hi. Sometimes it is very hard to stop the car while especially driving downhill and when the car is loaded. I had to fully press brake pedal and force it very hard to stop. brake pads are ok and discs also seems ok. while I was driving my old vw passat pressing brake very gently was enough to stop it completely. do brakes behave like this on your car too?
Sounds like your rotors/disks may be getting over heated. Even if the pads and rotors are smooth, they can be too thin to absorb the heat properly. Another area that can effect brake performance is old contaminated fluid.
Your symptoms would suggest they need some sort of service.
Mine are getting to be the absolute shits too - it's nearly impossible to make the car stop hard enough to activate ABS.
They flash rust in rain and after three days of disuse they're like sandpaper and a 1924 Lea-Francis probably stops better. German discs are atrocious. Never had these issues with a Peugeot 405 in 366,000 km....
I need to buy new rear calipers, new rubber hoses (I expect) and 4 discs and maybe that will sort it out. Will do that around 300K km. Last investment in the car before she's replaced in a few years' time.
Make sure that all 4 calipers are travelling in and out smoothly... You would have to remove the wheels and manually push the pistons in ( a "C" clamp is a simple way to check this..) and see if they all move in with the same effort.
Remember to protect the pistons from coming out too much if you apply the brakes with the calipers free..
For the calipers again..
If not, you might have corrosion behind the caliper piston and out of sight. One reason why we change the brake fluid on a regular basis..(usually 2 years..for the fluid..)
I would also make sure that the caliper guides are moving in and out freely.... The brake pads should always be free and movable..along with the calipers pistons..
If anything is too tight (possible due to rust..), the brakes will not stop the car properly....
My B stops very well, but I have to keep on top of the floating parts..
Check your brake booster and the vacuum plastic hose and connections to it from the intake manifold. The line runs over the air box around to the front of the engine.
Search youtube for "check brake booster operation" to understand the 'pedal test' with engine on and off and the response you should get when you hold the pedal and start the engine.
I was already wondering about it, and moreso now that you mentioned the AC on making it worse. Usually, the engine management adjusts idle to compensate for the additional load of the ac compressor. This usually affects the vacuum the engine produces. Only doubts I have about this being your problem are that the vacuum should not change much, and the brake booster is not a common problem on these cars AFAIK.
I'd still check the above since it's free, quick and easy, but make sure the pads/rotors/calipers/sliders/fluid are good and fresh.
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