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smoking brakes (poor brake power at rear disc) FIXED

4K views 18 replies 7 participants last post by  zzyzzx  
#1 ·
good morning: as the tittle says my front brakes are smoking, to too much but i can smell the smoke too. So i have too much brake power at the front and very less at the back (rear disc no ABS)

yestarday i bought a Mityvac from autozone, so i test it in the front brakes, when i started to bleed and open the bleeder screw the piston start to take it back then the fluid start to coming out, i fill the mityvac cup and move to the next front wheel, the pedal feel better and the car brakes better but with no rear brake power.

when i´ve notice that when the front brakes start to smoke i lost rear brake power, i don´t know why because my e-brake are working good.

what could it be that i have problems in the rear disc brake system, the hardware are new (bolt pin, sleeves, boots, etc)
- a stuck piston?

yesterday i put the rear wheel on the air and start to spin it, when i barely push the brake pedal the caliper start to close and wheel stop.
when i release the pedal the wheel are completly free, so what else can i check

i know that i need to bleed my rear brakes, i think today after work, but any advise

my 97 SOHC brake system always have been a PIA for me, i want to buy a ZX2 but with this brakes problems i have doubts.

please any advise
 
#2 ·
I am guessing; that it is possible your front brake calipers are not moving sideways on the "guide pins". As the pads wear, the caliper has to be able to slide a tiny distance sideways so the outer pad wears as much as the inner pad. The two bolts that hold the caliper to the steering knuckle are both long, and fit down the middle of two hollow cylindrical steel rods. Those rods should be able to slide in the caliper. If you were to take the pads out, you should be able to push the caliper sideways -horizontally- about 5 to 10 millimeters - just using your hands. On many of our Escorts they are either stuck in place, or are very hard to slide. This will make one brake pad wear faster, and run hotter.
It is possible to dismantle the caliper, push the pins out, and clean the rust from them. It takes a lot of time. In the USA most of us buy rebuilt calipers, because it is faster and the rebuilt calipers are not very expensive.

The rear brakes only do about 25%-40% of the work of stopping the car. The front brakes do most of the work - so will get hotter.
 
#3 ·
thanx denisond3, but last month i replace all front caliper hardware again, also the piston ring and dust cover, and yesterday when i purge the front ones i checked the movement of the cliper and they are ok,

i remember that last year i have both front caliper sized so i replace the bolt pins and sleeves and and lub them with sil-glyde. I´m sure that my front caliper move freely.

my concern about the low pedal it´s that my Forde Service manual says that if you have low pedal one of the reason could it be stuck rear caliper or piston. I´m going to replace both piston seal and dust cover of the rear ones and clean and lube again.

i´m loosing brake power so i´m loosing hydraulic pressure, and if i don´t have any leaks and any air in the system i have some thing wrong that provoque that the prop valve release pressure in the back system, i think that why the Service manual says about the rear calipers
 
#6 ·
more then likely the piston seal is leaking fluid and is starting to smoke when the brakes heat up, this will also cause a soft pedal and will pull a little air into the brake system when the pedal is released, i would check the rim for fluid residue and also check the caliper for a grease black film. If you have been driving like that for a while the brake rotor will be glazed (very shiney and smooth). You could rebuild the caliper depending on your skills and availability of parts or just get a reman caliper with a warrantee
 
#7 ·
ok i need to take again this problem

i replace everything, check this

- new front caliper hardware (everything)
- new front caliper piston seal (square ring and dust cover)
- new front rotors and pads (ceramic)

now the car don´t smoke but i still have a low brake pedal one in a while, not all the time.

sometimes the brake pedal are high and good, but sometimes low but with low brake pedal.

what can i do, i purge, and purge and purge, even with positive pressure from the deposit to each wheel, no air comming.

what else can i check, my problems it´s that this high low brake pedal are occacionally
 
#8 ·
Have you ever replaced or rebuilt the master cylinder? If it's worn fluid can leak by the pistons and cause the low pedal problem. It can also stick, which would cause the fronts to lock up since they are closer to it.

On a '97 if it's the original i would guess that it's way overdue even if low miles.
 
#14 ·
maybe stuck caliper pistons?

good morning: yestarday i made the hose clamp test on the front caliper. the pedal height increase very well, so i releale them and the pedal sink, so i´ve notice that my problem ara in the front caliper

i jack the car and check the calipers and both was very good,you can move freelly, no stuck pins and sleeve, but i cleanned a lube them again.

so, what could be my problem, stuck caliper piston?, i´m sure that i don´t have air in the system, the seal of both caliper pisto was replacer since 3 month.

i replace them because old, not because a leak. but why my front caliper doesn´t havce power to brake?

sometimes they brake good, firm pedal, but and sometimes it´s sucks?
 
#18 ·
Sounds like one of your calipers may have a sticking piston or stuck slide pins.
 
#19 ·
Those crappy brass plated pins that Mazda uses to hold the brake pads in suck and really can't be cleaned well enough, they will only rust again soon. I do use the term "brass plated" loosely since it might just be brass colored paint. You will need to get new ones, preferably each time you replace the pads. The same is true for the "springs". This is yet still another mistake Mazda made on this car. All those items should have been made with stainless steel.