Help! Brakes just gave out on my daily!

[RSchwarzli]

Started my truck this morning (the 1990) and had very little brake pedal resistance. Started driving and I was averaging the pedal about 3/4 way to the floor before getting some pressure in the pedal. Caught a light and my pedal went down all the way with not much resistance and then the park brake and ABS light came on in the dash center. Finished my drive to work but still only getting about 1/4 of useable travel.



As for the brakes, they normally are firm once the pedal has moved about about an inch or two. Brakes should be OK. Just did (well, 3 months/4000 miles ago) my front brakes - rew rotors, calipers, and pad and have had no issues since. Rears were inspected a few months ago and seemed OK.



I did look at the vacuum lines and they all seemed connected.



Any thoughts? I have to drive home tonight and am a little worried! Even more worried about towing my trailer tomorrow! :{



Thanks!



Robert

 

[Simplysmn]

I would check for a leak around master cyl? even look under dash and see if you can see anything on inside that's what it sound's like to me is Master cyl went out . hope it's a easy fix man good luck in your search .

 

[RSchwarzli]

Went and checked master. I do have a leak on the front of the booster that has been there forever (I would gather from the master). I remeber the paint being peeled off when I got it in 2003, but there has been no dripping.



Never thought to check the masters fluid until now. Checked it and there is NO fluid in the front section.



I imagine that is part of the issue! But where did my fluid go? I have not had a leak that I can see.



Second question is, OK, I will fill it. But do I now need to bleed the brakes?

 

[Tippin Spotted Cow]

Hmm... had that happen... twice. First time I caught it was down a rather steep hill out of my neighborhood into a slightly busy street with trees blocking my view of if anyone was coming or not and luckily was able to wing it around a hard right turn without getting hit. Drove to work in 2nd gear so when I needed to stop I just let off the throttle. There was enough pressure in the line to stop it from about 10 mph and hold it, but nothing more than that.



Second time It happened I blew a line doing 60 and much to my dismay, the pedal hit the floor when I came up to the stoplight (where vehicles were already lined up). Once again, I downshifted and managed to hang a right past all the sitting cars and limped it over to a buddys house to fix the line.



If you have pressure from 3/4 to all the way to the floor it probably means you have a leak on just one side of the system. We have divided master cylinders, so if you pop a line on the rear brakes, the front will still work, and vice versa. A lot of times the lines break right at the fitting, especially if there's a bend right as the line comes out of the nut. If you can get somewhere to find a line, it's an easy fix, and I wouldn't tow a trailer without fixing it. You can isolate where to look for the leak by which side of the master cylinder reservoir is empty. Topping that off might help you get around in the mean time, but depending on the leak, you may bleed it out faster than you can fill it up.

 

[Tippin Spotted Cow]

If you got air in the line *technically* you should bleed the brakes. Me, I'd just drive it, because I'm an idiot. If the master cylinder emptied once, it'll do it again. When you replace the line that's leaking, you will need to bleed the lines then. I'd put it off until then though. Sometimes leaks in the brake lines are hard to catch, because (duh) they only leak when you hit the brakes. Turn the truck off and have someone pump the brakes while you crawl around under it. You'll most likely hear the source right away.

 

[RSchwarzli]

Will try that tonight if I make it home alive!

 

[kenny61]

often the master cylinder will leak into the power booster and you will never see a leak until you pull it off

 

[RSchwarzli]

Comforting...



Just filled the front section with fluid. Brakes work better. Had someone pump the brakes and did not see any fluid leaking anywhere in the lines. Even the elbow looked good.



Will haveto keep looking. Maybe even pull the booster off.

 

[JLEONARD]

The only 2 times I had no or little pedal was when brake lines rusted thru.

I wouldn't recommend towing a trailer until you get it solved for sure.

You are not driving thru Connecticut are you?:-laf

 

[Tippin Spotted Cow]

I could be wrong, but I think if the master cylinder leaked into the booster both halves of the reservoir would empty out, not just one.



Here's where the issue comes in... and this is why towing is a bad idea until it's fixed... They most often break due to rust, and usually in areas of a bend. A lot of the bend sections are covered with those metal coil-like sleeves to prevent abrasion. That sleeve could hide where the real problem is. Add to that, if it is rusted through a bend like that, it WILL get worse and worse very rapily. Once the hole starts, its only a matter of time before the line severs entirely. You'll be walking on clouds in your false hope of having solved the problem by filling the reservoir and BAM! just like that your brakes will be gone. When that line does sever, all it takes is one pump of the pedal to basically empty that half of the system.



Don't ask me how I know.....

 

[RSchwarzli]

Jay - I was going to come see you in CT but since you feel that way...



Mr. Cow - Yup, I agree. Guess I will be doing some 'vestigatin tonight. See what I can replace/repair.