[HOW TO] Dual master conversion & booster rebuild

[burnski]

So I decided on advice of this forum to ditch the single master cylinder and replace it with a dual master cylinder for extra safety. Instructions borrowed partially from here: http://www.thelincolnforum.net/phpbb3/v ... f=4&t=3528

Parts for dual master conversion:
Master cylinder: Dorman Master Cylinders M71245
Two copper-nickel brake lines 3/16. one 8", one 12" length.
inverted flare Plug fitting (Weatherhead part number 131x3)
Brass brake T fitting (two 3/16Ã inverted flare, one 1/8 pipe thread) (Weatherhead part number 652x3)
Brass brake line adapter (9/16-18 male thread, 3/16 inverted flare female (Weatherhead part number 7911)
O-ring for new dual master snout to seal against boster(I used 36mm ID, remember the cross-sectional diameter)
New nuts & lock washers, 2 each 3/8-16.
Brake fluid.

Installation instructions:
- Bench bled new master per instruction sheet.
- Remove old master cylinder.
- Pull pushrod out of brake booster, remove the acorn nut from end. shorten rod so that overall length (with acorn reinstalled) is to 3-11/32"
- Replace pushrod into booster.
- install O-ring around snout of master cylinder to create vacuum seal against brake booster.
- install new master cylinder and attaching nuts/washers. (NOTE: Make sure to install the O-ring on external neck of master cylinder. Without it, you will have a vacuum leak, and poor power assist)

- disconnect the factory steel brake line that went from the factory master down to the factory junction block that is attached on the fender.
- Disconnect the front brake steel line from the fenderwell junction block leaving only the brake line to the rear brakes attached to the factory junction block.
- Install plug fitting (Weatherhead 131x3) in the junction block to fill one of the open holes created in steps above.
- Bend 12" length 3/16 brake line to connect from front brakes outlet (which is for rear brakes) on new dual master cylinder to existing junction block on fenderwell, filling the third outlet on the factory junction block.

- Install brake line adapter fitting (WH #7911) in the rear brake outlet on master cylinder (this if for front brakes).
- bend the disconnected existing front brake line from the factory junction block up so that it is accessible, and connect it into the Tee fitting (Weatherhead 652x3).
- bend 8" length 3/16 brake line to go from other inverted end flare of this tee and connect to the reduced that you just installed in the rear port of the master cylinder.
- install brake sensor into NPT end of the tee. use teflon tape. reconnect brake light wires.
- Filled master, bled brakes (front and rear)

i pulled to old single master off and found my booster was filled with fluid, likely caused by the old master leaking out the back and into the booster.

only solution is to pull the booster, tear it down, and hope its rebuildable, however i kept hearing that pulling the booster - especially from the 64-65 was extremely difficult. i pulled the car into the garage, pulled the seat all the way back, got as close to the wall as possible so i can put my feet on the wall for leverage. As far as "can i do this?" well im 35 years old, 5'8", 240lbs, not exactly the definition of "fit" but im determined as hell. you decide if you can fit.

first thing i did was remove some insulation and the neutral safety switch [NSS], and some wires/hoses/cables that were hanging down, look up and there are the first two nuts that need to be removed. for tools, i just used a 3/8" drive 9/16 deep socket on a wobble, as well as a 6" & 12" extension. spun both nuts off from under the dash no problem. i used a magnetic reaching tool to retrieve the washers.

then i slide myself up a few inches, and can easily see the other three nuts. again, same tools, spun those off.

for the C-clip to the brake pedal, i just grabbed on with needle nose pliers, gave it a tap and it popped off. then i grabbed the master from under the hood, gave it a jiggle, came right out. had to swing one of the cross braces over to get the booster out.

i have the booster sitting on my bench, soaking the screws holding the halves together with MoovIt. hopefully its rebuildable. Also while im in here with the master/booster out of the way, its a good time to do the steering box bushings, lower shift tube bushing, and rag joint.

Here's the booster in the vise, trying to get the stubborn bolts out. they are just slot head so of course on one the driver slipped out and i smashed my hand. managed so far to get 5 of the bolts out. hopefully a bit more soaking that last 3 will give up their grip.

any questions let me know!


EDIT

i also got the brake booster torn down. i think a good cleaning and replace the felt & leather gaskets as well as a few orings ill be back in business. no deadly springs or anything of the sort to be worried about. pretty simple actually.

EDIT 2 make sure you follow the procedure in the manual for resetting the neutral safety switch when you reinstall it


EDIT 3 i replaced all the vacuum hose in the power brakes system. I have a manual vacuum pump but there is a ton of air in the brakes and would be squeezing for a hour to get all the air out. I Jerry rigged an electric tire pump to use the inlet as a vacuum. T'd in the manual pump to get a vac gauge.

