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Discussion Starter #1
Hello everyone, I have a persistent issue that I cannot make go away with my braking system. I have exhausted everything that I could think of to resolve the situation but no luck.

I was reading this post http://www.fordmuscleforums.com/all-ford-techboard/511041-brake-bleeding-issues-5.html on-line and it seemed to me some very knowledgeable people involved.

I would appreciate any help, maybe its best that I post all the details but doing this in the past on other forums has led to people complaining the post was too long and then no help because they dont want to read a long post.

With that said let me ask, is it possible that instead of my rear brakes working as they should that instead the fluid is just bypassing within the master cylinder like what it did when I bench bled it because the spring pressure or whatever was just stronger on the shoes?

I have a Frankenstein of parts on this vehicle which may seem complicated so that is why it would be a long post to name all the details. Thanks for your time
 

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Hello everyone, I have a persistent issue that I cannot make go away with my braking system. I have exhausted everything that I could think of to resolve the situation but no luck.

I was reading this post http://www.fordmuscleforums.com/all-ford-techboard/511041-brake-bleeding-issues-5.html on-line and it seemed to me some very knowledgeable people involved.

I would appreciate any help, maybe its best that I post all the details but doing this in the past on other forums has led to people complaining the post was too long and then no help because they dont want to read a long post.

With that said let me ask, is it possible that instead of my rear brakes working as they should that instead the fluid is just bypassing within the master cylinder like what it did when I bench bled it because the spring pressure or whatever was just stronger on the shoes?

I have a Frankenstein of parts on this vehicle which may seem complicated so that is why it would be a long post to name all the details. Thanks for your time
Make it very clear on the "the fluid is just bypassing within the the master cylinder like what it did when I bench bled it"

yes post ALL info on parts used and work you have done

btw , what are brakes ? your ready for a million page thread ? lol
 

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From what info you have given, sounds like your master cylinder is faulty. Output fluid pressure will overpower any brake spring holding the shoes together. Master cylinders are not designed to bypass if there is resistance.
 

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Discussion Starter #7 (Edited)
Sounds like spam to me. FOUR people signed in and made one post each yesterday....
I am sorry for my lack of response, I thought I would get an e-mail notification if anyone had replied, I did not so I assumed that no-one was interested.

I know this might not be exactly what you guys are interested in but please consider helping me, I am at the end of my rope with this truck.

Ok you wanted all the details. I will try and break this down easily

I have a 52 F-7 ford, this is a big truck, it was originally a fire tanker truck, it is not a semi, not nearly that big, F-11 maybe F-9 would be a semi but it is a big truck.

When I got the truck it was in pieces, most everything missing but 23000 original miles and as rust free as you could ever want.

I originally put a F-I 302 in it and also transferred some of the braking components I could get off the 1986 F-150 that the motor came from too include the master cylinder, power brake booster. That is all.

I ran all new lines, no residual valves, no proportioning valves, no nuthin.

I honed out the ( JUNK ) ( I thought they would be ok ) original wheel cylinders, 4 in the rear and 2 in the front. I did this because originals are un-obtainable and I did not have the 90 bucks per wheel cylinder to have them re-sleeved. I should have just saved my pennies and had them done.

The original set-up in the truck was master cylinder and brake booster under the cab, I had none of this, I didnt even have a pedal assy.

Believe it or not ( and I have pictures of everything ) the 1986 pedal assy is a nearly direct bolt in under the dash, just drill a few holes in the firewall and the pedals will reach perfectly fine from firewall to dash assy. This is what I did.

Ok fast forward I drove the truck, the 302 was a high mileage engine, much too small for the truck but it ran it down the road OK. I was having a problem stopping it though in that I would have to pump the pedal a few times to build up pressure. Once it was there no problem but let it go a few seconds and I had to re-pump.

The original master cyl ( 1952 ) had a bore size of 1 1/2 and a stroke of 1 7/16, this F-150 had a bore of 1.0 and I do not know the stroke.

Fast forward the motor was junk, I got tired of messing with the truck and just let it sit.

Sat for maybe 3-4 years.

I bought another truck that had a recently rebuilt 351 W and N.P 435 tranny. I decided to give it another go. I have the motor in it, just about everything is complete on the truck but now I am back with the brakes.

I threw away what I was working with, after 4 years of sitting it was junk anyway.

I decided to find the largest power brake booster and master cyl ass I could that would bolt onto my stock 198whatever pedal assy. This turned out to be a dual diaphragm booster from an F-350 over 8500 sumpthin or other and a master cylinder from an earlier F-350 that has a bore diam of 1 1/4 and a stroke of 2 inches

The master cyl would just barely not go onto the studs of the brake booster so I had to shave just a bit from the mounting ears but a 20 second job, fits like it belongs there otherwise.

