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Discussion Starter · #1 ·
Hello, this is my first discussion. I have previously posted on discussion "1968 Galaxie XL Power Brake Booster and Master Cylinder."

I have a 1968 Ford Galaxie XL convertible with front disc brakes and have a brake issue. I have restored the power booster, rebuilt the pressure differential and control valve, bought new proportioning valve, and no leaks in lines... but still has a low brake. any suggestions would be much appreciated...Mechanic is at a lose.

PDM
 

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Discussion Starter · #3 ·
Hello PDM,

Your situation could be as simple as 1.) push rod in the booster to master piston needs adjustment and or 2.) Your master is missing or has a defunct residual pressure valve.

It also could be the rear shoes aren't adjusted, or you have a mismatch of parts if the booster has been replaced with another kind.

I recently did a large writeup on the entire brake system overhaul in my '68 XL. I cover these topics and more if you're interested here 1968 Disc Brake System Overhaul

Cheers
Much Thx DesertXL

Since I sent the booster out to be restored, we assume the push rod is adjusted right, but we agreed to recheck. The master came attached to the booster so assumed that ok too, I guess recheck that too. Rear shoes are good and all original part to my knowledge. Part #s match up to car after researching.

Fyi, when lines out master are blocked off pedal is hard.

Car has 1/2 pedal with pressure then after 3 stops red brake light comes on and proportioning valve thumps and shuts system down.

After reading you overhaul, do you recommend using the GM Disc/Disc combination valve in my case?

Thanks again,
PDM
 

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Discussion Starter · #7 ·
Very nice. Not a common option for full sized Ford/Mercury. And the first year for single piston calipers.

Action
You blow my mindo_O. The previous mechanic installed an adjustable valve but was removed recently and replaced with original system.
 

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Discussion Starter · #10 ·
Gentlemen

I got to say, you guys are awesome for sharing this info. Have struggled mightily this past year on the brakes, hopefully this is the solution.
Maybe I should have been more clear also, the caliper are not stock, but everything else I have not changed and looks stock.

The cars RPV is new, so if it is bad its a defect. Mechanic has checked the back drum brakes a few times and is sure good.

The pressure differential and control valve has been rebuilt, but the only answer we have right now is that it is worn inside and not functioning properly.

The GM valve sounds very tempting to try.

This is my pressure differential valve.
Brown Wood Rectangle Font Wall


As always, much thanks.

PDM
 
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