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66 f100 master cylinder
Posted: June 20, 2013, 7:10 am
by Baer
The master cyl on my trick is an oval one with the small cast iron cap on it. Everything I have seen says it is suppose to be the round one with the big screw on cap. Which way do I need to go?
Thanks
Re: 66 f100 master cylinder
Posted: June 20, 2013, 8:28 am
by unibody madness
I would replace it with a dual master cyl, check and replace brake lines, at the least the rubber hoses that may look ok but are goobered up on the inside
Re: 66 f100 master cylinder
Posted: June 20, 2013, 5:33 pm
by Baer
I am wanting to stay pretty much stock. I am gonna check all the brake lines. Was just wanting someone's opinion on which one they thought was stock.
Re: 66 f100 master cylinder
Posted: June 21, 2013, 7:04 am
by bruceandersson
Everyone I've seen has been round with the screw on top.
Re: 66 f100 master cylinder
Posted: June 21, 2013, 8:53 am
by f100jim
Original master cyl. I added booster.

Re: 66 f100 master cylinder
Posted: June 22, 2013, 6:08 am
by DV65CustomCab
Jim, which booster did you use? I want to shop at the "auto reclamation facility" for one.
Re: 66 f100 master cylinder
Posted: June 22, 2013, 8:29 am
by BarnieTrk
Baer wrote:I am wanting to stay pretty much stock.
You might want to reconsider this decision - consider these comments from another thread:
"Reason #1 to ditch the single pot m/c's on these trucks.
Originality be damned; it you can't stop the thing, no one will care how original it is.
When it's in a smashed heap, all that will be said is, "Dang, what a shame too, 'cause that WAS a cool ol' truck!"
BarnieTrk

Re: 66 f100 master cylinder
Posted: June 22, 2013, 9:00 am
by unibody madness
Baer,
The one pictured above is all I have seen on original set ups.
I also agree with barnietruck,Here is the link
http://slick60s.com/viewtopic.php?f=1&t ... 5customcab
I also had a brake issue allthough not as dangerous, and am converting all my trucks to the
dual pot. I am using the vac assist where I can, because I drive different makes and models of cars at work, and at home, so the vac assist helps with the feel between vehicles.
A free running 5000 lb. vehicle is no joke at one mile per hour, much less 55.
John
Re: 66 f100 master cylinder
Posted: June 22, 2013, 11:07 am
by ICEMAN6166
BarnieTrk wrote:Baer wrote:I am wanting to stay pretty much stock.
You might want to reconsider this decision - consider these comments from another thread:
"Reason #1 to ditch the single pot m/c's on these trucks.
Originality be damned; it you can't stop the thing, no one will care how original it is.
When it's in a smashed heap, all that will be said is, "Dang, what a shame too, 'cause that WAS a cool ol' truck!"
BarnieTrk

i like stock too.
i run drum brakes and points ignition.
still i have converted to the dual m.c. for reason #1 posted above.
if you do nothing else to your truck this one thing is well worth the minor amount of time and $ to do.
Re: 66 f100 master cylinder
Posted: June 22, 2013, 3:49 pm
by f100jim
DV65CustomCab wrote:Jim, which booster did you use? I want to shop at the "auto reclamation facility" for one.
I got it at Advance auto parts for a 68 f100. Had to shorten the brake pedal push rod and adjust the front rod a little for the MC. Don't remember the part no,sorry.Most I'd find at the junkyard were well, junk, but you might get lucky.
Re: 66 f100 master cylinder
Posted: June 22, 2013, 4:21 pm
by MadMaxetc
Just an FYI guys:
When I took off the rubber lines on my 63, they had absorbed so much water that there was barely a pin hole for the fluid to pass through.
If you are do this much work, replace the rubber lines!
Re: 66 f100 master cylinder
Posted: June 22, 2013, 8:26 pm
by BarnieTrk
MadMaxetc wrote:Just an FYI guys:
When I took off the rubber lines on my 63, they had absorbed so much water that there was barely a pin hole for the fluid to pass through.
If you are do this much work, replace the rubber lines!
I have also had the inner lining of more than one brake flex lines give me fits...... in the end they would act as if all of a sudden they had a check valve (fluid would only travel to the wheel cylinder, but would not go back to the MC). I would have to back off the 'star adjuster' to get the drum off only to find the piston pushing the shoes out. I changed the flex line and all was well again..........I never did determine just what or why the internals of the flex lines broke down....... crazy.
BarnieTrk

Re: 66 f100 master cylinder
Posted: June 24, 2013, 5:41 am
by DV65CustomCab
MadMaxetc wrote:Just an FYI guys:
When I took off the rubber lines on my 63, they had absorbed so much water that there was barely a pin hole for the fluid to pass through.
If you are do this much work, replace the rubber lines!
Yep, I've lived that too. When I bought Big Red, I thought "I know the brakes on these aren't spectacular, but these really suck!". When I got to poking around at it once it was home, I found that the front hoses were completely swollen shut; the only functioning brakes I had were on the rear wheels!

These don't get replaced often enough; you can see wheel cylinder leaks, and you can see cracking on the outside of dry rotted hoses, but you can't see the internal swelling. Replace them any time you do a major brake repair. They aren't that expensive.
Oh, and flush your fluid regularly, something even I haven't done as often as I should.
Re: 66 f100 master cylinder
Posted: June 24, 2013, 12:17 pm
by BarnieTrk
DV65CustomCab wrote:........ I found that the front hoses were completely swollen shut; the only functioning brakes I had were on the rear wheels!

These don't get replaced often enough; you can see wheel cylinder leaks, and you can see cracking on the outside of dry rotted hoses, but you can't see the internal swelling. Replace them any time you do a major brake repair. They aren't that expensive.
Oh, and flush your fluid regularly.......
YEP! 2X ^^^ -- BarnieTrk
Re: 66 f100 master cylinder
Posted: June 25, 2013, 11:23 pm
by cdherman
I have had a single chamber brake cylinder fail on me once -- as a teenager backing out of a drive and my buddy hollers "Hey there's a semi coming".
So I hit the brakes hard -- and got the most sickening feeling in my stomach as the brake pedal went to the floor and the car just continued down the driveway, intent on getting in front of the 16 wheeler.
Got lucky, he braked and my 17 y/o brain decided to floor it and shoot across the highway and into the ditch on the other side.
Get rid of single cylinder brakes........
Re: 66 f100 master cylinder
Posted: June 26, 2013, 5:50 am
by Toyz
Absolutely one of the best ways to improve safety on any vehicle! Well, other than leave them parked as I do
At an early age, I found the value of what was often referred to as an emergency brake when a rear shock mount broke, resulting in a severed brake line. Trust me, the combination of two rear wheel mechanical brakes and the oh, s...! time before applying, leaves plenty to be desired!
Paul
Re: 66 f100 master cylinder
Posted: June 26, 2013, 7:56 am
by BarnieTrk
Toyz wrote:.... I found the value of what was often referred to as an emergency brake when a rear shock mount broke, resulting in a severed brake line. Trust me, the combination of two rear wheel mechanical brakes and the oh, s...! time before applying, leaves plenty to be desired!
Paul
Paul,
That brings out an excellent reason why a fella should ensure the emergency brakes are useable. They aren't just for parking on an incline............. they can also serve a purpose in an EMERGENCY!
BarnieTrk
