| Author |
Message |
Don Higday (Donaldh2o)
New member
Username: Donaldh2o
Post Number: 5
Registered: 10-2003
| | Posted on Thursday, October 16, 2003 - 1:11 am: | |
It's fixed! My guess is because I was bleeding the rear brakes (and replacing the brake fluid) with a MightyVac, a little hand pumper that pumps fluid from the bleeder valve, I had pumped much of the fluid out of the rear brake lines. Maybe the pressure delimiter valve was clogged with dirty particles and did not return to normal position. Anyway, when I began bleeding the rear lines with the traditional two-man method (actually one-man and a wife yelling, "My leg is so tired of pushing this damn peddle and I hate this car!"), the valve freed itself and returned to normal position. The "Brake Failure" light went off and is now operating correctly. Thanks guys and really appreciate all the help. The lesson learned is the traditional brake bleeding is obviously better than the MightyVac for bleeding brakes. |
dave handa (Davehanda)
Intermediate Member
Username: Davehanda
Post Number: 2052
Registered: 5-2001
| | Posted on Wednesday, October 15, 2003 - 7:32 pm: | |
Check this too: http://snurl.com/2ort
Dave |
Tom Jones (Ferrarioldman)
Junior Member
Username: Ferrarioldman
Post Number: 153
Registered: 6-2002
| | Posted on Wednesday, October 15, 2003 - 7:01 pm: | |
Look from under the front of your car and follow your brake lines from the master cylinder to a distribution block in which there is a pressure switch with one wire going to it. If you disconnect it and your warning light goes out then the problem lies there. That switch will pull out. Sometimes they get corroded or dirty and short out causing the light to come on. There is a little piston inside that dist. block and if it is pushed to one side as in a difference in pressure on one side of the block, then it grounds the contact of the switch causing the light to come on. It has to be either this or the float switches. Hope that this helps. |
Mike Procopio (Pupz308)
Member
Username: Pupz308
Post Number: 563
Registered: 10-2002
| | Posted on Tuesday, October 14, 2003 - 11:36 am: | |
I've had a lot of experience with this lately.
I've got a carbed 308, and I think the brake systems are pretty much the same.
There first question is, how does your brake pedal feel? Rock hard, or... a little spongy?
The issue is, on my 308 anyway, there are at least two things that can trigger the brake failure light. First, as you know, is that one of the two brake fluid reservoirs gets emptied and has a low level condition.
The second, though is if there is a major pressure differential between the left-front, right-rear circuit, and the right-front, left-rear circuit.
This pressure differential can happen if you get a large air bubble in either circuit, which is what would happen if you emptied one of the two reservoirs and just put fluid back in without rebleeding your brake system.
On the other hand, if your brake pedal feels strong, it's possible the little float-type sensor in one of the reservoirs did get "stuck" or otherwise failed.
I would suspect the relay the least...
Good news re: the brakes. I would be tickled if they were IDENTICAL (re: calipers and all), but my feeling is there are subtle differences...
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Don Higday (Donaldh2o)
New member
Username: Donaldh2o
Post Number: 1
Registered: 10-2003
| | Posted on Tuesday, October 14, 2003 - 10:48 am: | |
Just replaced brake pads and brake fluid on 1975 308 GT4 and the "Brake Failure" light is on. During the fluid change, I fired up the engine while one of the reservoirs was low and I think that triggered the light. Now both reservoirs are full and the light is still on. My guess is the sensor or the relay that turns the light on is stuck, but I don't know where either of these are located. BTW, the brakes on the 308 series are from 1972 Mercedes 280S and 300S series. Brake pads (Bendix D45 & D31) are available from everyone and cheap CarQuest, Kragen, etc. |
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