It's a 1.5" bore master dual piston cylinder in the rear and disks up front. Pedal stroke is short so smaller bore would work OK. Can't see it in the picture but there is a clutch master cylinder left of the hydroboost. one of the reasons I rotated it.

 

Thanks for that picture and description!

There's no clutch for mine! (auto-trans) and without the other pedal and shortened pedal pivot shaft I think it will fit in there with the much larger E4OD transmission.

I have been worried about the amount of fluid required for the double cylinder (4-total) rear brakes and the single cylinder single piston front brakes.

I see the adjustable proportioning valve you have too. can you post the model number and source?

I also may not have power steering. so how you did the power steering pressure line would help too. Did you just "dump" it directly into the return or is there an orifice in the line so it produces *some* pressure?

I have a lift gate for the back so I am tempted to run some steel lines to the back to operate it instead of using the battery powered hydraulic "pack"!

Finally, did you use a residual pressure (check) valve? I got the impression that it could be required in an all drum system.....

 

Used the Wilwood 260-11179 with built in pressure switch for lights. The high pressure line is run back to the tank with no orifice. Works fine that way.
Running that back to a liftgate should work OK.

 

Thanks for that!!

For all the rest of us, I also found some info on recommended residual check valves.

Tech Support

Here's some more sources for proportioning and check valves.
http://www.powerbrakeservice.net/99fof2f3f4an.html

Cheers,

Rick

 

Stephen67,
I installed a hydroboost system in my 48 F1. Industrial Chassis in Phoenix did the work. Here is the link to my build thread. Post #14 is the hydroboost installation.

https://www.ford-trucks.com/forums/1...ld-thread.html

In that same thread, petemcl suggested the use of an electric vacuum pump at Post #17. That could be another alternative.

My hydroboost is under the floor on the outside of the frame rail. Since the location of the mount coincided with the body mount, Industrial Chassis ended up making a custom mount for both the hydroboost and the body mount. The pictures and drawing show the work needed to install mine. The brake pedal was located in the original location.

Philip

 

Howdy Philip, not to hyjak, but do you AV8 in AZ? (Did I already ask you this?)


Cheers,

Rick

 

Rick,
To explain my name on multiple forums, AZAV8, I am NOT an "aviator" as in flying aeroplanes. The "AV8" is an old hot rod term for a Model A Ford with a flathead V8 engine. That was my original project car when I registered on the H.A.M.B. at The Jalopy Journal. Since "AV8" was already taken I added AZ to the front because I am from Arizona, thus "AZAV8". I have used it on all of the forums, on which I am registered, including here. You can find me at many forums, The Ford Barn, The Garage Journal, here, the H.A.M.B., and others that have slipped my over 40 memory which is frequently struck stupid with C. R. S.

I am currently working on a 1948 F-1 pickup which is a "hot rod" because I can't imagine building something stock, because they ride like trucks and are horribly under powered.

Philip

 

Something tells me we have had this discussion before

 

Lot of good info here. Lot of stuff I didn't realize I needed to do.

I like your solution Philip of having it on the other side of the frame. Whole lot going on in that little area between the frame and transmission, be nice to free up a little space. The booster I got isn't exactly a small guy.


Anyone know how much travel the pedal will need to produce? I'd like to get it where it's resting lower in the cab but still able to give 100% (and have no clearance issues with the carpet or something). Right now the pedal sits a few inches higher than ideal.

 

Stephen,

I did some preliminary measuring today.

The original MC has a maximum piston travel of 1.875" and a piston diameter of 1.375" (radius is diameter divided by 2)

Using Volume = Piston Area (A) x stroke..............and π (pi)= 3.1416



Piston Area A = πr2

Pi x radius (squared)

The piston radius= 1.375" divided by 2 ===> 0.6875"

So................ 3.1416(pi) x 0.6875 (squared) ===> 1.485 sq-in

The total volume of the cyl is piston area x stroke......... or, 1.485 x 1.875 ===> 2.784 CU-in

This is the amount of fluid you would get if you put the brake "pedal to the metal" (1.875" MC piston movement) and (in the original MC) this fluid is used to operate the 4 back and 2 front wheel cylinders.
Since you don't usually (ever) use full stroke (pedal to the floor) , the actual fluid required is much less

---------------------------------------------------

For the newer hydro-boosted double piston (split) master cylinder, I measured 1 3/8" piston travel and it has (2) 1.5" pistons (one for the front brakes and one for the back)

Piston radius is 1.5 divided by 2 ====> 0.75" .......

