Brake reservoir question

[sdg3205]

What's everyone's favourite way to clean the brake fluid resovoire? I've got crud in some hard to reach places (ha) that ill need to take care of. I was thinking of an acetone bath.

Also, this little metal disk isn't listed on the DMCH website. Pretty rusted. Does this need to be replaced?

15753

[Cory W]

I covered the bottom hole with my hand and a rag, filled mine with brake cleaner, let it sit a few minutes, and shook the hell out of it. In my case, it worked. YMMV.

Somewhere along the way, I LOST that little metal disc. When I next called Dave and Julee, Dave advised it's a minimal issue, and not to worry (many cars come into Midwest without one in there). My car has stopped straight and true without it all last driving season.

[Mark D]

I struggled with cleaning out my brake fluid reservoir...I cleaned it a few times with brake cleaner but there was still a brown rusty film on the inside.

then I got smart and filled it with about 50 small stainless washers from my hardware stash. Plug the holes in the reservoir and spray in some more brake cleaner. Then shake for a few minutes. The washers are abrasive enough to clean the gunk and get into all the little nooks an crannies inside the reservoir. I'm sure there are lots of other things you could use besides washers, but that was what I had on hand and it worked great.

[sdg3205]

I hadn't thought about adding something like that. Good call!

[Tillsy]

What the hell does that red thing and the metal disc do anyway?

When I cleaned my reservoir out I intentionally left them both out as I couldn't for the life of me see the point in them...?!

[sdg3205]

IIRC, the red cylinder acts as a channel for the "brake" light sensor float. A vendor can maybe correct me on this.

[Tillsy]

IIRC, the red cylinder acts as a channel for the "brake" light sensor float. A vendor can maybe correct me on this.

That was my assumption too, except I figured the cylinder would create an artificial level as the tiny hole at the bottom can only vacate brake fluid AFTER the rest of the reservoir has emptied?

[WelmoedJ]

There are 2 small clips securing the reservoir to the master brake cylinder.
If you remove the clips, you can take the reservoir off.

Over here (Europe) we have use sand (coarse grain) to clean the inside.
Of course you have to make sure no sand remains after cleaning.

Be sure to put the seals back in place before re-installing the reservoir to the cylinder.

[Tillsy]

When I cleaned mine out I used a similar approach as others here - I'm pretty sure I used nothing more than dishwashing detergent, but added in a few nuts and bolts then shook the bejesus out of it... this removed all the hard crusty crap that was inside and gave me an almost brand new finish per the bottom part of this picture...
http://dmctalk.org/attachment.php?attachmentid=11614&d=1341411500

[DMCMW Dave]

That was my assumption too, except I figured the cylinder would create an artificial level as the tiny hole at the bottom can only vacate brake fluid AFTER the rest of the reservoir has emptied?

It's is to slow down the movement of the float so you don't get false "empty" warning lights as the fluid sloshes around.

The level in that small cylinder will matc the level of the whole reservoir over a short period of time. It will not stay full until the rest of the reservoir is empty, any more than a soda strw in a drink will stay full until the glass is empty.

[David T]

If the metal disc is all rusty you can assume the rest of the insides of your brake system looks about the same! It corrodes for the same reason, the brake fluid becomes corrosive because it was in too long and absorbed too much moisture. Any washer that fits will do. Should have a small hole in it, about 1/16". I wash the reservoir out with Alcohol and some long Q tips. All the disc does is to delay the filing and emptying of the chamber so that the float in it won't flash the brake light during acceleration, braking or on steep hills. No effect on the actual braking. If you EVER see the brake light on and you know the E Brake is not on, STOP THE CAR IMMEDIATELY! That is the ONLY warning you will get before you lose the service brakes! All you have now is the E-Brake and we all know how good that is! It is good for parking or if the car is rolling slowly. Try stopping the car at speed in an emergency with it. Even with all of the Adrenaline you will use pulling on it, it ain't gonna do much! BTW, if you make the mistake of putting the reservoir on the wrong way it hits the brake booster. Just flip it around. After you are all done you can test the level switch by pressing on the black rubber in the center. It should light the brake light. It is also supposed to light when the E-Brake is not ALL the way down (and off). I recommend you bench bleed the master cylinder before installing it back into the car.
David Teitelbaum

[sdg3205]

As always, thanks everyone for the tips and tricks!

[Tillsy]

It's is to slow down the movement of the float so you don't get false "empty" warning lights as the fluid sloshes around.

The level in that small cylinder will matc the level of the whole reservoir over a short period of time. It will not stay full until the rest of the reservoir is empty, any more than a soda strw in a drink will stay full until the glass is empty.

Cheers Dave - I'll refit it when I change all my fluid's mid-next year.