wondering if ford calls for a 350 booster when using dual piston calipers on a 250. I did check the push rod adjustment and set it for the 250 numbers, according to the Ironworks cd-rom I purchased (which is completely awesome by the way). I did check the booster with soap and there are no leaks. I am able to pull the push rod with the rubber gasket out of the booster. I wasn't sure if I should be able to do this or not. I guess what I'm wondering is did ford use the 350 booster on the 250 when dual pistons were used?
Thanks!
Thanks!
I have dual piston calipers and do not have a 350 brake booster on my 79 f-250. The master cylinder is different than your single piston system, but the booster is still the large size one.
If you continue to have a spongy pedal, you may have to have your system power bled.
Posting Legend
Joined: Sep 2001
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There is an old thread in the Garage forum on making a pressure bleeder. Other than that the vacuum types work fairly well unless you pull too much vacuum and air gets pulled in past the seals. -Been there done that.
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The booster for a F250 is the regular booster.
I assume this isn't the original brakes as the 78 F250 never had dual-piston calipers,they all had single piston calipers.
Dual piston calipers ended in 76.
I don't know here you got that info but AFAIK,You do NOT need to use the F350 booster for dual piston calipers.
Please tell me where you got that info
BTW, You didn't say if it was a 4x2 or 4x4.
You can look it up yourself here:
http://www.precisionrebuilders.com/p...ogPHB-0398.pdf
The well known brake/booster swap article on this site mentions ...involving the removal the dual piston calipers from a Bronco and swapping in the large car single piston calipers.
I assume this isn't the original brakes as the 78 F250 never had dual-piston calipers,they all had single piston calipers.
Dual piston calipers ended in 76.
I don't know here you got that info but AFAIK,You do NOT need to use the F350 booster for dual piston calipers.
Please tell me where you got that info
BTW, You didn't say if it was a 4x2 or 4x4.
You can look it up yourself here:
http://www.precisionrebuilders.com/p...ogPHB-0398.pdf
The well known brake/booster swap article on this site mentions ...involving the removal the dual piston calipers from a Bronco and swapping in the large car single piston calipers.
Last edited by Mil1ion; Sep 11, 2006 at 03:19 PM.
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First off clamp off the three brake hoses. Is the pedal rock hard now??. If it is release one clamp at a time until the problem returns. If its in the rears it is probably adjustment or air. If its in the fronts it may be air or wrong vulume of master bore for the dual piston calipers. Also make sure the pistons are not retracting too far.
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Calipers
So they stopped using dual pistons in 1976? That seems weird because if you go to Autozone's or NAPA's or Advance's website and do the search for booster on a 78 F250 they ask if the truck has single or dual piston calipers. And there definitely is duals on the truck, I put them on. I like the hose clamping idea, that seems like a great way to tell where the problem is. There isn't a chance that the dual piston calipers would fit on the 78 but not supposed to be used is there? Any advice would be great!
Thanks
Thanks
