928ntslow

The adventure continues with my Euro. The BREMSKREIS light.(which means Brake Circuit as far as I had found) is flashing along with the "!". I cannot turn these lights off.

I checked the brake lights and they work fine, the car stops fine, however, I do notice (even since I have had the car) that when I depress the brake pedal, there is kind of a hissing sound...vacuum I guess. The pedal is stiff as compared to what I would think it should be.

Any brake light warnings I had gotten before on 928's, have been pads or lights and those warnings can be canceled. This one just keeps on flashing and won't go away.

Anyone want to point me in the right direction for trouble shooting? Is it possibly the booster?

Bill Ball

Hissing? Firmer than usual pedal? ---> Brake booster leak.

Don't know how the Euro/OB warning system works.

Mrmerlin

check the E brake shut off swiitch, the master cylinder resivour lo fluid switch, see if you have the 2 warning light switches screwed into the master if you do then you may have to replace both of them, just a few quick thoughts

928ntslow

Both switches at master cylinder are brand new and I didn't have this problem before or after the switches were replaced. E-brake switch is fine.

Leon Speed

Some things I can think of:

- fluid resevoir switch faulty/dirty
- uneven pressure between master cylinder switches

RyanPerrella

Thanks Keith, i got my German word of the day in. I can check that off the list.

Mrmerlin

OK bleed the lines at the master, crack them open and see if airbubbles comes out

macreel

Try a bleed...
but stiffer pedal and hiss? booster leak; maybe loose venturi on intake(?)

Stay on I-84... don't need no brakes.

G'luck, Keith

928ntslow

I fail to see what a bleed will do. ...and Stan, what do you mean "crack them open"? I can bet you that opening up the lines at the master will certainly put air in there. Maybe you meant to say something else.

marton

I had the same problem & eventually replaced the Brake M/C which fixed it.
To switch off the light you have to disconnect the battery for 10+ seconds.

Could also be a fault in the central informer which lives under the LH foot rest-

Marton

Dennis Wilson

A hard pedal means the booster is not functioning. This would keep the master cylinder from making full travel on the piston and light up your warning light. A nonfunctioning booster can be caused by a leaking master allowing fluid to enter the booster and block the valves or there is a vacuum leaking on the booster circuit. Have you checked your brake fluid level?

Dennis

928ntslow

Brake fluid level is fine. This is an 82 ROW, so it is a K-Jet (not that that makes any difference) I don't think it is the central warning as nothing else seems to be acting up. However, I did have an incident where I would depress the brakes and the headlights went off....hmmmm

Any way to check the booster? Actually, when I depress the brake pedal, you can feel resistance and the pedal want to come back up. As I mentioned before, you can hear hissing.

nosnow

With the vacuum leak check to make sure the rubber seal/o-ring on the master cylinder is seated properly or if the vacuum leak is from that area. If the vacuum leak developed after the master cylinder change I would check this part before spending $$$$ on a new master vac. If it isn't that seal you'll probably need a new master vac.

My Brake Pressure warning light turned on after I replaced the master. I took the connectors off of the switchs and it looked like some brake fluid made it in there and caused a short. The only way to cancel this warning is to undo the battery negative ground.... maybe there is a simpler way but I couldn't find it. After I cleaned the contacts I've not had a problem.

Mrmerlin

By cracking the lines the resivour head pressure will force out air from the master if there is air in the master than you will see bubbles come out from around the hose connections, trust me here Keith . (unless your master has a bleeder at the end of it)
Otherwise a new master may be the remedy, as pressure may not be equal in the cylinder, when its activated

Dennis Wilson

Keith,

Think you can check for brake fluid in the booster by taking off the vacuum line and valve then use a pipe cleaner. Any fluid in the booster can interfere with the internal valve operation. Another possibilty is a leaking vacuum line grommet at the booster.

Dennis