Fluid Won’t Cure What Ails Clutch
Question: I recently had to replace the master cylinder for the clutch on my 1987 Toyota Corolla FX. At the time, the car had only 15,000 miles on it, since I live only four blocks from my job. The problem was that I could not put the transmission in gear. How do I know that I really needed a $100 master cylinder rather than just the addition of some more fluid?--D.P.
Answer: Since the system is a closed loop, any loss of fluid means that you have a leak and therefore a malfunction. Adding fluid may have temporarily fixed the problem, but fluid would continue to leak and, probably, at an accelerated rate.
The entire hydraulic system is what connects your clutch pedal to the clutch, replacing older systems that used a simple cable. The hydraulic system has some mechanical advantages over a cable, but they can be quite a bit more expensive to repair, as you have discovered.
The failure in your system occurred much too soon to be the result of normal wear on the part. It most likely occurred because the fluid became contaminated with a substance that ruined the rubber seals and allowed a leak to occur.
A frequent culprit in such cases is motor oil that is added to brake fluid. This may have occurred in the factory, but it more likely happened during servicing.
Q: I recently paid several hundred dollars to replace the struts on my 1988 Nissan Sentra. What exactly are struts? Why did they fail with only 40,000 miles on the car?--A.T.
A: Struts perform the same job as shock absorbers, but they are called struts because they are integrated into the springs and suspension system on either the front or rear of the car.
The struts dampen road shocks. The strut’s main part is a piston that is restricted in its movement by oil that must be displaced by the piston, similar to the action of an old-fashioned butter churn.
The piston is connected to a rod that runs outside the strut through a rubber O-ring. This is typically where the strut fails, because once the O-ring allows oil to leak, the strut will no longer be capable of dampening road shocks.
When a mechanic inspects a strut, he often looks for signs of leaking oil, but the simple existence of some oil on the strut does not warrant its replacement. Rather, enough oil must have leaked to degrade the performance of the strut. There might, for example, be signs of wear on your tires. The car will bounce excessively in driving.
Struts often deteriorate slowly over a long period of time. When a mechanic advises replacement, ask him why he is making his recommendation. Ask if there are signs of uneven tire wear.
Struts often fail prematurely if they are exposed to harsh driving conditions, such as dusty roads, extreme cold and harsh surfaces. If you drive in a warm climate with good roads, struts can last quite long, even more than 100,000 miles.
