Reflush worked. Back to normal. I used the wet method this time. I'm going to stick to the wet method from now on.

Another consideration for the wet method is that it provides constant pressure of the lines. ie if you are flushing a bubble of air out of the master cylinder or line, if you stop while the bubble is in the brake line to refill, using the dry method, that bubble can move along the brake line (potentially away from the exit valve) when there is no pressure in the circuit.

Happy to be back to normal.

 

I have done a half dozen brake bleeds using the Motive bleeder without any difficulties. I replaced the factory brake lines on my 2008 911S and bled the brakes without issues. I recently replaced the brake lines on my 2012 997.2S and have the dreaded mushy brake pedal. My guess is that somehow I introduced air into the system. It may have been that I used my old Motive and the fluid was low enough that it wasn't able to be picked up by the small tube which pushed some air into the system. I purchased a new Blake Label bleeder and two of the Motive bleeder bottles. After bleeding with no bubbles and plenty of fluid in the Motive, the same problem. The brake fluid has probably been replaced at least three times in the last week in the continuing saga. I did learn that it is easy to bleed the brakes without removing the wheels. Driving through the Sierras next Wednesday with mushy brakes didn't sound like fun so the car is now at the dealer. It will be interesting to find out what the issue was. I also asked about bleeding the clutch fluid. Fortunately, I have two additional liters of Pentosin Super DOT 4 that they will use instead of the over-priced Porsche fluid. Will report back...

 

If you did end up introducing air into the system, not only will you need to bleed the clutch slave, but will also need to bleed the abs system using the actuate command for each wheel with a Durametric. I made that same mistake once and it took me 3 addt'l bottles of brake fluid to resolve the issue.

 

Thanks. It feels a little better knowing that I am not the first... The dealer will be able to make the necessary repairs with the ridiculously expensive equipment that will trigger the ABS. As I understand, there is a newer process for bleeding the clutch on the 997.2 and it requires a special tool. Fortunately, the clutch seems to be working normally. Another lesson learned. The new Black Label bleeder is terrific. Much easier to use with longer lines and a much better metal cap. Even so, it wouldn't hold a steady pressure and I noticed that the gauge had a crack in the lens. I called Motive and they were very helpful and quickly offered to send me another gauge. The long line that screws together was the culprit. They suggested teflon tape which was the right solution. In addition, the bleeder bottles are very handy and make the process much easier.

 

Only time I've ever used the Motive "wet" was last weekend... and the hose junction failed at 20psi. Spewed pressurized brake fluid all over the vehicle and garage while I was at the far corner. Happily, this was the X5 and not the 911.

Never again, going back to vacuum bleeding.

 

I've always used the dry method with the motive bleeder with no issue. I recently replaced an entire brake system on a 997- every single part except the hard brake lines was out of the car.

One trick if you're replacing lines to the caliper is to remove the caliper from the wheel and zip tie it to the top of the wheel well. Then bleed in this position.This allows the air bubbles to freely travel upward. Otherwise there's a loop in the brake hose that can hold a bubble.

 

Took my 2012 Carrera S back to the dealer this morning. They bled the brakes last week and they did improve some but I am still not satisfied. (I had replaced the factory brake lines with Goodridge stainless steel and managed to get air in the brake lines after using the Motive bleeder.) The brake pedal moves several inches before becoming effective. Am I being obsessive/compulsive...? I asked to have their shop foreman take a look at the brakes this time. The dealer has been excellent so far and I expect them to continue.

 

Based on your previous experience with the car and its brakes, if it feels different now, then there's still air somewhere in the line that I think needs to be bled out, either in the clutch slave cylinder or in the braking system itself (lines, calipers, etc).

 

Hi Pete,

The clutch feels exactly the same as it did before I introduced air into the system. Therefore, it's probably air lurking somewhere in the brake lines and/or ABS system. Fingers crossed...

 

This. I also use my Motiv as a pressure source (dry), out of fear that the line will blow and eat my paint. I accidentally ran it dry on my last bleed, but was able to re-bleed with my wife pumping the pedal and easily got all of the air out.

I use usually use < 1 litre of DOT4 to bleed all 4 corners.

 

I have used the "pump the pedal", "vacuum method with the hand pump" and most recently hooking up an air compressor to the top of the master cylinder. I am hoping the air compressor method works successfully.
Question: My pedal requires a pump or two to get solid, could my master be weak or is there still air in the system.
Thanks

 

A couple pumps to firm up is normal, when it gradually falls to the floor is when you have a problem. Best way to avoid issues dry bleeding is to measure the fluid coming out, either buy a marked bottle or put measure lines yourself. The reservoir holds ~ 8 oz, so refill when you’ve drained 6 or so. 24oz or so total, progressively less for each of the 8 bleeding points.

 

I hate to admit, but I am changing the brake fluid for maybe the first time in my "auto repair career", about 50 years. The 1975 914 is a former West coast car and very clean. The former owner took things apart several years ago and I bought a roller mostly in boxes. The brake fluid as coming out is "dirty" and am planning to run enough through until it comes clean.

Thanks for the reply, and after a pump or two the pedal stays firm. This probably equates to air in the system.

 

I attached the Porsche-procedure for bleeding brakes with ABS-module.