long time listener, first time poster.
I have a Ford escort 94 station wagon with a brake problem. I have brought it to the shop, with no real improvement. The brakes are really weak when I start up the car, and they are not really brakes but decelerators. After I have driven a couple of miles, the engine gets warm, and the brakes get better, though never super and I couldn’t block the wheels no matter when. The problem is worse when the weather is really cold. When I brought it to the shop, they diagnosed a problem with the vacuum, it was very slow to creep up after an engine start. They found a cracked vacuum line and replaced it, and it was better for a while, but not as good as it should be. I was wondering if anyone here has a good idea what it could be, because I don’t think the vacuum lines are the problem as it gets better as the engine warms up. Thank you for your input!!!
I would guess they found one leak, but there may have been more. It still sounds like a vacuum leak to me.
What happens when it is stopped and you have your foot on the brake? Does it stay there or does the peddle slowly go down?
You don’t want to let this one slide very long. I could cause an accident.
wow, that was faaaast.
When I put my foot on the pedal, it goes down and doesn’t sink in further.
As for a vacuum leak, would warming the engine also warm a leaking hose, slightly tightening the leak thereby improve it?
Some more info is needed to even be halfway definitive.
Is it known for a fact they checked the vacuum in the correct place? (This means the intake manifold, not ported vacuum above the throttle plate. The latter will be low at idle and that’s normal.)
If the vacuum is abnormally low that could be caused by any one of a number of things. It would help to know what the reading was at idle.
If the vacuum gauge is sluggish upon startup that could be due to an exhaust restriction (converter usually) and this has an affect on manifold vacuum. Do you happen to know what that vacuum gauge was reading?
Another cause of weak brakes is worn or out of adjustment rear brakes on rear drum brake cars. This can cause a low pedal and weak braking characteristics. The reason it may improve some when warmed up is because the brake fluid expands a bit with heat.
I’m sorry, but I don’t know where they did the vacuum readings.
I don’t remember the exact vacuum reading, but it was somewhere about maybe a quarter of what it should be, and it kept creeping up, albeit very slowly, and then leveled off maybe at half of what it should be after a couple of minutes.
I had the brakes replaced recently, as they were indeed worn out, but they should be good now.
Thanks for your input!
If the vacuum reading was taken at the intake manifold as it should be and it’s abnormally low this could be caused by a vacuum leak, exhaust restriction, worn engine, cam timing being off a tooth or two from a timing belt replacement, EGR sticking open a bit, etc. Without knowing the details behind the gauge reading it’s difficult to make much of a guess.
The vacuum reading will vary based on different factors such as altitude, barometric pressure, engine condition, etc. but normally a good engine with no vacuum leaks will show about 17 to 20" of manifold vacuum at idle. This also means a rock steady gauge needle. You start getting to 15" and under there’s a problem.
My point about the brakes is that even with new drum brakes on the rear the pedal can be affected if the new rear brakes are not adjusted properly. Too much free play in the brakes causes the pistons in the wheel cylinder to have to move out much further than they should. This in turn translates to much more fluid being needed to operate the shoes and the brake pedal will sink accordingly. Hope that helps.
Somebody ought to put an actual compression gauge on it before you spend anymore time or money on the car.