So volume is 3.1416 (pi) x 0.75" (squared.......) x 1.375" (stroke)

or ======> 1.767 sq-in x 1.375" ===> 2.43 cu-in (ea.....front and BACK)

Both systems are capable of providing 2.42 cu-in (each) in the FRONT and 2.42 cu-in in the back system


This should mean that the piston travel will be LESS than what was required if you used the original MC supplying BOTH front and back brakes......

However, it's possible that the front piston will provide much more fluid than necessary and will need a proportioning valve to compensate.

I set the booster and MC in the frame approx where it will go and snapped a couple of pictures....
Looking from front to back down the left side of the engine.

The front of the booster is sitting on the trans cross member. I'll be welding a plate to the cross member so I can bolt it directly to the trans mount.

Looks like I'll need a 12-15" rod from the pedal actuator to the booster.



This is going to be easier than I thought!

 

Nice, just what I needed to know to figure this out.

Though I must say I wish I had my cab off like yours, I spent hours yesterday just trying to remove some rusted out pins on the brake assembly, ha.

I'd like to continue to see your progress on it.

 

I haven't done a LOT of work on it in the last 5 years or so. Now that I am getting ready to retire, I am going to start fooling around with it again!

The cab is off so I can finish the frame work to include getting it blasted. Then, I need to replace the cab-corners and get it blasted as well as the other sheet metal.

The transmission being quite a bit longer than the original T-98, (I still have btw if someone up here in the NW wants it!!) required me to shorten the front drive-shaft (done by NW Driveline in Tacoma)

I also had the radiator re-cored by a rad shop in Tacoma. They removed the 3-row core and installed a 4-row core in the original style!

I am debating installing an OEM hydraulic assisted steering (as opposed to a regular PS box) THe original power steering is like F/E-250/350's in the 60's and 70's using a steering "valve" in the pitman arm drag-link...

I don't think those drive as nice and have the "feel" of a standard power steering box but I am not having a great time finding a (hyd) steering box that would fit where the original is.

If I use an original steering column(Auto-trans....still looking for one.....) and that big steering wheel, it's not all that bad to drive with manual steering!!

 

I have the lever for an automatic off a '56 car. It's about 6" shorter than a truck one, but that's an easy fix since it's just a tube you have to add some length to. There is also an indexing plate for the lever to lock into to keep from bumping into reverse or park.

I was hoping to get most of it done today but my steering wheel proved to be more stuck than any wheel has the right to be, lol. If I find a full column I'll let you know, they seem hard to come by, hence why I'm making one.


I do like you're idea of setting the brake booster back a little bit. Might allow room for a linkage rod that can be adjusted for my brake height problem. (I'd like it to be lower). It would need some design work though so it doesn't twist but shouldn't be hard to get it to work well.

 

In reality, you could put the booster/MC well back & behind the cab if you wanted to. You would just have to provide enough support for the "push" rod so it didn't flex or bend when you "mashed" on the brake! I just want it in a place where I can get to the reservoir cap easily

It would really be nice to find an original F-100/250 auto steering column but I am not optimistic. I suspect they're out there......many people don't seem to want an automatic in their vintage trucks, especially F250/350 and medium duty trucks! I wanted my automatic for the tail-mounted parking brake .....it came out of an F-450 SD so I suppose it's certainly "heavy" enough for an F600 even if I load it up to MGVW

If I had gone with a different (more modern) engine, I probably would have gotten a 5 or 6 speed ZF (with the tail mounted P-brake)

My second choice was going to be a newer EFI 300-6 + ZFS-5 out of a newer F-250/350.......but, I really like the sound of a Y-block though.

 

Welded up the mount for the booster today!