What? No brake m/c reservoir cap!

[frisbeeguy]

Ok, just want y'all to help me out here. Yesterday, as my stepson was redoing his thumper audio system, I happened to notice there was no cap on the master cylinder reservoir! He attempted to shrug it off as no big deal, don't know where it was, gone for a week!
I informed him he would know very quickly the cap was missing.
Could y'all confirm for me (him) the pedal would goto the floor and fluid would spill out as soon as he went to drive w/o it. Thanks.
($13 for the cap and gasket! & 2 trips to the store)

 

[Number4]

Fluid could certainly come out. Brake fluid will destroy paint. If dirt gets in you will eventually have issues. Same with moisture. It's just a reservoir though, don't know that the pedal would have any issues.

 

[D Hook]

Fluid might come out from being sloshed around with the cap off and spill onto components that will then rust or deteriorate. But the fluid will not be forced out of the reservoir when pushing on the brake pedal.

$13 for cap/gasket is nothing compared to the cost of fixing all the things that will go wrong by not replacing it. Getting moisture into the brake fluid would be the first concern. That could easily lead to loss of braking power. Cost of getting all the fluid bled out and replaced will easily exceed the cost of the cap.

 

[frisbeeguy]

Thanks for the replies guys. I guess there is some one way valve prevènting the fluid from coming out when braking?
I understand the problems with dirt & moisture getting into the system... Was hoping for someone to post some alarming warning about the potential danger & damage from just ignoring the missing cap.

 

[Number4]

Thanks for the replies guys. I guess there is some one way valve prevènting the fluid from coming out when braking?
I understand the problems with dirt & moisture getting into the system... Was hoping for someone to post some alarming warning about the potential danger & damage from just ignoring the missing cap.

Brake fluid (non silicone/dot 5) absorbs water. Brake fluid has a high boiling temp, which stands up to the heat the brakes generate, without turning into vapor. Brake fluid that has absorbed to much moisture will then have a lower boiling point. If it vaporizes, it will compress. Which could mean a loss of braking ability.

I'd say not getting into a wreck is worth $13.

 

[Mr Dubya]

The cap's sole purpose is to keep fluid from splashing out, and dirt/excess-moisture from getting in.

-Dubya

 

[frisbeeguy]

The cap's sole purpose is to keep fluid from splashing out, and dirt/excess-moisture from getting in.

-Dubya

These things didn't really matter, it seems. (But the touch screen, amp & woofers did)

Have the car back now... inspection expired 9 months ago. brake light on, fluid low, side view mirror taped on, rear bumper cover torn in 1/2 with a couple wood screws holding it in place, foglight busted & mis matched tires and the filthiest interior ever!

Replaced the brake fluid resevior (and found the lost cap in the process) the lip was broken preventing the cap from sealing. Bled in all new fluid afterwards.
Found a wrong color & very faded bumper cover... painted it (not matching but closest oreillys had) & popped it on.
cleaned, scrubbed & vacuumed
replaced air filter & cleaned maf sensor

Today got new stickers & it's legal to drive again! Yay

Haven't found a replacement fog light yet... going to post in wtb.

Thanks for the help y'all!