No brake's!!!! Need help

[BroncoBrandon]

I have a relatively simple question.

Does a master cylinder go bad quickly?


My Bronco had been sitting for a few months due to the heat here in AZ and having no AC when its over 110 is not all that enjoyable.

I went to move it the other day and when I tried to stop it kept rolling till the peddle was almost to the floor. When I parked it before summer the breaks were fine.

The peddle will return to the regular position without a problem but can be depressed with nearly no pressure applied.

I checked the reservoir and it was nearly empty and there are no puddles or noticeable leaks that I have found.

I need help/Knowledge/advise or possibly a swift kick and the truth. Does it sound like the master cylinder went bad or just fluid level got low and needs to be bled?

 

[B RON CO]

Hi, the master might be fine but fluid loss is a problem. You should never lose brake fluid. You may have a bad connection, bad wheel cylinder, caliper etc. You should pull all the wheels and look for a leak. Pull back the rubber boots on the wheel cylinders and inspect for leaks and rust. Nasty tings can happen when the Bronco sits in storage too long. Can you fill it and bleed it? You must take care of this for saftey. Good luck

 

[dave67fd]

Refill the Master and pump the brakes then look for leaks. Your brake system is/should be sealed so you shouldn't loose any fluid. If it's leaking you'll see it sooner than later. If it's not leaking, rebleed the system. Typically start from your furthest point to your closest. Also tell us what system you have, drum, disc/power?

 

[BroncoBrandon]

Thank you both for your input and assistance.

The current break system is the stock master cylinder, disk in the front and drum in rear.

I'm going to fill the system, bleed and check for leaks tomorrow.

I will let you know how it goes.

 

[DirtDonk]

Look for leaks up under the dash too, where the rod from the pedal goes through the firewall. They can leak there as well.

Unfortunately, the answer to your first question is "yes" a new master can go bad right away. It's not in the design, it's in the crappy parts we have available to us these days. I consider someone lucky when a part they buy is not bad right out of the box!
Sad but true...

And as said, a little use and then sitting just makes it worse. Fuel pumps are notorious for this kind of failure.
But nothing with seals likes to sit unused for a long time. Yours just wasn't that long.

Good luck.

Paul

 

[Apogee]

The only reason your fluid level should ever drop in the master cylinder would be due to pad wear on a disc brake axle...that's it. Wheel cylinders always return to the same resting position hydraulically speaking, hence the reason they usually have a smaller reservoir since they don't need to account for shoe wear like calipers do for pad wear.

It's also good to be aware that if you see any signs of corrosion in the system, either in the MC reservoirs or the fluid you bleed from the system, you can fail the MC quickly during the bleeding process since the seals will stroke more of the MC bore than usual, making contact with whatever corrosion and/or pitting may have occurred there.

 

[Broncobowsher]

Loss of fluid = leak. You just have not found the leak yet.
Was it just one reservoir that was empty? That can cut your leak search nearly in half.

 

[BroncoBrandon]

Thank you guys for the help.

It turned out to be the wheel cylinder on the drivers side drum.

It holds pressure but it has a small leak and that's why I didn't notice a puddle of fluid. A new one will be on order soon.

 

[B RON CO]

Hi, a lot of guys will change both. Not necessary but think about it. And bleed a lot of brake fluid. Get new bra fluid. Brake fluid absorbs moisture and that allows rust to form. Good luck