jwrape

When I brake fast and hard the brakes work great. Stop on a dime.

When I brake slowly to a slow stop, the pedal starts to bleed down to the floor and I have to pump it again to get my brakes back.
Is my Master cylinder going or do I just need to change and flush the fluid?

Personally is sounds like the MC is going to me...
What do you guys think?

mr.beeks

you got air!!!
in your brake system so flush and bleed brake system...

jwrape

Hmmm, I wonder how that would have happened. The brakes are great most of the time except when I gently come to a stop and they bleed down.
I will give that a try when I put liquid sealant on my TB to stop the whistling. :-)

Thanks for the suggestion

mike-y

Master Cylinder is on its way out. I've had this problem before (and so have a few friends). seemed to be worse on hot days or if I was stuck in traffic for a while.

replace with a new or rebuilt one and all is good.

pnoipj89

ya i agree with mike-y for that it is your master... bc if it was air in your system...it will go to the floor any type of braking, weather it is fast or slow? air would do that...but what your asking is your master is going

jwrape

Yea, I tend to agree with the Master cylinder theory. The brakes are solid when braking hard but bleed down under light braking. I think a seal is bleeding brake fluid past and the MC needs to be replaced.
Either way, if i replace the MC I will have to bleed the brakes anyways and I will also not have to worry about the MC again for as long as I own the car.

pnoipj89

yea....mr beeks over there sounded mad confident..hhaha

mr.beeks

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pnoipj89 &raquo;</TD></TR><TR><TD CLASS="quote">yea....mr beeks over there sounded mad confident..hhaha</TD></TR></TABLE>

always confident....
dont forget that brake fluid also wears down and a lot of people over look it.
so now that it has moisture in the fluid and other debri it will slowly wear out parts example brake cylinder.
have you ever taken a master cylinder apart?

is just like a medical ceringe a piston with one or two ring seals and eventually they will wear out, causing air to leak into the system and also not maintaining pressure.
if the master cylinder is just loosing pressure is just as simple to bleed the system.
if the master cylinder is leaking near the booster or at the pedal thats when I will change it.

mike-y

in this case, bleeding the system won't stop fluid from getting past the seals inside the mc (which are worn). Air in the system would produce a soft/sinking pedal 100% of the time (which isn't the case here).

This exact thing happened on two of my cars, and I would bleed fluid on the race car before every single track event, so I knew it wasn't that.

jwrape

Yea, it was doing it everytime last night on the way home in stop and go traffic, then by the time I got home it had started working fine again and this morning it was fine as well. Definately the MC. Gonna try to pick one up in a day or so.

allmotorek8

iTrader: (3)

does it matter if u get a used one or just get a new one?

jwrape

No, I just need one.

mike-y

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allmotorek8 &raquo;</TD></TR><TR><TD CLASS="quote">does it matter if u get a used one or just get a new one?</TD></TR></TABLE>

"used" is okay if its a rebuilt one from autozone/kragen/pep boys, etc.

maacoreds13

dont' wait too long...you don't want to be there if the thing totally fails