Soft brake pedal on '85 GT

[Trick Pony]

Totally stock brake system. They were working fine with no changes made but now when I push on them the pedal goes to the floor pretty easy and the brakes barely work.
I checked the master cylinder and the fluid is not low. There are no visible leaks anywhere at the m/c, calipers, wheel cylinders, or any threaded fittings.
I have heard that bad seals inside the m/c can cause this. Anything else it could be based on these symptoms?
I've had bad boosters before but they made the pedal hard, not soft so I wouldn't think that's the problem.

[mstng86]

Subscribing. Mine is doing this right now. I have been told it is the m/c.

[garycrist]

Master Cyl. Pump up the brakes, then push moderately to lightly till it goes to the floor. That will confirm it's the master as long as there are no leaks.

[Snatch Napkin]

Master cylinder is the most likely culprit.

Take this time to replace the soft lines going to your front calipers, flush your lines out completely, and refill with new fluid.

Remember to begin the bleeding process at the furthest point from the master cylinder, the passenger rear.

[Gargamel]

Master cylinder is the most likely culprit.

Take this time to replace the soft lines going to your front calipers, flush your lines out completely, and refill with new fluid.

Remember to begin the bleeding process at the furthest point from the master cylinder, the passenger rear.

^^^
This

You may want to go ahead and put on some braided lines while you're at it...

[bonnie&clyde]

what is the order to bleed them??

[Snatch Napkin]

Yeah, if you have the extra cash, then braided lines are the only way to go. They will increase pedal feel on a properly working system.

[Snatch Napkin]

what is the order to bleed them??

passenger rear
driver rear
passenger front
driver front

[mstng86]

Anyone use a particular brake bleeding kit?

[Vertnut]

Anyone use a particular brake bleeding kit?

A good friend?

[mstng86]

A good friend?

Cool, where can I buy one?

[Trick Pony]

I've been planning to go 5-lug with disc all the way around so this might be the time to do it then. Thanks for the input guys.

[Snatch Napkin]

Anyone use a particular brake bleeding kit?

I have yet to have found a brake bleeder kit that works as well as two people.


The next closest thing was putting a vacuum line into a jar of brake fluid, but that was because I was alone on the side of the road.

[Vertnut]

I have yet to have found a brake bleeder kit that works as well as two people.


The next closest thing was putting a vacuum line into a jar of brake fluid, but that was because I was alone on the side of the road.

My experience also. A quart of fluid, a buddy, and a little patience is all it takes.

[JimD]

I do them all the time(myself) at work with a vac pump. I do let it gravity bleed first tho.