Brake Problems

[stanley1x]

I just replaced all four rotors and put new pads on my '74 1.8. The rear calipers were rebuilt as well as they were frozen. When I put it all back together, I could not get the air out of the lines after several attempts and now the brakes are worse then when I started. Only the front Left line truely is free of bubbles after bleeding. Where did I go wrong? Any help would be appreciated.

[Flieger]

Did you bleed in order of farthest from the master cylinder to the closest? Try tapping lightly with a rubber mallet on the calipers while the bubbles and fluid are coming out.

[quicksix]

Also try "burping" the proportioning valve in the bottom of the engine compartment. Start far way ,RR,then LR,RF,LF, like flieger said. Make sure you dont drain the resevoir while doing the bleed,good luck

[stanley1x]

Thanks I'll try both suggestions. I burped the master cylinder but it made no difference. Q: do proportioning valves go south or are they pretty strudy? Again, thanks for your suggestions.

[quicksix]

I think the proportioning valves are pretty stout as far as longevity.My six took a lot of fluid the first time after I rebuilt the brake system I replaced everything,and in the process I removed the pro. valve ang got a t from a vw system and put that in.Are you using 2 people or a power bleeder? The argument against removing the valve is that you loose the front /rear brake bias and it could cause the car to spin,I personally have had no problems.

[Joe Ricard]

speed bleeders
anything else is just un-civilized

[stanley1x]

I completely replaced the brake fluid using an Eazy bleeder pressure system filling each line in the recomended order. Once each line was refilled, my pal pumped the pedal and I worked the bleeding valves again in order. I got an awful lot of small bubbles -almost like a soda except for the left front line. I am considering rebuilding the MC (17mm). The proportioning valve is very difficult to reach. Can it be accessed from the top?

[quicksix]

You will have to access the prop. valve from underneath. It is a pain with everything in the way.The way mine acted is similar to what you described,lots of small bubbles,then suddenly it"caught" and I had a good pedal. Is your rear venting clearance set correctly?

[Dave at Pelican Parts]

Quick question: Are the bleeder valves toward the top of the caliper or toward the bottom? If you have both, use the upper ones for bleeding. You'll never get the air out if you use the lower ones.

This may be the only "is it plugged in" type of question I haven't actually run into face-first.

--DD

[Joe Ricard]

I have a 19mm MC for cheap if you want.

When the fluid turns to foam stop and drink beer. Sometimes takes a whole six pack before the foam settles back to fuid and big air bubbles. go slow Pressure bleeders are not what they are cracked up to be.

It could be possible the MC is sucking air but you would also see fluid on the pedal side of the bulk head under the carpet.

[dagger dog]

Did you adjust the rear calipers if they are standard "Porsche" (ATE) they do have adjustment on the rear ones small plastic cap on inside needs to be removed then there is a 13mm lock nut that needs to be loosend, then place a .004" feeler between the inside pad and rotor, turn the adjusting screw with 4mm allen clockwise untill you feel drag on the feeler, tighten lock nut, replace cap.

hope this helps
dagger dog