Pumped the system up to about 18inHG (pump tops out). Let it sit for like ten min, then press the brakes. Silky smooth, get about 3 brake pumps until it uses up all the vacuum. Job done!

[Dan Szwarc]

Clean it out and cross your fingers.


However, fluid in the booster may compromise the rubber diaphragm inside and that means your car can get pregnant.

[burnski]

Yay! A mini Lincoln. Would that be like a Ford Fiesta?

I'll pull the booster, clean it. Is there like a seal kit that can be bought for it?

[Steve K]

Once you have gone through getting that booster out, I seriously doubt you are going to want to put it back in and just hope for the best knowing you might have to repeat that procedure. But whatever you do, don't button it all back up at least until you know it is working. It is one RPITA to get that booster out of there.

And I will ask a favor on behalf of a lot of us less talented DIYers out here. If you do pull the booster PLEASE photo document the procedure. I know of at least three of us having a really hard time getting ours out and on their way to Booster Dewey. You have such great photos documenting your work that you would do this forum a great service building a thread on this procedure. There isn't one that I can find that outlines how to do it and the shop manual is very limited in the instructions.

[burnski]

Consider it done.

[Solid]

Burnksi, mine was full of goo like that too. It was done. You'll see that the nuts that secure it to the firewall from inside the car are in one case very difficult to get a tool onto. Best approaches may vary from year to year and I don't know '64, but I went through the speedo opening taking it out because it was a nice straight shot. That wasn't a good return path because it was hard to load the nut into a socket and thread it through all the wiring harnesses, so I used a socket on a universal with a 2 foot 1/4" extension to sort of limp wrist the nut back into place from beneath when I was reassembling. IIRC, I got it started that way then had to switch to a deep well on the same universal and super long extension to get the nut all the way secured.

One other sticking point which may or may not be relevant, the booster studs and interior nuts sandwich a couple pieces of metal to the firewall, including the steering column brackets. When I removed the booster on my '62, one of those pieces shifted just slightly so I couldn't get the studs back through. I ended up using a die grinder to slightly enlarge the part of the hole on the shifted bracket that was visible through the firewall from the engine compartment.

[burnski]

So thinking outside the box here. All 8 of the screws that hold the halves of the booster together are accessible from the engine bay. Can I just split the halves and leave the one half I the firewall to do the rebuild?

Found a rebuild kit: http://www.ebay.com/itm/172076546861

[Steve K]

Wow, well if that works, that would be worth documenting also!!!!!!!!!!!! That would save a ton of grief. I wonder if Booster Dewey rebuilds just half the booster All kidding aside, because I am a "senior citizen" and am somewhat disabled pending back surgery, any information to make this go easier or more surely would be vastly appreciated. I guess I gotta assume taking it apart as you suggest doesn't work or it would have been discussed here before but, that said, everything is done or written down for the first time once.

[burnski]

Reading through the service manual, the rebuild seems pretty easy... Easy enough it could be done with half still on the firewall.. I'll explore it a bit more as a plan b incase I can't get the booster out.

[Steve K]

The long and the short of the whole issue seems to be:

You can get it out but it's a pain in the ass to do.

I have an added concern and that is my preference to do "minimally invasive" approaches (to use the language we use in the medical field). The less I have to dig into the internals of the car, the less likely I am to disrupt old but working items such as wiring, vacuum hoses and instrumets. For me the idea of digging around blindly by braile under the dash or removing the speedometer to do this creates a high likelihood of not getting everything back together in the same working condition it came apart. I know that sounds a little silly but if you can't see what you are doing it's a fairly high possibility. Add to that that the fasteners and dashboard components are aged, dry, and brittle but are cosmetically excellent means its easy to damage one thing while fixing another.

All that just means the more details available when taking on the job, the better I feel about taking it on. I probably shouldn't be so sentimental as it's just a car. I am just particularly attached to this particular one because of my past association with it.

[TonyC]

I had heard that it is very risky to take the booster apart; there is supposed to be a large spring in there that can cause a world of hurt if you aren't careful.

I found it easier to have Booster Dewey take that risk, since he has all the equipment needed to keep all his fingers.

---Tony

[burnski]

thanks Tony, im not too worried about that. the full rebuild instructions are in the service manual - ill just wrap a strap around it when i take it apart just incase it trys to spring itself apart once i remove the screws.

[burnski]

alright, doing some reading. best I can tell my booster still works, its just full of fluid. im hoping i can pull it, clean it up, and reinstall it.

is there any reasonable way to bench test a booster or do i pretty much need to reinstall it and hook it up?

[burnski]

Booster is out. Took like twenty min, didn't pull the dash or anything... Not sure why everyone keeps saying this is so hard to do. I'll post pics later.

[Solid]

Cool. Do the studs on the booster go through the steering column support bracket in 64?