@imranbhattiStarlet has front disc brakes and rear wheels drums.Disc brakes have better braking power than drum brakes.To lock wheels equipped with drums,you need to apply more force on the pedal to stop vehicle but in your case the force gets utilized mainly by your front wheels via oil pressure and the rear wheels dont get the required pressure to lock them(cause can be un adjusted leathers).
Drive a Suzuki Bolan(is equipped with drums(front & rear)which is a rear wheel drive vehicle.You will feel sluggish brakes and when you forcefully apply the brakes, all wheels will lock(Only possible if all leathers are properly adjusted).
Drive a Pakistan assembled corolla xli,gli,2.0d,se-saloon or civic exi(all equipped with all wheel disc brakes without ABS),all wheels will lock up on hard braking.Corolla master cylinder applies more pressure on normal braking thus wheels lock up easily(Corolla cylinder was designed for better braking force but due to all wheel disc brakes,the vehicle sways from behind if steering wheel moved during hard braking due to wheel lock up.Japanese model has same cylinder in there vehicles but all are ABS and most of them have rear wheel drums(X grade cars mostly),even the indian assembled corolla).My point is that for all wheel disc brakes equipped cars it is essential that they have ABS technology or the driver should be careful at high speeds and avoid steering movement during hard braking.
POINTS FOR DISC OR DRUM BRAKES:-
1.Disc brake pads lasts longer than drum brake leathers(Disc around 30,000km-40000km and if all disc then 50000km to 60000km whereas leathers 30000km-40000km while if all leather then 20000km-25000km--mainly front wears first)
P.S In front disc and rear leather vehicle,the leather life is increased as the front disc mostly absorbs the force during braking & they become un adjusted during there service tenure resulting in less usage.The brakes life decreases by driving in hilly areas,mostly in city,sudden acceleration & applying hard brakes.
2.Disc pads require no service at all during the tenure of its service whereas leather require service every 10000km and 5000km if used mainly in hilly areas.
3.Vehicles with all drum brakes tend to turn on applying brakes on their sides due to un adjusted leather as one wheel locks up while other is free(common cause of accidents esp at high speeds)
4.Disc pads wear can be sensed by increase in gap of brake pedal while applying brakes + decrease in the brake fluid oil level whereas drum leather wear can not be sensed by brake pedal gap as it can increase even when the leathers are un adjusted & there is very minimal amount of change in brake fluid level thus barke condition cant be judged thus frequent inspection of leathers is required.
5.Vehicles with drum leathers mostly develop brake leather cylinder(located in the wheel drum) leak without a warning thus resulting in brake failure at any time.Most common cause is due to wear out of brake leathers(imagine you are driving at 100km/hr and you apply brakes ad find out this phenomenon) whereas if disc pads wear out they produce a squeeling sound but driver is able to drive vehicle to destination with mild loss in braking distance.
Mostly all wheel drum vehicles are rear wheel drive due to the unstability this type of brakes causes at high speeds.All older vehicles mostly below 1975 had all drum brakes but these vehicle engines & technology would not permit them to go over 100km/hr to 120km/hr.During this era,it was realized by increase in number of accidents, the need for a newer type of brakes which will insure more vehicle stability and control at higher speeds and thus disc brakes were invented.After invention of these brakes it was realized that braking force and stability of vehicle has drastically increased but the wheels lock up easily and under poor road conditions result in accidents.
Thus around 1986 the ABS(Anti-lock Braking System---brakes are applied via pulsating movements of the disc pads with the disc rotors) technology was introduced which reduced number of accidents drastically which were purely caused due to applying brakes.
In the same manner,over the past years more better technology was introduced:-
1.Brake Assist--Aids confused,old age drivers during braking by sensing the speed by which brake pedal is pressed and distributing that amount of pressure to wheels i.e Old age individual cannot press pedal forcefully but the braking system responds to his sudden pressing of the brake pedal and assumes an emergency and applies brakes forcefully----whole mechanism response is less than 2 seconds).
2.EBD(Electronic Brake Distribution)---Wheels rotation is being monitored and brake force to every wheel is applied according to rotation speed of each wheel on braking.During turning,the inner wheel rotation is lesser than the wheel rotation speed of outer wheel.This helps in better vehicle control and stability while applying brakes during cornering and at high speeds while in a curve.
3.VSC(Vehicle Stability Control) Or VTC(Vehicle Traction Control)---This helps the vehicle while driving by monitoring the wheel rotation and if any wheel individualy slips during driving,it automatically reduces power to the wheel and stabilizes it until slipping factor is neutralized.During hard acceleration,controls power transmission to the wheels in a way that the wheels should not slip.Same is for braking at higher speeds,it assists the ABS mechanism by helping in reducing engine output so that the wheels should not slip and vehicle can be manuvered easily.A vehicle hard braking with wheel lockup has greater braking distance than a vehicle without wheel lockup.Pickup of a vehicle while screeching is lesser than a vehicle with no screeching effect having same specs.
Basic Commonly Used Sedans In Pakistan:-
1.Baleno (Disc/Drum)
2.Liana Rxi(Disc/Drum) Lxi(Disc/Drum)ABS with brake assist
3.Honda exi(Disc/Disc) VTI(Disc/Disc)ABS
4.Toyota xli,gli,2.0D,Se-Saloon,2.0D saloon till may 2005(Disc/Disc) Altis,2.0d Saloon from June 2005(Disc/Disc)ABS with brake assist & EBD
