I removed my front caliper to replace the disk and when I try to bleed the system the brake pedal won't build up any pressure at all and I'm not getting anything out of the top or bottom bleeder on the caliper.

Could the MC have failed? Brakes had a firm pedal before my "repair", now nothing at all. Seems like to much of a coincidence for the MC to quit, but I can't think how air in the line could make the system so inorperable.

What to do?

My first advice would be "keep bleeding" it can take a while before it gets there. Do you have it topped off in fluid? Bleed the entire system.

If the MC has failed you'll probably see fluid in your pedal assembly.

You can try another caliper to see if you get fluid when you vent it. If no fluid then the m/c is probably toast. If you get fluid then it could be air. Did you spread the pistons when you put on the new rotor? If so then the seals will have to reseat and it can take a while.

Did you put the caliper back on the car?? I noticed you said you removed it but you didnt say anything about putting it back on.

QUOTE (john rogers @ Mar 28 2005, 05:07 PM)

You can try another caliper to see if you get fluid when you vent it. If no fluid then the m/c is probably toast. If you get fluid then it could be air. Did you spread the pistons when you put on the new rotor? If so then the seals will have to reseat and it can take a while.

I started at the rear brake, and was getting fluid there so my first thought was that it couldn't be the master cylinder, but I've done the bleeding cycle (pump, hold, open bleed valve, shut bleed valve, release) on the front caliper which i removed AND re-installed(in case you're wondering) maybe 20 times and there is still no pedal. Strange thing is it pumped some fluid from the front to start with, but then nothing. There aren't any leaks from the MC on the floor outside or inside the car, and the reservoir is full to the top. I did spread the pistons a very small amount before reinstalling, and it moved easily and shot fluid out of the disconnected hard line.

Could it take that many cycles to purge air from the lines? My helpers legs and patience aren't up to it!!

it takes a while to bleed the brakes on these cars... I don't know the exact reason, but they are not fun... persistance pays though

Fill the resevoir and keep it full. put a hose on the caliper bleeder put other end of hose in clear bottle or something that you can keep the end submerged in.

Get a stick to hold the brake pedal half way depressed. Open bleed screw TOP one and let gravity work for awhile.

get a beer drink half re-check resevoir and fill.

Now that you got fluid moving again. return the regular bleeding procedure. if you caliper got emptied it will take a bit to fill it. If your MC got drained cause you pumped all the fluid out doing the rears do this and then follow the above fix it method.

QUOTE (Joe Ricard @ Mar 28 2005, 07:24 PM)

Fill the resevoir and keep it full. put a hose on the caliper bleeder put other end of hose in clear bottle or something that you can keep the end submerged in. Get a stick to hold the brake pedal half way depressed. Open bleed screw TOP one and let gravity work for awhile. get a beer drink half re-check resevoir and fill. Now that you got fluid moving again. return the regular bleeding procedure. if you caliper got emptied it will take a bit to fill it. If your MC got drained cause you pumped all the fluid out doing the rears do this and then follow the above fix it method.

Okay, I'm game for anything at this point. I have it hooked up as you describe, and there seems to be a verrrry slow amount of fluid filling the clear tube hooked to the bleeder valve. I'll give it some time to see what happens.

Time to get a pressure bleeder me thinks

Wow it must have been brake weekend in 914land. 19mm master cyl thread and now this one... I rebuilt my front calipers this weekend and then spent a couple hours bleeding the brakes - now my pedal feels like crap and takes 2 pumps to stop the car. How many times am I going to have to bleed this thing?

I read over on the PP 911 BBS that to get good brake feel after installing new pads, you have to pump the pedal slightly to get the pistons to come out of the caliper just enough that you can shove the pads in with a mallet? They are saying the pads shouldn't just drop in with room to spare which is what happened in my case after I pushed the pistons ALL the way back into the calipers. Does this make sense?

Chris, keep bleeding. It can take 10-15 pumps or more to get fluid with an empty caliper, ask me how I know.

QUOTE (jkeyzer @ Mar 28 2005, 09:58 PM)

Wow it must have been brake weekend in 914land. 19mm master cyl thread and now this one... I rebuilt my front calipers this weekend and then spent a couple hours bleeding the brakes - now my pedal feels like crap and takes 2 pumps to stop the car. How many times am I going to have to bleed this thing? I read over on the PP 911 BBS that to get good brake feel after installing new pads, you have to pump the pedal slightly to get the pistons to come out of the caliper just enough that you can shove the pads in with a mallet? They are saying the pads shouldn't just drop in with room to spare which is what happened in my case after I pushed the pistons ALL the way back into the calipers. Does this make sense? Chris, keep bleeding. It can take 10-15 pumps or more to get fluid with an empty caliper, ask me how I know.

Jeff,

Thanks for the encouragement, you know what they say, misery loves company. I found your comment interesting regarding not fully retracting the pistons prior to inserting the new pads. I, of course, using my "every-other car works this way" skills, fully retracted the pistons to easily slip the new pads in place. I actually have the other side to do, so if I ever get the one side working, I'll try that trick on the other.

