What do I need to replace if the shock absorber or the coil?? It seems to compress easily with the load of 5 to 6 passengers. I tried to replace the shock absorber with ordinary gas type but still with the same load the rear is very low and the shock absorber compress to maximum limit. what seems to be the problem.

The X5's and some 5 series models have a compressor in the boot which pump up the rear shock absorbers to level the rear of the vehicle when you load the boot or connect a heavy load on the tow bar, before going down the road of getting an expert to look at it have a look under the vehicle and you will see to black boxes one each near the shock absorbers and check the arm that comes off these two boxes they should both be at the same angle in relation to the black boxes if one is different then its causing the system to be out of alignment.

you have to compress the spring to remove the strut

They're easy to change - just compress, remove, compress, install - unless they're coil - over - shock, then the spring needs to be compressed (DANGEROUS) and removed as well.
If it's just loose, try replacing the shock tower mounts.

Please raise the car 3ft,remove front tire,remove the front steering lingkages.remove the 2 nut on the bolt of the shock absorber.remove the strut bolt of the wheel.get a special tools or coil spring compresser to compres the coil spring then remove the upper bolt of the shock absorber,replace the shock,replace the clock spring of the steering wheel.

REMOVE REAR SEAT AND PACKAGE SHELF TO GAIN ACCESS TO THE UPPER SHOCK ATTACHING NUTS.REMOVE UPPER ATTACHING NUTS. RAISE VECHICLE REMOVE REAR WHEEL AND SUPPORT THE LOWER CONTROL ARM WITH A JACK REMOVE LOWER SHOCK ABSORBER MOUNTING BOLT. REMOVE SHOCK ABSORBER ASSEMBLY FROM THE VECHICLE. COMPRESS THE COIL SPRING WITH THE PROPER SPRING COMPRESSOR TOOL. REMOVE CENTER RETAINING NUT HOLDING THE UPPER MOUNTING INSULATOR. SLOWLY DECOMPRESS THE COIL SPRING.REMOVE THE MOUNTING INSULATOR AND THE COIL SPRING. REMOVE THE COIL SPRING. TO INSTALL COMPRESSED COIL SPRING ONTO THE STRUT ASSEMBLY. BE SURE TO THE END OF THE SPRING IS IN THE NOTCH ON THE LOWER SEAT.INSTALL UPPER MOUNTING INSULATOR. YOU WILL NEW LOCKNUT FOR THE CENTER RETAINING NUT OF THE COIL SPRING. CENTER RETAINING NUT AND TORQUE THE NUT TO 13 TO 17 FT LBS. SLOWLY REMOVE THE SPRING COMPRESSOR TOOL. INSTALL SHOCK ABSORBER ASSEMBLY IN THE VECHICLE AND INSTALL THE MOUNTING FASTERNERS AND TORQUE LOWER MOUNTING BOLTS TO 72 - 87 FT LBS. INSTALL WHEEL.LOWER VECHICLE. WARNING COIL SPRING UNDER EXTREME LOADS WHEN COMPRESSED.BESURE TO PROPERLY ALIGN THE SPRING WITH THE COMPRESSING TOOL TO PREVENT PERSONAL INJURY FROM THE SPRING RELEASING UNEXPECTEDLY.

Rear coil springs are in need of replacement. They are the only components that give the vehicle its stance / leveling. Normal factory shocks simply dampen the ride and absorb road bumps.

THe 93 Mazda has both actually. The shock absorber in this car is just one component of the so called strut assembly. Read on if you want the details: Shock absorbers are simple suspension dampers that control the unwanted spring motion of the vehicle's frame caused by the suspension's springs. Struts, or strut assemblies, basically does the same thing, although they are used on a different type of suspension system and performs another function, which is to provide support for the suspension system.

A strut assembly is composed basically of a shock absorber unit, a coil spring, an upper pivot, and a lower control arm. A lot of vehicles today make use of strut assemblies instead of simple shock absorbers for the suspension system. The most popular of these strut assemblies is the MacPherson Strut for the front suspension and its rear suspension counterpart, the Chapman Strut.

Mazda vehicles are well known for their sporty looks and performance, amazing a lot of auto critics when they accelerate on paved streets and highways. Mazda vehicles, however, also has the capability of running on an off-road track without affecting the comfort that Mazda passengers feel; thanks a lot to the high quality Mazda struts they are equipped with. Original Mazda struts are guaranteed to provide every Mazda passenger a pleasurable ride, whatever kind of trail they may choose to traverse.

If you have the self-leveling Nivomat rear suspension system, you can replace your Nivomat shock absorbers with standard shock absorbers. You also have to replace the coil springs with standard coil springs. Please note that a combination of standard springs and Nivomat shock absorbers, or Nivomat compatible springs and standard shock absorbers, will not work.

If it is just the cost of springs that you are concerned about, try purchasing your springs elsewhere, and having your local mechanic install them. Two good sources online are; usautoparts.net and autopartswarehouse.com . You can find Nivomat compatible coil springs for less than $120 per pair.

Okay....here is the steps first....and then the directions on how to use the tools:

1. Raise and properly support the vehicle.
2. Remove the front wheel.
3. Detach the shock absorber lower mount by removing the two bolts.
4. Remove the retainer nut, retainer, cushion and shock absorber.
5. Detach the cushion retainer from the shock absorber.
6. Compress the coil spring with a commercially available spring compressor.
7. Detach the stabilizer bar.
8. Support the upper suspension arm and steering knuckle securely.
9. Remove the cotter pin.
10. Loosen and remove the nut.
11. Using a ball joint removal tool, detach the lower ball joint from the lower control arm.
12. Loosen the suspension arm set bolt.
13. Remove the suspension arm set bolt nut.
14. Remove the nut from the strut bar front set bolt.
15. Pull out both set bolts.
16. Remove the lower suspension arm and coil spring. To install:
    
17. Installation is the reverse of removal. Note the following torque specifications:
    1. Strut bar front set bolt: 221 ft. lbs. (300 Nm)
    2. Lower suspension arm set bolt: 148 ft. lbs. (200 Nm)
    3. Lower ball joint nut: 80 ft. lbs. (110 Nm)
    4. Lug nuts: 83 ft. lbs. (110 Nm).

Yes! If ya dont have a good spring compressor, and ya take the center nut out.. It'll kill you as the spring/shock separates.. My advice is to watch one being done before attempting.. Thanks