Trouble with brake bleeding, I can't get any pressure in the system |
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Trouble with brake bleeding, I can't get any pressure in the system |
Lozgib |
Oct 22 2016, 10:52 AM
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#1
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Newbie Group: Members Posts: 5 Joined: 29-July 16 From: U.K. Member No.: 20,236 Region Association: None |
Hi. I'm new to Porsche 914 ownership so please go easy on me. I have owned vw splitscreen buses for 30 years and restored loads of them though.
I bought a California 914 a few months back that is running fine now but had been sitting for a number of years needing the brakes restoring as all four callipers had sized and master cylinder leaked. I replaced all four callipers with rebuilt OG units from a reputable USA supplier together with a new master cylinder. I've bled the system 4 times using the easy self pressure method and combined traditional two person method and also combined both together as described on forums. I get clear brake fluid at each wheel with no bubbles but I have no pressure at all at the pedal. It goes straight to the floor. I've read every brake thread on this and other forums and can't find a solution. I have not replaced the pressure regulator as they aren't available her in the uk but would that cause zero pressure? I'm thinking there may be an issue with one or more of the callipers. I've got no leaks I can detect on the system. I'm stumped and lost for what to try next? Any help would be appreciated. |
Perry Kiehl Clone |
Oct 22 2016, 02:53 PM
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#2
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Unregistered |
Here's how I bleed a 914 brake system, from my post back in Mar 05.
Remember the "Search" function is your friend! Get a spare cap for the brake fluid reservoir. Get a tire valve & stem. Drill a hole in the center of the reservoir 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 reservoir. Fill the brake reservoir 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 reservoir, 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. Bleeding sequence (RR-LR-RF-LF) EDITED FROM ORIGINAL POST Pump the pedal hard about ten times and repeat the procedure. 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 reservoir. This works very well, and makes it a one person job. Replace brake fluid every two years. Properly discard used brake fluid. |
87m491 |
Oct 22 2016, 08:17 PM
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#3
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Member Group: Members Posts: 274 Joined: 29-July 12 From: Portland, the original! Member No.: 14,731 Region Association: North East States |
Not sure why anyone would go through this much trouble when you can get a $15 one person vacuum bleeder from Harbor freight! That said why spend $15 when you can try the method offered at the PMB site.
http://www.pmbperformance.com/gravity-bleed.html It works well. I just went through this on my new to me 74. Installed new M/C as well as 4 soft lines and then bled all 4 calipers. Having bled many cars and motorcycles before, I too was a bit dismayed that the pedal really never came back going caliper to caliper. (even after bleeding both top and bottom bleed screws) I went through a quart of fluid chasing out crap, be sure to keep the reservoir filled as the fluid can really get running! A few extra pumps after buttoning up the last one and voila, firm pedal. As others have said a short road trip might dislodge the last bubbles. I used the soft mallet and tap method. Keep at it any you will get it! Here's how I bleed a 914 brake system, from my post back in Mar 05. Remember the "Search" function is your friend! Get a spare cap for the brake fluid reservoir. Get a tire valve & stem. Drill a hole in the center of the reservoir 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 reservoir. Fill the brake reservoir 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 reservoir, 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. Bleeding sequence (RR-LR-RF-LF) EDITED FROM ORIGINAL POST Pump the pedal hard about ten times and repeat the procedure. 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 reservoir. This works very well, and makes it a one person job. Replace brake fluid every two years. Properly discard used brake fluid. |
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