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Changing 9-5 brake fluid (the proceedure is similar for the NG900, 9000 & 9-3)

Brake fluid is hygroscopic, which is to say that it absorbs moisture from the atmosphere over time. This trait has two notable consequences: firstly, water in cylinders can cause them to deteriorate (rust) but secondly, water content over 3% causes the brakes to become ineffective or at least less effective if they are used more than usual, say, on a long descent downhill. Rust within hydraulic cylinders is bad news because the particles score cylinder walls or even shred rubber seals. 

Water content within the brake fluid has the effect of lowering the boiling point and the fluid loses the ability to transmit effort to activate the brake. The boiling boint of the fluid MUST be over 155° C for correct and safe braking. Dealers have a tester that checks the quality of the brake fluid but for owners there are two FREE tests:

  • If you don't know when the fluid was last changed, it should be changed
  • If the fluid LOOKS dirty, it should be changed

Tools, bleed order and fluid spec for SAAB 9-5 brake fluid change


Tools required:

  • Pressure bleeding kit (SAAB dealerships use a vacuum bleeding kit)
  • Socket and spanner set (MUST have 9mm ring spanner/socket for bleed nipples)
  • Suitable container for waste fluid

Parts & materials:

Suitable container for fresh fluid
Suitable receptacle for catching waste (old) fluid
DOT 4 brake fluid - it is better to use SMALLER containers because the fluid deteriorates upon exposure to air.


Special precautions:

WARNING! Health & Safety are terms that attract a fair bit of stick in the press BUT please read the next few lines! Brake fluid needs careful handling: it is toxic to humans and animals and will also damage car bodywork upon contact.  Worse still, it is highly combustible due to its low flashpoint. This means that if the fluid is inadvertently exposed to hot surfaces, it can catch fire. In short, NO smoking while doing the job and take care with lead lamps.

  • DON'T mix different types or ratings of brake fluid
  • ALWAYS use FRESH fluid from SEALED containers
  • NEVER be tempted to use that old half full container that's been on the garage shelf for the last 6 months

Finally, please don’t work on the brake system unless you are confident in your own abilities and have carried out similar procedures in the past.


Method

The car needs to be raised (either with a jack and secured on axle stands OR on ramps)but there is no need to remove the road wheels. Start by siphoning out some of the fluid from the brake reservoir without completely draining the tank, then replenish with fresh fluid. Take care not to spill fluid that might damage the paintwork.

Pressure or vacuum bleeding equipment is essential for this job

Start with the FRONT left wheel. Remove the rubber dust cover from the caliper bleed nipple and check –visually- the state of the bleed nipple. We usually wire brush the nipple and apply penetrating oil if we have doubts about the condition. Open the bleed nipple using the bleeding kit, keep bleeding the circuit until the fluid starts to run clear, then nip the nipple, remove the kit, top up the master cylinder reservoir and test that the pedal still works OK.

You don't need to take the wheels off to bleed the brakes, so long as the car is raised sufficiently

So long as the fluid in the tank has not been allowed to drop so low that it has sucked in air, there should be little risk of losing the pedal. By checking the pedal after bleeding each corner of the car, if a fault does develop, it is easy to work out where the problem lies.

After bleeding the front brake, head to the opposite corner (RIGHT hand rear) of the car and repeat the bleeding operation until you see clean fluid. Take care not to let the reservoir run dry. The 9-5 uses diagonally split, dual circuit brakes to ensure at least 50% brake effort even in the event of one circuit developing a major fault. So, Note that this operation will take rather more time than the previous one because the brake line is much longer.

Access to the rear brake nipples is good

Top up the reservoir and check the brake pedal still feels nice and firm before moving on to the RIGHT hand front wheel. Repeat the bleeding operation, then check and if necessary top up the reservoir before checking the brake pedal feels firm. Finally, bleed the remaining REAR brake, tighten the nipple and top up the reservoir before checking the brake pedal feels firm.

As a rule, you will find that problems are more likely to affect the rear brakes than the front. In the event of the brake pedal going spongy, repeat the bleeding operation again.

Complete the job by checking all bleed nipples are tight and that there are no leaks. Tidy up the work area and dispose of the old fluid.

Fluid as dirty as this should be changed


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