I decided I would re-hone my wheel cylinders, no can do, they are junk. After searching on-line for years for replacements I just happen to find out the F-8 truck wheel cylinders would bolt right into my cage assy that holds them to the backing plate, F-8 rear wheel cylinders have a bore size of 1 3/4 F-7 original are 1 5/8 so these are 1/8 larger.

Front wheel cylinders on f-7 and F-8 are the same size at 1 1/4

I found out that the master cylinders for F-7 and F-8 originally were the same size at again 1 1/2.

I also did some studying and found out that I maybe needed residual valves placed as close to the master cylinder as I could so since the outlet ports on the master are 3/16 I came off the master with a 3/16 line into a 10 lb residual valve and then out the valve I opened the line up to 1/4 inch to the wheel cylinders. Can I attach a picture here?????

Guess maybe so


Here is a picture of the truck,
its not a piece of shiz but a very nice truck that I have hundreds if not thousands of hours into but too be honest I am almost ready to just give in. Where does it end, it has drained me of just about all my money at this point and I am at a loss.

Push the pedal down after bleeding the master and all the wheel cylinders and practically nothing will happen. It worked better before I up-graded with what I thought would be all the right stuff.

I have literally dumped 8 -10 pints of brake fluid in it trying to get a pedal, at one point I had a wheel locked up kinda but I could still move it with enough effort.

I can provide pictures of anything you guys need. I just dont know what to do!

Actually the truck looks better today than when that picture was taken 5 years ago. Same patina but I have finished alot of missing stuff
 

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Two things stand out to me.

1: Drop the brake line size to 3/16"

2: Make sure your pushrod rests without a gap on the MC plunger.

3: Properly adjust your front and rear brakes. You must have your shoes touching the drums. Adjust them out until the wheel don't turn, then back off 4 clicks on the adjusters.


You are using a SMALLER than original Volume MC, which is not going to put as much volume back to the rear wheels as the 1.5" master, so, will you get a larger volume per inch of travel with your pedal on 1/4" or on 3/16" brake lines?.

You need to make up for the volume of fluid going to the 4 wheels. The booster will help you all you need once that is done.

Glad you came back. Instant notifications must be turned on in your thread for that to work and sometimes it's not the greatest....
 

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Discussion Starter #9 (Edited)
Two things stand out to me.

1: Drop the brake line size to 3/16"

2: Make sure your pushrod rests without a gap on the MC plunger.

3: Properly adjust your front and rear brakes. You must have your shoes touching the drums. Adjust them out until the wheel don't turn, then back off 4 clicks on the adjusters.


You are using a SMALLER than original Volume MC, which is not going to put as much volume back to the rear wheels as the 1.5" master, so, will you get a larger volume per inch of travel with your pedal on 1/4" or on 3/16" brake lines?.

You need to make up for the volume of fluid going to the 4 wheels. The booster will help you all you need once that is done.

Glad you came back. Instant notifications must be turned on in your thread for that to work and sometimes it's not the greatest....
Thanks but I am confused on this ...........You are using a SMALLER than original Volume MC, which is not going to put as much volume back to the rear wheels as the 1.5" master, so, will you get a larger volume per inch of travel with your pedal on 1/4" or on 3/16" brake lines?.

Which is it 1/4 or 3/16, seems like more volume with the 1/4 but more pressure with the 3/16, I would think I need more volume.

Pushrod is touching master or damn close, hard to measure exact or maybe easy if you know a trick ?

Brakes have been adjusted.

I need to figure out how to pinpoint where the problem is exactly and start from there maybe ?
 

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By any chance, do you know the front and rear brake size (drum dia. X shoe width) and were any photos taken with the wheels off? You kept the original foundation brakes?

What size brake tubing was originally on the truck? Was it originally power assisted or manual?
 

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Trying To Narrow The Post Down To Basic Facts-

1952 F-7

1) When I got the truck it was in pieces, most everything missing

2) I originally put a F-I 302 in it and also transferred some of the braking components I could get off the 1986 F-150 that the motor came from too include the master cylinder, power brake booster. That is all.

3) I ran all new lines, no residual valves, no proportioning valves

4) I honed out the ( JUNK ) ( I thought they would be ok ) original wheel cylinders, 4 in the rear and 2 in the front. I did this because originals are un-obtainable and I did not have the 90 bucks per wheel cylinder to have them re-sleeved. I should have just saved my pennies and had them done.

5) The original set-up in the truck was master cylinder and brake booster under the cab, I had none of this, I didnt even have a pedal assy.

6) Believe it or not ( and I have pictures of everything ) the 1986 pedal assy is a nearly direct bolt in under the dash, just drill a few holes in the firewall and the pedals will reach perfectly fine from firewall to dash assy.

7) I drove the truck, the 302 was a high mileage engine, much too small for the truck but it ran it down the road OK. I was having a problem stopping it though in that I would have to pump the pedal a few times to build up pressure. Once it was there no problem but let it go a few seconds and I had to re-pump.

8) The original master cyl ( 1952 ) had a bore size of 1 1/2 and a stroke of 1 7/16, this F-150 had a bore of 1.0 and I do not know the stroke.


9) I bought another truck that had a recently rebuilt 351 W and N.P 435 tranny. I decided to give it another go. I have the motor in it, just about everything is complete on the truck but now I am back with the brakes.

10) I threw away what I was working with, after 4 years of sitting it was junk anyway.

11) I decided to find the largest power brake booster and master cyl ass I could that would bolt onto my stock 198whatever pedal assy. This turned out to be a dual diaphragm booster from an F-350 over 8500 sumpthin or other and a master cylinder from an earlier F-350 that has a bore diam of 1 1/4 and a stroke of 2 inches

12) I decided I would re-hone my wheel cylinders, no can do, they are junk. After searching on-line for years for replacements I just happen to find out the F-8 truck wheel cylinders would bolt right into my cage assy that holds them to the backing plate, F-8 rear wheel cylinders have a bore size of 1 3/4 F-7 original are 1 5/8 so these are 1/8 larger.

13) Front wheel cylinders on f-7 and F-8 are the same size at 1 1/4

14) I found out that the master cylinders for F-7 and F-8 originally were the same size at again 1 1/2.

15) I also did some studying and found out that I maybe needed residual valves placed as close to the master cylinder as I could so since the outlet ports on the master are 3/16 I came off the master with a 3/16 line into a 10 lb residual valve and then out the valve I opened the line up to 1/4 inch to the wheel cylinders. Can I attach a picture here?????


16) Push the pedal down after bleeding the master and all the wheel cylinders and practically nothing will happen. It worked better before I up-graded with what I thought would be all the right stuff.

17) I have literally dumped 8 -10 pints of brake fluid in it trying to get a pedal, at one point I had a wheel locked up kinda but I could still move it with enough effort.
 

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Where is the vacuum signal to the booster?

 

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Discussion Starter #14
By any chance, do you know the front and rear brake size (drum dia. X shoe width) and were any photos taken with the wheels off? You kept the original foundation brakes?

What size brake tubing was originally on the truck? Was it originally power assisted or manual?
16 inch front drums 15 inch rear drums I dont know i....wait
 

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Discussion Starter #16
By any chance, do you know the front and rear brake size (drum dia. X shoe width) and were any photos taken with the wheels off? You kept the original foundation brakes?

What size brake tubing was originally on the truck? Was it originally power assisted or manual?
I dont know the original brake line diam but I can find out, I have all the pictures you could ask for just ask

Yes original foundation brakes and yes vacuum assist
 

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Discussion Starter #18
By any chance, do you know the front and rear brake size (drum dia. X shoe width) and were any photos taken with the wheels off? You kept the original foundation brakes?

What size brake tubing was originally on the truck? Was it originally power assisted or manual?
Front brake assy,



Rear brake assy


Many more avail
 

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Discussion Starter #19
By any chance, do you know the front and rear brake size (drum dia. X shoe width) and were any photos taken with the wheels off? You kept the original foundation brakes?

What size brake tubing was originally on the truck? Was it originally power assisted or manual?
It sounds like you are able to do a math formula to tell me if this set-up is even possible to work, I am un-able to do that myself right now but I can provide the answers to any questions you may ask as long as they are avail to me.

I would like if you guys would ask me the appropriate questions needed to pinpoint the problem right from the beginning like I noticed some of you had done on another thread.

I believe if we did this than we could arrive at a solution.

Thanks for the help
 

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If you mean the vacuum line than it runs off the intake to the booster, you will see the fitting on booster if you look close enough maybe
Sorry, I meant the actual vacuum hose. When you road tested, was the booster operational?

I found your post(s) at FTE and understand your situation now.

My concern is the MC you have chosen. It is a light truck DISC/DRUM. I would think the larger reservoir (rear) would be better if plumbed to the rear shoes as they have dual wheel cylinders. Then the front to the front shoes. You need volume to actuate four wheel cylinders.

Having chosen the MC for safety I would think, the safety feature will not be available without a PRESSURE DIFFERENTIAL VALVE, but this can be done after you make the brakes operational.

If the truck originally had 1/4" line, it was meant to carry a larger fluid volume to initiate the rear wheel cylinders.

May I also suggest a POWER BLEEDER KIT to bench bleed the MC (see attached) (you can also make your own)?

I'll be back. CHOW CALL (the smoke alarm went off)...

OK... I added the MC bleeder.

As far as I am concerned, what you are doing is OK. The original setup was compressed air over hydraulic most likely. It would give more line pressure but if they came through with only a vacuum booster (notice dia) it should give about the same performance.
 
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