Brake Master Cylinder?

[fkong777]

I only drive my car about once a month. Now that it is summer I can drive it more. I just notice that my brake pedal at a stop light goes down slightly then it stops. then 5 second later it goes down slightly again. I popped open the brake reservoir and it is filled. but the ABS reservoir seems a little low.

Its a 91 NSX with 80K miles

Do I need a new Master Cylinder? or do I just need to do a flush?
Where is the best price for a Master Cylinder? Thanks.

 

[Larry Bastanza]

Definately flush first, it is inexpensive and may cure it.

If not, you can go to any discount dealer such as Ray Laks Acura 1-888-729-5257 ask for JR.

Brake Master Cylinder is:

46100-SL0-954 MASTER CYLINDER ASSY. $328.96 List

Check with them on pricing if you need one.

Regards,
LarryB

 

[quack]

The same thing happened to me. I have a 91 ~90k. I just installed one from Dali ~$250 not bad and it was OEM as well. Bleeding the brakes was a super pain.

Professor Quack.

 

[Bob_54]

It sounds to me like you have a master cylinder low pressure leakage issue. The typical causes are:
1) seal particles between the pressure seals and the master cylinder bore
2) seal lip wear
3) wear and/or scratch on the master cylinder bore

I would suggest flushing the system with new brake fluid first and see if the issue is resolved. If your brake fluid is dark and you see particles suspended in the master cylinder brake fluid reservoir I suspect cause #1 is your issue.

Another thing you may want to check before you buy a new master cylinder is the brake vacuum booster and vacuum line to the brake booster. Fluctuation of the vacuum level in the brake booster can also cause the brake pedal to drop.