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Old/weak brake system, need to replace master cylinder?

Hi All

I have a 2002 Accord with about 130k miles on it and the brakes don’t have nearly the power that they used to. The pads and rotors are due for replacement but even then, the system is pretty weak. Would replacing the master cylinder help with this? What about simply replacing the brake fluid (I doubt it has ever been changed)? And/or the calipers? The car is in great condition and I really like it so I don’t mind investing some time and money to get more years out of it.


Take your Honda to a good, independent mechanic. When they replace the pads and rotors…have them inspect the entire braking system. A weak braking system is dangerous for you and the motoring public as well.

@missileman Right, don’t take a chance with brake systems.

A well-known chain has “packages”, from basic shoes and pads to a complete sytsem. The problem with this is that these shops can seldom really diagnose correctly what you really need. Even the full treatment may not solve your problem.That’s why an independent shop does the best job.

If the pedal slowly goes to the floor you could have a bad master cylinder or air in the lines, or a slow leak at the wheels.

In any case don’t drive the car any further than you have to.

Good luck!

Millileman and Doc have given you good advice.
In light of the car’s age, I’d suggest also getting the brake fluid flushed with fresh fluid, as you mentioned.

In addition tot he above good advice, I will say from experience with Honda’s that you probably don’t need a new master cylinder at this time, but as stated, you should get an opinion form a competent mechanic who has eyes on the system.

You do need OEM equivalent pads and a brake flush. The pads do not need to come from a Honda dealer, Honda does not manufacture brake pads anyway, but the pads that you use must meet the OEM specs. BTW the pads from the dealer cost about the same as any other pads that meet the OEM specs so you won’t be wasting money if you do buy from them. I also like Wagner Thermoquite Ceramic OEM pads. Don’t fall for “heavy duty” or “high performance” pads.

If the mechanic recommends new rotors, be sure they are high quality OEM spec rotors as well.

Perhaps what is “weak” is the vacuum power booster…This would be the FIRST place to look for problems…

All good advice above. I’ll also suggest that your rear brake shoes may be out of adjustment. I’d be willing to bet if someone puts this car up in the air and takes 5 minutes to adjust the rear shoes properly, this car will stop the way its supposed to.

I’ll put my money on the new pads and rotors making it stop properly.

By the way, the booster is super easy to check. Simply pump the brakes with the engine off to purge the vacuum in the canister, then start the engine while pressing on the brakes. The brake pedal should get hard with the original pumping, and sink and get softer when you start the engine.

Not to butt in on this one but thanks TSM. I’ve been wondering about the booster on my car that just sits all the time. Didn’t know it was that easy to check. Next time I run it I’ll check it.

You’re welcome.

Been There, Done That.
Another Situation Can Cause “Weak” Brakes (More Pedal Pressure Required For Inadequate Results).

If calipers cannot move laterally on their slides/pins then they apply braking pressure mainly through the piston-side pad instead of the pressure being more equal between the inboard and outboard pads.

I live in a rust-belt area and I’ve experienced this myself. Some cars, by design, have a bigger problem with calipers and corroded slides/pins than others. I don’t have as much trouble with all My GM cars, as they have stainless steel covers on the sliding portion of the caliper carriers.

My Chyrsler vehicles don’t have this feature (they’re iron on iron) and are more likely to develop “weak brakes,” especially if they’re parked for a period of days/weeks.

An indication that this is taking place is that the piston-side pads will wear much faster than the pads that are fixed to the calipers.

One needs to spend time thoroughly cleaning all brake components and applying grease water-resitant, heat-resistant greas, liberally, when doing brakes. Also, new pins and whatever other hardware needed should be used.