Technical OK, What do I do now?

I'm sure that this has been covered somewhere but I'm only on my second cup of coffee and what's left of my brain hasn't kicked in yet. Master cylinder is where it has to be, the T-fitting is installed with the correct crush washers and the brake light switch is in the right place. The question is, where do I put the 10# residual valve? Do I plug one side of the T, add the valve to the other side and T off of the valve or am I making this harder than it has to be?

 

They usually go inside the master cylinder, as part of the master cylinder.

 

If you are doing it that way, with one residual valve for the whole car, couldn't you use a single sided fitting instead of a double sided fitting? Then you have one less place to possibly leak.

 

um, if running two lines, buy 2 valves if running one line, buy 1 valve and 1 block off.

 

re post 1 : I doubt whether there is one inside that style of master cylinder.
re post 2 : this is good advice, - or as you suggest, plug one outlet.

Personally, I have a similar or same master cylinder and the same tee fitting, and one line goes to front brakes and one to the rear. Drum brakes and no residual valves.
After having several of those hydraulic brake pressure fittings fail every year or two, I threw it out and went with a mechanical brake light switch.
A lot of information on here about them, - general consensus was only the HD ( Harley Davidson ? ) one was reliable.

 

First I would check up whether the M/C has built in residual valve. If it has take 1 pipe off of the fitting in the picture to the rear and 1 pipe to the front. If it has not do as " alchemy " says put a two way fitting in the M/C take 1 pipe to the R/V then put a 2 way fitting on the other side of the R/V. I would also make up a bracket to hold the R/V firmly.

 

Thanks to everyone, @brading, @clem, @millersgarage, @alchemy and @Rusty O'Toole who posted. I doubt seriously that stock 1948 Ford master cylinders had a built in residual valve and I wasn't sure what I'd run into running a valve on both the front and back lines.

 

I probably missed something in all this, but on my 40 chevy my MC is under the floor. My resid valve is an inline version, forget who i got it from, but just put it inline anywhere you want on the brake line. I bought some 6" lines with the flares/fittings and plumbed it up, easy.

 

I thought all drum brake cars before 1976 had a residual pressure valve in the master cylinder. It was necessary to keep a little pressure on the wheel cylinder cups to prevent leakage. This would not do for disc brakes as it would prevent the brake from retracting.
1976 up Chrysler products had a new type wheel cylinder that did not need residual pressure. I don't know if other cars had this feature.

In this illustration you can see the residual pressure valve 2178. It goes in the end of the master cylinder.


Here is what one looks like. It is the silver dingus with the 6 holes, below the black rubber boot.

 

Dingus! I love when people talk technical!

 

If you have springs in your wheel cylinders do you even need a pressure valve? If no springs then use a valve.

 

Those masters have the valve inside them already if its a stock type replacement. I have installed 3 of them this week at work and they work fine right out of the box .

 

An old friend used the term Dingus, all the time. He told about welding overhead, and didn't have his shirt buttoned all the way up. Well, a dingleberry, went down his shirt, and traveled down, burning him all the way. He was dancing around, adjusting his clothes, and it wound up in his shorts, burning the head of his Dingus !

 

OK, thanks. I'll try your way first. When I first started this, I was having a hard time believing that a brand new Chinese master cylinder from NAPA would have the valve already in it.

 

If it was a under floor mounted master cylinder from the get go you shouldn't have an issue as it will have that residual aka Check valve in it. I've never had a single piston master cylinder apart that didn't have one either under floor or firewall mounted.

 

That was the change they made in 1976, springs to hold the cups tight against the cylinder.

 

Well, that explains everything!

 

thank you.- I have learned something today !
Would the originals have had a residual valve in them ?

 

Put that sucker together Alan, bleed it all out and get you a good pedal. If you come out the next day and the pedal hits the floor for the first few pumps, do like was said up there above and get you a couple of 6" lines to come out of the master and into the rpv's, yeah I'd run one on each line, you can't run one between the master and the T because your brake lights will stay on

 

yes they did. The easiest way to check in to poke a toothpick into the outlet of the master cylinder. It will stop at the residual valve. If it doesn't stop there is no valve.

 

" enjenjo " That another good and simple idea that I will have to make a note of.