brake fluid leaking from bottom of reservoir?

[TheArtofEuros]

hello, i'm a new e30 owner and was just curious to know if a brake fluid leak from the bottom of the reservoir was common? i did some research and it looks like there are 2 grommets that slide onto the reservoir and into the master cylinder.

i bought the car, PO said there were no leaks...i noticed the next morning there was a small wet spot on my driveway. so i check fluids, all are fine. days goes by and i have the same small wet spot under my car right where the brake fluid reservoir is.

i topped off the brake fluid yesterday morning and the small wet spot turned into a small puddle and i noticed my brake fluid level was between max and min...my brake fluid reservoir is kind of loose almost as if the grommets are beat. i noticed there was a decent amount of brake fluid right where the reservoir meets the master cylinder.

is this a common problem? or are the grommets something that should be replaced after a certain amount of miles? judging from the way my upper rad hose looks (could be original) my bet is the grommets were never replaced.

here's the car.




thanks in advance, i love this car!

[ssaylor]

I had a similar problem with my washer reservoir. The rubber grommets get hard, dry out and no longer make a seal. The brake fluid reservoir has the same setup, Check #2 and#3 here.
http://www.realoem.com/bmw/showparts...21&hg=34&fg=25
It could be your master cylinder but you could be getting some funny brake action. I recommend you check these first.

[jlevie]

That could be the grommets, reservoir, or on a car with a manual transmission the fluid line to the clutch master cylinder.

[TheArtofEuros]

I had a similar problem with my washer reservoir. The rubber grommets get hard, dry out and no longer make a seal. The brake fluid reservoir has the same setup, Check #2 and#3 here.
http://www.realoem.com/bmw/showparts...21&hg=34&fg=25
It could be your master cylinder but you could be getting some funny brake action. I recommend you check these first.

yes this is what i found when i did some research. i'll be ordering the grommets today. process of elimination i guess. i hope its just the grommets.

That could be the grommets, reservoir, or on a car with a manual transmission the fluid line to the clutch master cylinder.

the car is an auto, thanks for the input!

on another note, valvoline makes this dot 3 & dot 4 brake fluid. says its meant to be used for cars that either. is this safe to use in the car temporarily until i can bleed the system and use actual bmw dot 4 fluid?

[jlevie]

Valvoline synthetic is is a DOT 4 fluid and is okay to use in place of BMW fluid.

[TheArtofEuros]

jlevie, thanks for the input. the brake fluid bottle says "dot 3 & dot 4". not sure if you were thinking i was talking about 2 different bottles.

[jlevie]

Valvoline Synthetic brake fluid is marked as being compatible with DOT 3 & 4, but it is a DOT 4 fluid.

[TheArtofEuros]

awesome! thanks for clearing that up.

[immajackuup]

dot 4 have a higher boiling point than dot 3.

[TheArtofEuros]

i knew the difference between 3 & 4, i just never saw them together. thanks!

[Huff]

By the way, make sure you don't get brake fluid on your new grommets (Try your very best at least) when installing them..

[TheArtofEuros]

thanks for the heads up. i plan on sucking all the fluid in the reservoir out with a turkey baster before i pull the reservoir from the master cylinder...dumb question, but won't the grommets get fluid on the anyway?

[Huff]

When you pull the reservoir, you'll see that the grommets only meet with the bottom of fluid (and that only partially). If you get elsewhere, the brake fluid will disolve them. Remember, brake fluid is extremely caustic...

I know this because a few years back I thought the same thing as you.. And one day brake fluid starting pouring out of my master cylinder a month after replacing those grommets. When I put my news in, they got some brake fluid splattered around them. Ate them up in a month.

[TheArtofEuros]

^ good to know...thanks for the heads up. the grommets are on the way!

[325isdan]

Can someone confirm if you need to bleed the system after you replace the grommets?