'66 brake rebuild

[Rosco1966f250]

I have inherited my dad's '66 F-250 camper special. This was the family truck my whole life- my dad recently wanted something w/ air conditioning and opted for a later model F 150. We have always had issues with the brakes. My dad has done some work on them. I fear we have a hodge podge part thing going on here.
I'd like to know what size bore on the wheel cylinders is correct. And, which model master cylinder is correct. I recently (about 4 years ago) had the master cylinder rebuilt by an outfit in Sacramento who I was referred to via Vintage Ford. They did a great job but mentioned they thought I had the wrong MC. Mine has a single line coming out of it and I remember the guy at the rebuild outfit saying he thought for the '66 it should have two!
There were times I remember when the truck wouldn't hardly stop ie. for my sister once while driving it through golden gate park. Almost totaled a row of parked cars. Other times they would lock up unexpectedly.
I've been reading about different size wheel cylinder bores causing exactly these symptoms. My dad is notoriously frugal and used to get all his parts from Kragen's. Perhaps the w/c are the wrong size?
I'd love to get the brakes sorted out once and for all. I don't have a shop manual. Could anybody weigh in?
thanks.

[1972hiboy]

Welcome to the forum!

That is neat having so much background with the pickup. I am no expert on the specifics for a 66' truck but im familiar enough to get you maybe pointed in a good direction. First off, whether the truck came with a single reservoir or dual originally , you should have a dual reservoir on the truck, for safety's sake.Your problems sound a bit multifaceted but here are some things to check. Individual wheel cylinders should not be stuck on either side, dry and all the same size bore per axle. Wether its the correct bore size for application isnt as important as having the same on both size, mix matching w/c's that way can give you a pull while braking. Have you taken the brakes apart for visual assessment? when was the last time the brake drums were machined? if its been decades, think about doing them with a new brake shoe set. the more they get a glaze on them over the years and wear, they tend to get uneven in areas,and the glaze makes them grabby. Flush the whole system with fresh brake fluid, brake fluid tends to collect water and copper from brake components and dilutes the fluid over time. Wheel bearing condition and oil/grease contamination on the brake shoes will both have a impact on stopping ability as well. I would say get the wheels off and take all four corners apart and check them out.

[Rosco1966f250]

Hello HiBoy,
Thanks for the response. Funny, though, I didn't see my post in the brake section...New to this forum, obviously.
Right now the truck is up on blocks and I was able (fortunately) to have all four drums turned. The braking system has been performing horribly recently which is why I got started on this track. After pulling the drums I noticed the front passenger wheel cylinder was leaking and then realized the M/C is super low on fluid. That explains the bad braking.
Parts are not readily available in my area and I am trying to figure out what size w/c I need. So, after looking online I found wheel cylinders with different bore sizes all listed for the '66 F250. So, while researching the effect of different bores size in relation to braking performance I found a lot of people posting in different forums about how the bore size can effect the braking performance- the general consensus seems to be that bigger bore=more force and more pedal play. As I mentioned, we have had a history of poor braking with the '66 and a lot of the problems seem to have the same symptoms as having the wrong size wheel cylinders- grabby or soft. I think maybe my dad at some point may have replaced one or two of the wheel cylinders with parts from Kragen's (O'reilly). Who knows what they offered him or how they determined which size was right.
My goal is to determine what is standard for '66 F250 Camper Special. I'd like to roll with the master cylinder that I have unless we can determine it is definitely the wrong part- it is a vacuum assisted unit. It says FoMoCo on it. It's old. Perhaps original.
IF anyone knows which master cylinder and wheel cylinder(s) go on this truck I'd love to hear about it.
Thanks HiBoy for your advice regarding the brake job. I'm planning to replace the shoes, springs, leaky wheel cylinder (all of them if I can obtain the info.) inner seals and axle seals and flush the system with new fluid.
Thanks for any follow-up.

[1972hiboy]

having a soaked brake shoe would produce grabby brakes for sure. glad your going through them, sounds like they are due. The wheel cylinder bore dimensions are going to be in reference with gvwr ratings, so it should prompt the parts person to start asking about gvwr ratings if their are options for wheel cylinders. The single reservoir is most likely correct for the application but it would make me nervous using it ( that's just an opinion). The whole idea behind the dual reservoir master cylinder that came out the very next year is to split the brakes into two systems instead of one. So if a problem arises in one system the other still functions enough to stop the truck. In the single reservoir system, if a wheel cylinder blows or a soft line ruptures, that brake pedal is going to go to the floor and stay there.But i understand restoration preference,or wanting to keep things stock. I would make sure my hand brake was in very good working order. I went around back and forth a few times before I decided to split the hydraulic system in my 48' sedan. In the beginning i refused to give up my old Lockeed casting 'made in usa' single res. I have it around now just in case ever want to put it back on.

[390FE1972]

Just to let you know incase you aren't aware of it, there is a web site for 1961 to 1966 trucks called Slick 60's. It might help you with other info in fixing your vehicle up. http://www.slick60s.com/

Regards

[Rosco1966f250]

Rich, The e-brake on our'66 is a junk show. The column shifter slips out of park all the time and instead of just setting the e-brake I use a bungie to hold it in park. You could blow a disc pulling on that thing and then only barely have any hold. Pretty useless. I wouldn't know how to make that spring action any easier without doing some kind of full on redesign/build for that. I don't have the time at the moment for that kind of project. I think in an emergency with Mr. Adrenaline running I would be able to pull the ebrake enough to slow us down. I like keeping things stock so will roll with the single port m/c for now- maybe I'll have a light bulb moment and upgrade to an aftermarket dual port sometime. Maybe that moment will come sooner than later as we live up a very steep hill...I'm thinking that replacing all the shoes and wheel cylinders, etc. and turning the drums should buy me some brake system security for a while at least.
Thanks for the advice on sizing the wheel cylinders. I will talk to my local parts supplier and see what he thinks. Not sure if he's sophisticated enough to know which size vs. GVWR would be the best fit but I can check with a couple of places. I was hoping for spec. on the wheel cylinders and master cylinder from someone who has the '66 shop manual.
And, I will check out the slick60's website. Thanks for the suggestion (390FE1972)

[sargentrs]

I recently had a '64 Fairlane with the single m/c. Never had a braking problem in the almost 3 years I drove it, daily, 80+ miles/day. With that said, I jumped over to Slick60s and did a quick search. Came across this dual master conversion thread. I would definitely do this. http://www.slick60s.com/viewtopic.php?f ... er#p316190

[Rosco1966f250]

10-4 Randy! I've been scouring the slick60's site. I'll follow up with the dual port conversion thread . Good to know you had success with the single port however. '
With that said, I believe the bore on the front w/c's is 15/16 while the rears are 1 1/16. I'm going to go with that and my original master cylinder for now.