Brake pedal goes to floor at a stop. Need help

[emvanderpol]

I've noticed over the past few months my '95 NSX brake pedal goes to the floor as if there is some type of leak in the system. If I lift off the brake it goes back up and will hold the pedal pressure for a brief moment and go back to the floor slowly. The brakes work fine otherwise.

Any help on fixing this would be greatly appreciated.

 

[CL65 Captain]

Check under the carpet behind the pedals.
Is it damp?
Are you loosing fluid?

Brake Master Cylinder leaking.

Try bleeding the brakes.... alot! 20x at each wheel. Check where the brake lines attach to each of the calipers and make sure it's not leaking.

Most likely though.... Brake Master

 

[emvanderpol]

Check under the carpet behind the pedals.
Is it damp?
Are you loosing fluid?

Brake Master Cylinder leaking.

Try bleeding the brakes.... alot! 20x at each wheel. Check where the brake lines attach to each of the calipers and make sure it's not leaking.

Most likely though.... Brake Master

I thought I was getting a leak somewhere too, but it's not. Reservoir level has not moved at all.

 

[CDX_NSX]

Sounds like a bad brake master cylinder. Fix is replacement (ASAP).

 

[Mark G]

I had the same problem.........as CDX_NSX said, you need a new master brake cylinder.

 

[pgilliam1]

"Ditto" on the Master cylinder. Mine did the same thing. It's a very easy DIY. Cost is about $200 for the master cylinder (I found one on eBay for $180). Be sure to bench bleed the master before install and then bleed the drivers front caliper first followed by the other front and then the rears. There's really no need to adjust the brake pedal as you can just reinsert the old piston into the new master. Replace the rubber grommet that is on the firewall, one should come with the new cylinder.

IF YOU DO NOT KNOW HOW TO BLEED THE FLUID IN YOUR BRAKES - DO NOT DO THIS JOB. NO BRAKES IS A REALLY BAD THING!

Good Luck!

 

[goldNSX]

Brake Master for sure.

I would not call it an easy DIY as it needs A LOT of bleeding until the brake pedal feels hard again. The only way the bleeding is doable is with a PowerBleeder kind of tool or air pressure. I've spent a lot of time trying to do that with the speed bleeders until I've found out.

 

[Larry Bastanza]

Check under the carpet behind the pedals.
Is it damp?

Just an FYI, above is the symptom of the CLUTCH master, not the brake. The brake master cylinder is attched to the brake booster, so the leak, if there, for the BRAKE master is in the front bay, not the interior.

To the OP, as everyuone menitoned sounds like you need a brake master cylinder.

Regards,
LarryB

 

[pgilliam1]

Brake Master for sure.

I would not call it an easy DIY as it needs A LOT of bleeding until the brake pedal feels hard again. The only way the bleeding is doable is with a PowerBleeder kind of tool or air pressure. I've spent a lot of time trying to do that with the speed bleeders until I've found out.

OR - If you have a friend/wife/son/daughter they can "pump up and hold" the brake pedal after you open and close the maintenance bleeders on your calipers :smile:.

Good Luck!

 

[goldNSX]

OR - If you have a friend/wife/son/daughter they can "pump up and hold" the brake pedal after you open and close the maintenance bleeders on your calipers :smile:.

Good Luck!

Ok, second best way. External air pressure bleeding is favored because if you press the pedal only you only compress the air within, near to none happens at first. Vaccum at the brake caliper is also doable but the stress is on that you need a external force if the master is full of air.

My experience is that if you change master and/or slave on the brakes/clutch with new parts it's a pain to bleed the hole system as small air bubbles in the edges within the new part won't get bleeded the first time. It needs several runs with acting the pedal in between until you have a very firm pedal.

 

[emvanderpol]

Thanks guys for all your help.

 

[ralph cerbone]

1st step ,go to auto parts store or on line and buy a MITY-VAC pump, it is a hand operated vacuum pump with many uses ,.install cyl.(bench bleeding is optional ) connect mity vac to each bleeder in correct sequence, ,( there is a bottle supplied in the kit just for bleeding brakes so you can watch the fluid come out ) pump a vacuum ,open bleeder until all bubbles disappear(have someone ready to add fluid as it goes down), tried the wife option just leads to other problems, :smile:

 

[VampNSXX]

same thing with my old Plelude and it was the master cylinder. get a new one befor the car just does not stop any more.

 

[Dhalsim]

well as everyone already told you its time for a new Brake MC. Just wanted to add that its very easy to install so if you have some simple tools and the time save yourself a few bucks and do it yourself.

 

[Hugh]

If you have a friend/wife/son/daughter they can "pump up and hold"

That is very disturbing. :biggrin: