The master cylinder is a critical component of your brake system. Should a master cylinder fail, we have a safety problem that is even more compounded if you are driving a classic car with a single reservoir master cylinder. In addition to our own safety, we also endanger the drivers sharing the road with us. This post offers a brief description of how the master cylinder works, explains why the unit may fail, and offers some answers to commonly asked questions.
The master cylinder converts non-hydraulic pressure generated by your foot into hydraulic pressure by storing and delivering brake fluid to the brake calipers to slow or stop the car. A master cylinder has external and internal seals. Over time, when these seals break down, fluid can leak out of the unit, or leak past the inner seals instead of routing brake fluid to the calipers. If your master cylinder is going bad, you’ll likely feel a spongy pedal when you apply the brakes, or the pedal will drop to the floor while holding the car at a complete stop.
In our tech area, you’ll find our Master Cylinder FAQ answering common questions from classic car owners. In addition to answering typical questions (e.g., why do I have a hard/soft pedal, how can I tell if my master is failing?), the FAQ gives answers to questions associated with classic and vintage rides, including:
- What will happen if I use a master cylinder for drum brakes and it doesn't have a residual valve?
- What bore size do I need for manual brakes?
- What is the difference between a power brake master and a manual brake master?
- Can I use a shallow hole master cylinder in a manual brake application?
Can I use my manual master on a booster?
- Can I use a power brake master without a booster?
- Why is one fluid chamber larger than the other in a disc/drum master?
- Can I use a disc/drum master for four wheel disc brakes?
- How can I tell if my master cylinder is bad?
Why should I upgrade my single piston master?
- Should I buy a rebuilt or new master?
- Can I rebuild my master cylinder myself?
- My replacement master cylinder does not look like the original. Can I use it?
After you have read through the FAQ, you may determine your current master needs replacing. This is never the news an owner wants to hear, but remember, a properly operating master cylinder is needed to bring your vehicle to a safe stop. Parts for older makes and models can be hard to find, but we can set you up. Feel free to browse our website to check out master cylinders for classic cars, send us an email or give us a call at 1-800-381-9772 and we’ll get you back up and running in record time.