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bad master cylinder?

Little help diagnosing a brake problem, plz... ('87 5.0 LX)

Recently, maybe 2 weeks ago, I noticed that the brakes were feeling especially squishy and unresponsive. Being a bit lazy, I just let it go for a few days, thinking that I probably just need to add some fluid, since it had been a long while since I even checked it last. A few days later, sure enough, I went to check the brake fluid level, and it was seemingly empty. I also noticed, to my chagrin, that there seemed to be a decent amount of leakage on and around the master cylinder.

After filling it up, the brakes seemed to work a little better, but not as much as I had hoped. I also noticed that I was able to stop much easier (by pedal feel) when I pumped the brakes a few times before coming to a stop. It's been a few days now, and I've pretty much gotten used to adjusting my braking habits and nothing seems to be getting any worse, but since this is my braking system after, I'm thinking that I should probably get it looked at by a pro. In the mean-time, I'm wondering if this is a typical sign that my master cylinder needs to be replaced?

I think I had this part replaced only about 30k miles ago, after my original was diagnosed as 'shot' with ~140,000 miles, and I seem to recall that the repair bill was fairly high :(

I guess, in my own stupidity, letting the fluid levels get so low could have significantly damaged something prematurely?

I'll probably take it into a shop sometime soon to get it looked at, but I like to hear some feedback from others, just to get some additional info, and/or things to watch out for, etc...I'm at a bad point to spend a lot of money on car repairs right now, but if I have to, I have to.

TIA

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Reply to
jake lee
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Well, if the fluid level was low then you have a leak. The hydraulic part of a brake system is a "sealed" system. If you have to top it up then there is a problem. One of the biggest problems associated with the hydraulics is that regular DOT 3 fluid absorbs water and eventually the water will damage the steel and alloy parts of the system. If the bores of the cylinders get pitted due to rust or corrosion eventually the seals will leak. Cars that are stored a long time especially in cold climates often suffer cylinder failures due to water condensing or freezing out of the fluid and pooling causing such pitting. Water is also bad as it has a tendency to boil when hot under extreme braking and turn to steam which is very compressible and DOES NOT work in a brake system!

It would seem that your master is shot by your description or there may be a loose connection causing a slow leak. This would be a great opportunity to bleed the entire system if you replace it or examine it for leaks, possibly curtailing any further damage in the lines, wheel cylinders and calipers. The flex and hard lines should be looked over while your at it.

StuK

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Reply to
Stuart&Janet
** I also noticed, to my chagrin, that there seemed to be a decent amount of ** leakage on and around the master cylinder.

The last time I saw this on my own car in 1979, I ended up rear-ending an old lady in a Pontiac the very next day because the front half of the brake circuit completely failed. The pedal went completely to the floor, and I had no control where the damn thing went.

My advice: get it to a professional ASAP. Do not drive it there - have it towed.

Regards,

-JD

--------------------------------- JD's Locally-Famous Mustang Page: http:/207.13.104.8/users/jdadams---------------------------------

Reply to
JD Adams

Just a follow up on the other posts. Excellent advice. If this is not something you can do take it a pro for a complete inspection. Sounds like the master cylinder is leaking somewhere. If you let the fluid level get too low you may have introduced more air to the system. At the minumum you need to bleed the system very good. You may have to bench bleed the master cylinder and don't forget the rear drum cylinders. They are prone to leaking in a car this age. Just don't procastinate, Claud

Reply to
Claud Spinks

Thanks guys for the nice input. I just dropped my car off at my local shop and am currently hoping for the best, but basically expecting the worst as far as far as cost to repair goes. I've generally been one to take some chances now and then with my various car problems, but when it comes to braking problems, it really can (fairly easily) be a matter of life and death(s) to let it go unchecked for too long. A large repair would certainly seem to be a fair alternative, when put into that perspective.

Just once I'd love to have a leak be due to a loose clamp on a hose somewhere,...:::sigh:::

Thanks again!

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Reply to
jake lee
** Thanks guys for the nice input. I just dropped my car off at my local shop ** and am currently hoping for the best, but basically expecting the worst as ** far as far as cost to repair goes. I've generally been one to take some ** chances now and then with my various car problems, but when it comes to ** braking problems, it really can (fairly easily) be a matter of life and ** death(s) to let it go unchecked for too long. A large repair would ** certainly seem to be a fair alternative, when put into that perspective. ** ** Just once I'd love to have a leak be due to a loose clamp on a hose ** somewhere,...:::sigh:::

Not to worry; this kind of diagnosis/repair won't cost an arm and a leg. I don't fool with hydraulic leaks on the brake system. If I don't think I'm qualified to repair it, off it goes to an expert.

It could be worse. I just changed out the radiator on my Winter Beater, and lo and behold - it has a factory defect, right out of the gate. I was embarrassed as hell watching it hemmorage all over our parking lot this morning. Thanks, Autozone! It has a crack in the thermoplastic that pretty much renders it useless. And I get to spend another 4 hours on a Saturday changing the damn thing out...again.

Regards,

-JD

--------------------------------- JD's Locally-Famous Mustang Page: http:/207.13.104.8/users/jdadams---------------------------------

Reply to
JD Adams

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