I'm planning on adding 1970 front discs to my 65. This will require a dual Disc/Drum master along with some new plumbing. In thinking about the plumbing of the lines, I see a way it could be perhaps made easier.
The existing single master 4 port distribution "T" could be made to work...If I could block the port currently used for the rear line. I'd like to keep the existing front lines intact leading from the block, feed in from the top port and block the rear.
Is there such a thing as a tube nut "plug" that can be used to block a port? I know it likely must seat onto the existing seat in the block somehow. But would a small brass NPT pipe plug work?
I know they make 3 way brass flare Tees, but I'd like to use what I have in place. The stock lines appear to be intact and in near perfect shape.
Thanks, Mark
Looking for a fitting to block off the rear line port (line with the guard wrap).
Yes, they make brass flare nut plugs. I saw my first one a couple years ago, and grabbed some that would be for plugging the tranny cooler lines in a radiator.
Yes, Weatherhead for sure makes them and I think Fairview does too, I've bought them also. If you can't get a parts guy who can figure it out, let me know and I can get you part numbers.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
I did this brake conversion and used the plug you seek to block one side. I utilized the original "T" block that you show but had issues with uneven pressure to the front, specifically the left always had more pressure causing a pull. After countless hours and replacing parts etc,I determined that it was the original "T" causing the issue. Depending on which way it faced, there was better flow thru to one side over the other, but not sure why.
I suggest replacing it with a block that has only the number of ports needed - no plugs, and with as few right angles as possible.
Good to know. Thanks Steve, could be a big troublesaver!
One possible solution could be to simply turn the block 90 degrees?
Block the old outlet that originally went to the right wheel (red dot). Use the two outlets (green dots) to feed the front. The green dot to the left would be originally the rear brake outlet.
Might it be better balanced? Feed straight down from the top, and distribute out the same distance right and left.
Are the front brake lines on a disc car the same size as drum? I used to know this.
Did you do any front hold off valve or rear proportioning valve Steve? This is a 70 setup, and would have had the front hold off valve at the master, which I have.
-- Edited by cdnpont on Sunday 12th of April 2020 08:33:03 PM
I have put the OEM 69-70 single piston setups on two of my cars, and am using the original OEM setup for the four piston units in my 68 Impala, which use the same master cylinder and hold off valve as the single piston units.
Mine work perfectly with that hold off valve setup, so I would recommend it. You can now buy a repro hold off valve from a few suppliers, and John Stuart Limited in Stony Creek, ON can also rebuild them.
One other thing to note: you will need the original style Tee with its deeper inlet for anywhere that the hydraulic hose enters the fitting. The typical brass parts store piece is too shallow.
This was an ongoing headache for me that took forever to solve. I literally replaced every part from the master to the hubs multiple times, even the proportioning valve thinking I missed something..... still kept pulling to the left, no change.
Then, like an epiphany, I decided to examine that little distribution block above the left wheel (still an original part) and discovered that the flow differed from port to port even tho there was no visible issue. After swapping it out, cured about 95% of the issue. So still some problems but believe it to be a matter of sticking caliper guides and other little things.
One other note you may find helpful: I also learned that the push rod inside the booster was not fully retracting due to slight maladjustment causing a bit of drag on the calipers, naturally the left more than the right and particularly when hot. Apparently this slack adjustment is commonly overlooked. Noticed immediately that it rolls easier.
Thanks Steve. Absolutely the pushrod length is critical. Been there as well.
Hard to believe the flow through that block would even matter under braking pressure, but there you have it. Brakes and their accompanying hydraulics can be fickle.
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65 Laurentian post, 67 Grande Parisienne 4 door HT.
Haven't gone out and got the plug yet Carl. The original idea was to use the original and perfectly intact brake lines.
That might all change, as I think the disc brake flex hoses inlet might use a larger tube nut and line (1/4"). So the whole thing might be redone including the T.
I'll wait see when the flexlines arrive as to the size.
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65 Laurentian post, 67 Grande Parisienne 4 door HT.
Ok, I took Steve's great advice about the original T causing flow issues when blocking the old rear line outlet. Makes sense to me, in fact I blew through the fitting when blocking each port, and sure enough the flow really (sounded) better and even through each green port shown as compared to the red port, that old front right port. In my mind symmetrical is better than asymmetrical for flow, but I never thought hydraulic pressure would care or even be be affected by a flow path.
So I figured I'd turn the port and bracket 90 degrees on the frame, and use the greens to feed the fronts. Block the red (originally the right front).
My question is, now that I'm feeding from what was originally a 1/4 and a 3/16 line from the T, both always being a 3/8 - 24 fitting. Will I still seal a 3/16 line on what was originally a 1/4 line port? The port holes actually looked the same between the two in the T. Maybe I'm over analyzing this and it's obviously overkill, but I'm not well versed on reverse flare and how lines and fittings work in junctions.
Red= front right, left green=rear, right green=front left.
As found,
New 3/16 line to the front left, accommodating the new T position. Cunifer line...love it! Original 65 line and fittings to the right front still good to go! Amazing thanks to an oil spewing 250 six?
Blowing thru it was how I discovered the flow difference as well. After several tries (and almost hyperventilating) I was certain there was a significant restriction on one side.
