Rear end leak (not brake fluid)

If brake fluid, have to check caliper/caliper brake line or check brake wheel cylinder, where applicable.
Where applicable, if rear end oil, have to check seal and axle bearing.

Make sure the master cylinder is full and that the vacuum line going to it is is secure wit no air leaks. If as you state the brakes not being applied only at the drivers front and passengers rear wheels, but the other two wheels are working fine you will either have a leaking/blocked master cylinder, leaking/blocked brake lines feeding each of those wheels, or a bad proportioning valve. To trouble shoot raise the bad wheel and crack open the bleeder valve, have an assistant apply the brakes if a nice clean steady stream of fluid comes out, MC is OK, and valve is OK, any bubbles of poor flow indicates leak in system. Very little flow bad MC or blocked lines/valve, etc.Do the same for the rear wheel and you should be able to determine the fault.

this is a front wheel drive car there fore there is no rear end like a rear wheel drive. the fluid leak at the wheels is probably brake wheel cylinder/caliper or brake flex hose. check brake fluid level if its down then check for brake fluid leak if not then you will have to check the rear area for some other fluid leak.

No. Don't drive it at all. It is not safe. It is most likely the caliper and requires replacement.

The greasy one has a seal leaking between the backing plate and the brakes (axle seal) which in turn will cause your brakes to grab on that wheel when you apply the brakes. Remove the axle and replace the seal. Then thoroughly clean the brake shoes and backing plate until they appear bone-dry like the other side. This should solve your problem. Make sure the rear-end grease level is full when you finish.

In this case, you will need to leak the for wheels, never leak only one or two wheels when adjusting the breaks. If the leaking continues you need to check the conduit for potential damages. If pedal stay soft after checking everything else, check the break fluid unit. The unit has a piston if I'm not wrong. The piston has some parts that are of rubber material which can wear out or get damaged.

if you have drum brakes on the rear of the car and the leak is at the back of the car the part is called a wheel cylinder if the leak is coming from inside the brake drum.

usually an indicator of either a loss of pressure due to low fluid and/or air in the system (brake fluid leak) or extremely worn rear brakes (if drum brakes in rear). possible causes include master cylinder (internal fluid pressure leak), external fluid leaks (calipers, lines, wheel cylinders), rear drum brakes extremely worn down or severely out of adjustment. normally worn disc brakes may reduce pedal height SOME, but seldom "to floor". but the "mushy" quote combined with the "floor" quote suggests a hydrolic fluid pressure problem.

Your problem would appear to be something amiss in the rear brake on the locked wheel. If a wheel sylinder was leaking the brake shoes would become "sticky" and cause the shoes to "lock on" to the drum. Or if the brake was out of adjustment, the assembly could come apart and pieces of it jamb the wheel. This problem is fairly common with drum brakes. You need to have the rear brakes serviced, & checked for fluid or grease on the braking surfaces. All leaks fixed, backing plates cleaned, the wheel cylinders overhauled, & the brake shoes replaced.

ok there should be a square inlet on the end of the line you probably have to replace the gasket on it or poibly simply tighten it