Brakes Rubbish At Slow Speeds?

[funbus]

noticed several times that the brakes seem to be almost non-existent when crawling in traffic sometimes, and today very nearly rear ended a car whilst trying to stop quickly from about 20mph. Brakes seem to have no servo assist at slow speeds, is this just the way there are? Does anyone else get this? Or is this a symptom of some sort of issue? ps brakes are perfect at higher speeds.

[strouf]

The brakes on mine have the same (good) performance at low and high speed...If you feel there's not enough servo assistance (pedal is hard to push when engine idling, or at low revs) you should check the vacuum hose(s) for air leacks .

[tim-spam]

Most likely cause is a split servo hose - at higher engine speeds, the vacuum pump can shift enough air to sustain a reasonable vacuum in the system, but if the split gets worse, you may find stopping a little tricky.

Is the engine also a little rough when you switch it off?

[funbus]

Most likely cause is a split servo hose - at higher engine speeds, the vacuum pump can shift enough air to sustain a reasonable vacuum in the system, but if the split gets worse, you may find stopping a little tricky.

Is the engine also a little rough when you switch it off?

 

cheers guys I will check the servo hose, probably replace it anyway just in case, as this problem does need to go away as it isn't very safe.

 

Rough at switch off? I hadn't really noticed but I guess it could be described as a bit lumpy. Why, does that have something to do with the vacuum pump?

[funbus]

Fixed this problem now. It was the first time I tried to use the TIS as a reference, my goodness no wonder ford dealers have such a bad rep if this is what they use, I'd have been better off banging my head against a wall.

 

Anyway the symptoms were that the brakes were fading at low revs after several presses of the pedal. So, foot off accelerator, press brake, foot off brake, brake again, foot off brake, then on 3rd braking the brakes were almost non existent. Loss of vacuum at idle. This as correctly pointed out to me was a vacuum pipe problem - thanks for the advice. Just behind the fuel/brake booster pump is a check valve with an ehtylene pipe attached that runs back behind the heat shield to the bottom of the servo (or maybe master cylinder can't remember which) on the other side of bay. The pipe was split where it joins the check valve. To replace the whole pipe would have been a total mare, so instead we wrapped self-amalgamating tape around the split. This tape moulds itself together over time to form solid lump. Way easier and cheaper and quicker than replacing pipe. Problem solved. Brakes sorted.

 

(And also found the manifold vacuum pipe was split where it enter the intake manifold so cut the end off this and resealed. Now the gal picks up from low revs loads better.)