Brake help please-Rears lock, front don't.
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Junior User
Joined: Jan 2007
Posts: 84
Likes: 0
From: Arizona
Brake help please-Rears lock, front don't.
This is my setup:
53 F100
Ford master cylinder and power booster (from a Maverick?)
Adjustable proportioning valve
Front disks from a '95 Dodge Dakota
Rear drums on a Ford 9".
I have the proportioning valve turned down all the way which equals a 35% reduction.
Symptoms
The brakes grab really hard but, during hard braking the rears lock up and the fronts dont.
What I have tried
Adjusting the proportioning valve both ways.
What I don't know
Could fill a book...
I am not sure that the lines are plumbed correctly
The line at the front of the master goes to the rear brakes and the one at the rear goes to the front. I have wondered if it should be the other way around, but haven't found any pictures on the net that confirm or deny the thought.
I have heard that I can put an inline restricter to the rear brakes. I have searched some of the popular manufacturers (baer, wilwood, brembo, etc.) and haven't found any yet.
I am open to ideas and opinions... Help me if you can.
Sterling.
53 F100
Ford master cylinder and power booster (from a Maverick?)
Adjustable proportioning valve
Front disks from a '95 Dodge Dakota
Rear drums on a Ford 9".
I have the proportioning valve turned down all the way which equals a 35% reduction.
Symptoms
The brakes grab really hard but, during hard braking the rears lock up and the fronts dont.
What I have tried
Adjusting the proportioning valve both ways.
What I don't know
Could fill a book...
I am not sure that the lines are plumbed correctly
The line at the front of the master goes to the rear brakes and the one at the rear goes to the front. I have wondered if it should be the other way around, but haven't found any pictures on the net that confirm or deny the thought.
I have heard that I can put an inline restricter to the rear brakes. I have searched some of the popular manufacturers (baer, wilwood, brembo, etc.) and haven't found any yet.
I am open to ideas and opinions... Help me if you can.
Sterling.
Fleet Owner
Joined: Jul 2004
Posts: 27,294
Likes: 1,055
From: NM
Originally Posted by jmerson
Get a day job.
Originally Posted by Azls1
am not sure that the lines are plumbed correctly
The line at the front of the master goes to the rear brakes and the one at the rear goes to the front. I have wondered if it should be the other way around, but haven't found any pictures on the net that confirm or deny the thought.
The line at the front of the master goes to the rear brakes and the one at the rear goes to the front. I have wondered if it should be the other way around, but haven't found any pictures on the net that confirm or deny the thought.
Please clarify which is the "front" of the M/C, since it is likely facing backwards (like stock)
Last edited by ALBUQ F-1; Mar 10, 2007 at 07:04 PM.
Posting Guru
Joined: Mar 2003
Posts: 1,734
Likes: 2
From: Kansas City area
If you have the pedal assembly/booster/mc under the floor as in the original pedal location then you should have residual valves in the lines, 10 psi to the drums and 2psi to the disks. Wilwood is a common brand name and any street rod or hot rod supply store can furnish these. www.SpeedwayMotors.com has them and also a diagram of a typical system in their catalog.
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Elder User
Joined: May 2006
Posts: 907
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From: Kansas City, Mo
brakes
It's frosty time. I think all questions are good. I read every new thread each day. Some I know or have done in the past. Some I have forgotten or need a refresher. Some I've never tackled. I've installed a m/c near top of the firewall, but not under the floor (reference this article). I appreciate all reviews, starting very basic, there are always new builders and old/new me. Thanks to everyone who takes the time to enlighten us. Everyone have a great day, chuck
Last edited by 49fordpickumup; Mar 10, 2007 at 08:07 PM.
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Thread Starter
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Junior User
Joined: Jan 2007
Posts: 84
Likes: 0
From: Arizona
Here is a picture of the setup. I confirmed that the large resevoir is plumbed to the discs in the front.
From your replies I need to; find a day job and research a combination valve. If anyone wants to point me in the right direction I will appreciate it. Until then I'll search the site and the internet and see if I can get a degree in combination valves
From your replies I need to; find a day job and research a combination valve. If anyone wants to point me in the right direction I will appreciate it. Until then I'll search the site and the internet and see if I can get a degree in combination valves
Postmaster
Joined: Nov 2001
Posts: 3,351
Likes: 1
From: Escondido, CA
Here is a link that will help explain a majority of your questions as to why your rear brakes keep locking up. I have installed a combo valve from an online vendor, see pea pea(say it out loud), that cost $45. I haven't had any issues with sensitve brakes. I hope the link helps.http://auto.howstuffworks.com/master-brake2.htm
Last edited by airharley; Mar 10, 2007 at 11:33 PM. Reason: spelling
Lead Driver
Joined: Aug 2002
Posts: 6,682
Likes: 12
From: Saskatoon SK Canada
Your master cylinder is plumbed correctly. You don't necessarily need a combo valve. A combo valve just adds a warning light and a metering valve which delays the front disc till the rear brakes grab.
It all depends on your how "hard" your braking. If these are like a panic stop then what your experiencing is normal. Since there is very little weight in the rear of these trucks, it is much easier to lock the rear up. This is why many trucks just had rear ABS brakes. If I hit the brakes hard I can lock the rear brakes on my 4 wheel disc brakes on my car.
It all depends on your how "hard" your braking. If these are like a panic stop then what your experiencing is normal. Since there is very little weight in the rear of these trucks, it is much easier to lock the rear up. This is why many trucks just had rear ABS brakes. If I hit the brakes hard I can lock the rear brakes on my 4 wheel disc brakes on my car.
Thread Starter
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Junior User
Joined: Jan 2007
Posts: 84
Likes: 0
From: Arizona
Thank you guys. I found both sites and have a better understanding of what is required to run a big booster and a front disc rear drum set up.
Also the term "proportioning valve" was the key that helped me search the similar posts on this board regarding this topic.
I am kind of torn on this one. Under most circumstance the brakes work well.
It is panic stops and hard braking that will lock up the rears.
I do realize that the rear does get really light under these conditions. So, I guess I am having trouble determining what is acceptable.
I really appreciate those of you that have taken and are taking the time to help me with this one.
Also the term "proportioning valve" was the key that helped me search the similar posts on this board regarding this topic.
I am kind of torn on this one. Under most circumstance the brakes work well.
It is panic stops and hard braking that will lock up the rears.
I do realize that the rear does get really light under these conditions. So, I guess I am having trouble determining what is acceptable.
I really appreciate those of you that have taken and are taking the time to help me with this one.
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