Brake fluid smoke

[Bob G MN]

I noticed some smoke when I start the engine emitting from the exaust.  I also noticed the brake fluid is down a little bit over the past month.  Is it possible the fluid is getting into the engine and does anyone know the fix for this. I'm thinking it is a new master cylinder but is it possible the brake booster needs replacing.

Bob

[waqas]

If it were brake fluid, wouldn't the exhaust emit smoke at all times?

Check the little white plastic fluid trap container that sits along the vacuum hose that connects the booster to the intake manifold. (via the check valve). If you're getting brake fluid in your intake, then this container should also have something.

If this is indeed the case, you need to renew the master cylinder seals. (or replace entirely).  Brake fluid can damage the rubber diaphragm inside the booster, but if your revs stay the same whenever you press the brakes, your booster should still be good. Make sure you drain the booster and dry it out before reinstallation.

[hands_aus]

have the brake pads worn so that the fluid level has dropped?

[Bob G MN]

Thanks Wagas and Hans for the responces. I did notice a couple of drops of brake fluid in the plastic trap but very little and the trap hasn't been checked for over 20 years.  But the RPMs also rise when I apply the brake and I need to use quite a bit of pressure to stop the car.  The brake pads seem ok and they were replaces about 10,000 miles ago.
How difficult is it to replace the booster and master cylinder.  It relatively simple if it's just a matter of taking out the old and putting in new but as I have read several postings it seems that bleeding the brakes requires some equiptment I dont have. What's the process for draining out and drying the Booster?  it seems to be a sealed unit. Any other things that create a problem in accomplishing this.  If so I will probably take it to a mechanic.

THS,

Bob

[glennard]

Besides the booster leak--Seems the idle is rich.  Disconnect the vertical rod off the FI pump.  Slowly open the butterfly.  RPMs should rise 50(throttle barely open), then stall the engine with too much air.

[waqas]

quote:Originally posted by Bob G MN

But the RPMs also rise when I apply the brake and I need to use quite a bit of pressure to stop the car.

Your booster is done for. Get it rebuilt or replace it with a new unit. I used Power Brake Exchange in California to rebuild mine a few years ago for less than $200. (new is > $500)

I was told by the rebuilders that these boosters only go bad with age or brake fluid in the booster.

In your case, the likeliest source of failure is brake fluid in the booster. This means you need to either rebuild or replace your master cylinder with a new unit. (I'm starting to sound like a broken record)

Replacement is as easy as:
(1) drain brake fluid from system
(2) disconnect and remove master and booster
(3) install new master and booster
(4) new brake fluid and bleed

You may need to bench bleed the master cylinder prior to installation. For this, get a pressure bleeder (relatively cheap, especially if you build your own-- search the site for a link to DIY instructions).

[jacovdw]

Just for the record, here is that link Waqas was referring to with regards to that easy DIY brake bleeder:

http://www.bmw-m.net/TechProc/bleeder.htm