I did a little one-person tweaking last night, and verified that I am pushing air out through the caliper, so I don't think the MC is to blame, but damn that is a difficult job compared to my previous experiences with other cars.

QUOTE (jkeyzer @ Mar 29 2005, 12:58 AM)

Wow it must have been brake weekend in 914land. 19mm master cyl thread and now this one... I rebuilt my front calipers this weekend and then spent a couple hours bleeding the brakes - now my pedal feels like crap and takes 2 pumps to stop the car. How many times am I going to have to bleed this thing?

yep, this was national 914 brake week... I installed my new calipers from Eric this weekend... it was great!! I never realized how bad my brakes were! on one for the fronts, the inside piston was seized and one of the rears the adjuster didn't work for SHIT!

you have to bleed and bleed these bastrds... also bleed your prop. valve by opening the top line on it, under the car... air can get trapped there too

QUOTE (Joe Ricard @ Mar 28 2005, 07:24 PM)

Fill the resevoir and keep it full. put a hose on the caliper bleeder put other end of hose in clear bottle or something that you can keep the end submerged in. Get a stick to hold the brake pedal half way depressed. Open bleed screw TOP one and let gravity work for awhile. get a beer drink half re-check resevoir and fill. Now that you got fluid moving again. return the regular bleeding procedure. if you caliper got emptied it will take a bit to fill it. If your MC got drained cause you pumped all the fluid out doing the rears do this and then follow the above fix it method.

Joe,

I left the bleed valve open over night, and this morning I was able to pump fluid out immediately. Thanks for the tip, it seemed to really work.

Never thought bleeding brakes could be such a challange!!

Thanks again.

Couple of ideas for ya Chris.

Use a pressure or vacumn bleeder to push or suck fluid through the lines. I'm not fond of them for the final bleed but to get fluid in there they should help.

Otherwise lets go back to step 1.
You've verified the calipers work? Then check the lines, remove the line from the caliper & bump the pedal a tad, fluid should squirt out.

For 1 man operation i'd recommend is speedbleeders. Makes the whole job 10 minutes. Just open the bleed screw, hook up a line, pump the pedal, walk back to screw, check fluid, clsoe screw.

Vacuum pumps that pull fluid out of the bleeder valves don't bleed brakes well at all. They are great for testing vacuum components, but suck air from around the threads on the bleeder valve, and you'll never get a good complete bleed.
Here's what to do.

Get a spare cap for the brake fluid resevior.
Get a tire valve & stem.
Drill a hole in the center of the resevior cap, the same size as the hole in a wheel (or measure the narrow part of the tire valve).
Pull the valve stem through the hole.
Remove the plastic screen in the resevior.
Fill the brake resevior completely, not to the fill line, all the way full to the bottom of the tube that holds the plastic screen.
Put on your new modified pressure bleeder cap.
Drain your air tank to 10 psi, for cheaper compressors setting the regulator at 10 psi may not work. If you put too much pressure in the system, you'll blow off the blue lines that connect the supply lines to the resevior, or worse.
Take a clip on air chuck and clip it on your new pressure bleeder cap.
Bleed the brakes, starting at the furthest bleeder from the master cyl, and finish at the bleeder nearest the master cyl.
Pump the pedal hard about ten times and repeat the proceedure.
Do not get brake fluid on painted surfaces it will ruin them.
If the pressure bleeder cap retains pressure, bleed it down before taking it off the resevior.
This works very well, and makes it a one person job.
Replace brake fluid every two years.
Properly discard used brake fluid.

get 4 speed bleeders. put them in the top bleed holes.

k

Reading this brings back all those frustrations I had for months and months doing both the back and front brakes.....I have no better advice to post for my savior in the end was speed bleeders and a store bought power bleeder.

best regards

Thanks to all for the help. Any particular speed bleeder that is the "standard" for 914s? I would like to have them just to make the job simpler.

My wife was a great helper today and we have a working brake system again. Had the car out this evening and I still have a softer pedal than I would prefer, but functional. I have new OEM rubber brake lines coming from PP this week, so I'll wait to install them before fighting the rest of the air. The new rubber lines may make the difference by themselves as my lines are original 31 year old rubber - still look good from the outside, but I know that they get weird inside. I think I will invest in the Motive bleeder as well, since I like to change my own brake fluid and have 5 cars to keep running.

Anybody need 3 quarts of dirty brake fluid?

Thanks again....

QUOTE (ChrisFix @ Mar 29 2005, 08:02 PM)

my lines are original 31 year old rubber - still look good from the outside, but I know that they get weird inside

ummmmm, yaa

Those things can act like a one way check valve when they get bad. You are wasting your time trying to bleed the system with rotten old brake hoses. You'll never get good clean fluid out of the bleeders until you replace them.