Here we go again.............master cylinder!!!!!!

[Toploader]

So as many of you remember back in July I had a new master cylinder put in my '86 Tudor as the brake pedal was was going to the floor and i had no brakes, and yes upon pumping I would again get a pedal. Well due to health issues I have only moved the car 2 times per week to make way for the city street cleaner. Yesterday again the brake pedal went to the floor. So do I now have to get yet another master cyl, or can something else cause the pedal to go to the floor. The bowels remained full so I assume none of my wheel cyls are leaking?
Thoughts????????

[friskyfrankie]

So as many of you remember back in July I had a new master cylinder put in my '86 Tudor as the brake pedal was was going to the floor and i had no brakes, and yes upon pumping I would again get a pedal. Well due to health issues I have only moved the car 2 times per week to make way for the city street cleaner. Yesterday again the brake pedal went to the floor. So do I now have to get yet another master cyl, or can something else cause the pedal to go to the floor. The bowels remained full so I assume none of my wheel cyls are leaking?
Thoughts????????

Haven't seen you, in a while, so hope all is well, health wise. As for your issue, it could be many things including air in the system (which probably would have been noticed up front), caliper issues, bad MC (I recently went through THREE until I found a good one, out of the bx, for my friend's '88) or a bad booster. Might have left some things out but I'd look at those first. Are all the other parts (pads, shoes, drums, etc) OK?

[Toploader]

Pads new, rear shoes good. But for three months I had no issues, now as I said yesterday morning the pedal went to the floor, then came up and I had a hard pedal. Booster has plenty of vac reserve as I have no issues when I apply the brakes. My bud is a great dude, but I can hear him now when I say I need to flat bed the car back out to Long Island.
Thanks for your thoughts concerning my health, I go to the hospital once per month for my chemo meds, LOL I even have the word out as to the sale of my Avanti, its been a great run since 1967, but with the storage garage out on Long Island and my health issues, well time to put the keys into the hands of someone who will hopefully care and love the car as I have for all these years;-)

[WagonMan]

Sorry to hear your "bowels remained full", maybe you should try Exlax! LOL! WagonMan

[Toploader]

Sorry to hear your "bowels remained full", maybe you should try Exlax! LOL! WagonMan

Peter you are too funny;-)

[Tiggie]

I'd put a master cylinder on it again.

[friskyfrankie]

I'd put a master cylinder on it again.

I mentioned that for the reason stated above. I have seen some bad out of the box and some that fail a very short time later.

[Toploader]

But here are some thoughts, I will "assume" I need another M/C, if the brake hoses were internally pinched, or collapsed from age, there would be a situation whereby the brakes would not release fully, no? ...........I have no brake dragging situation, the front pads do not even have 500 miles on them, the rear shoes still have lining good for at least several thousand miles, the booster provides the proper "boost" as the brakes apply normally, as to air in the system, I have a hard non mushy pedal, if the booster was sucking fluid inside, my M/C would not remain properly full, At any rate I am open to all of your thoughts...............as all new M/Cs seem to be made in China I would think the Dorman on there now would be the same as a new Raybestos?

[Toploader]

The other ride

[friskyfrankie]

But here are some thoughts, I will "assume" I need another M/C, if the brake hoses were internally pinched, or collapsed from age, there would be a situation whereby the brakes would not release fully, no? ...........I have no brake dragging situation, the front pads do not even have 500 miles on them, the rear shoes still have lining good for at least several thousand miles, the booster provides the proper "boost" as the brakes apply normally, as to air in the system, I have a hard non mushy pedal, if the booster was sucking fluid inside, my M/C would not remain properly full, At any rate I am open to all of your thoughts...............as all new M/Cs seem to be made in China I would think the Dorman on there now would be the same as a new Raybestos?

Not sure ANY M/Cs are still made here but you can check Willwood or Brake Performance out of California. I believe they are still made here. They "may" have a part that fits. My only concern is that the castings and other parts may be made "elsewhere" with just the assembly here. By the way, the Avanti is "sweet"! If you are looking to sell it, you can PM me the details (asking price, lowest you would accept [I'll keep that under my hat], etc) and I'll pass it around some folks I know down here

[sly]

But here are some thoughts, I will "assume" I need another M/C, if the brake hoses were internally pinched, or collapsed from age, there would be a situation whereby the brakes would not release fully, no? ...........I have no brake dragging situation, the front pads do not even have 500 miles on them, the rear shoes still have lining good for at least several thousand miles, the booster provides the proper "boost" as the brakes apply normally, as to air in the system, I have a hard non mushy pedal, if the booster was sucking fluid inside, my M/C would not remain properly full, At any rate I am open to all of your thoughts...............as all new M/Cs seem to be made in China I would think the Dorman on there now would be the same as a new Raybestos?

yes, pinched lines would create a slow or no release condition. Rolled seals in the master can also cause the pedal to go to the floor and then they seat on the way back up and work after that. It can be a PITA to diagnose. Rebuilding the master or just replace (for free if under warranty) will solve that. Also, the proportioning valve can cause all kinds of sticky brakes like a pinched line if it's triggered.

[gadget73]

How long has it been since anyone had eyes on the wheel cylinders? The seals in those can roll in and do the same thing as in the master cylinder, especially if the back shoes aren't properly adjusted. There is supposed to be a residual pressure valve in the system that keeps pressure on the rear cylinders to keep that from happening but it might leak back, or if the wheel cylinders leak outward that will bleed down and let this happen.

[Toploader]

If the hoses are pinched would they not be pinched all the time?............meaning I have an intermittent situation, hoses are either pinched or not pinched, no?

[Toploader]

How long has it been since anyone had eyes on the wheel cylinders? The seals in those can roll in and do the same thing as in the master cylinder, especially if the back shoes aren't properly adjusted. There is supposed to be a residual pressure valve in the system that keeps pressure on the rear cylinders to keep that from happening but it might leak back, or if the wheel cylinders leak outward that will bleed down and let this happen.

Thain last I checked the rear cyl were not leaking, but eff it, I will have the car flat bedded back out to LI and tell my bud to just put in new rear cylinders and new hoses, LOL I am getting too old for this Sheet!

[gadget73]

If the hoses were pinched the pedal wouldn't go to the floor. Either you'd get a hard pedal and no brake, or more commonly the brake caliper drags. Pedal to the floor is loss of pressure or something moving further than its meant to.