Hydraboost:Troubleshooting

[79_Conti_Mk_V]

My 79 Has always had bad brakes, the kind that you wonder if you are going to stop....because the pedal only sits like 1/2 inch off the floor when the brakes finally catch..


I was wondering what are some signs of the hydraboost failing, and what i could do to fix it, or possibly replace it with a more traditional vacuum boosted brake setup?


Any input is appreciated! :D

[Bluegrass]

I have little experience with that system but to suggest you get to a library and look up a book that addresses that system.
You are risking accident by continuing to drive the car in that condition.

[79_Conti_Mk_V]

Well it hasn't started road duty yet, and it won't till i either until its repaired. I don't want anything to happen to this car, just because of its age and its semi-rarity...and i wouldn't want to harm anyone else by my dumb mistake.

But yeah, i'll hit the books tomorrow and check out what i cant do with it.

[Bluegrass]

Great, I didn't know if you were trying to drive it or not.
You would be surprised how many will try to drive a car with a problem.

[79_Conti_Mk_V]

Something that has just occured to me, my dad replaced the m/c on this car about a year or two ago. I seem to recall him replacing it with a truck master cylinder if im not mistaken. Could this be causing the braking issues?

Also i noticed today after bleeding the brakes,(there was no air in the lines)that the m/c was full of rust on the inside... so that leads me to belive i need to swap the m/c out again, and re-bleed the system.

[Bluegrass]

I would go with a new m/c but there is fear of blockage in the system now. The proportion valve may be blocked.
I would dissasemble all lines and blow air to be sure there clear.
Going used for these items seldom is worth it in the long run. ;)

[79_Conti_Mk_V]

As i recall the m/c he bought was new...so i don't have a clue as to why it rusted out on the inside of the cylinder, thats what has me puzzled. Since it was installed the cap has maybe been off of it twice....maybe. and never left off for more than a few seconds to check the fluid.

hmmm....curious :confused:

[Bluegrass]

The old fluids attracted moisture and was a prime killer of system parts unless flushed at times.

[Steve Moran]

I will give you a little advice. The one thing I had been preached to during the years is not to shake the can of brake fluid because it will cause air bubbles that will make it harder to bleed the system, and also because it can cause the system to rust from the inside.
Bluegrasses suggestion of cleaning out the brake line is well advised.
And yes any other master cylinder other then what is set up for the system on the vehicle usually results in a problem.
My educated guess is that it is made for drum brakes and dose not put out the capacity needed for the calipers on a disk system

[79_Conti_Mk_V]

Well, i asked my dad what he asked for when he bought the new MC and he said an 80's F-series truck, so... i think it should be able to feed the brakes of the lincoln.. but, i don't think the pushrod is long enough to make the brakes grab all the way, resulting in the soft pedal that i've got.

Hopefully swapping the m/c out will rid me of these bad brakes once & for all.