Brake bleeding problem on modulator on 94
Thread Starter
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 207
From: Orlando FL
Brake bleeding problem on modulator on 94
I Have excessive brake pedal travels and poor braking and am targeting a bad master cylinder as probably the problem. However I thought I would first bleed everything to see if anything would change or improve. All wheels bleed normal with pedal dropping as I opened the respective bleed valve about a half turn. When I went to bleed the prime bleed valve on the modulator (behind driver), I got almost nothing coming out. Only a few drops and the pedal would not drop. I did this 3 times opening the bleed valve 2 to 3 turns which I thought should be enough. 
This is the first time I had ever tried to bleed the modulator and did not know what to expect but I didn’t expect this result. I will next remove the bleed screw to see if it is clogged but sitting in a protective area with a cap on it, I wouldn’t think dirt would get in there – just ran out of time last night. I would expect this process to be same as doing a wheel cylinder bleeding. Any thoughts, have I missed or don’t know something, no special direction in red book.
This is the first time I had ever tried to bleed the modulator and did not know what to expect but I didn’t expect this result. I will next remove the bleed screw to see if it is clogged but sitting in a protective area with a cap on it, I wouldn’t think dirt would get in there – just ran out of time last night. I would expect this process to be same as doing a wheel cylinder bleeding. Any thoughts, have I missed or don’t know something, no special direction in red book.
Race Director
Joined: Oct 2000
Posts: 14,064
Likes: 1,166
From: N. Alabama
Not sure about the procedure on the modulator as I have never done that before but I do understand that one has to have the dealer plug in the tech9 (?) scanner to make the modulator valves open in order to bleed them. This may be the problem but, as I say, I have never done this. I only responded to your post since there were no others and this might be the avenue you need to pursue. Sorry I can't be more helpful..
