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Discussion Starter #1
I've been reviewing all the threads on brakes and bleeding and keep thinking I have my problem solved but it keeps throwing me curves. Here is my situation and I hope someone has some advice:

car: 1969 1750 Spider Veloce with ATE brakes (dual booster, floor mounted pedal)

When backing out of my driveway a week or so ago, when I pushed on the brake, it went straight to the floor and only could stop with the final inch or so of travel. The brake fluid reservoir was empty and the garage floor had very little drips on it (just the usual oil and some drops of different fluids). However, upon further examination after I lifted the car, the master cylinder boot had fluid dripping from it. Adding fluid and pumping the pedal would develop no pressure.

I examined the vacuum line to the intake manifold and it was dry with no brake fluid and so was the vacuum line to the other booster.

We replaced the master cylinder with a new one from Centerline. I refilled the reservoir and began to bleed the system using the usual two person method. Started with right rear, then right front, left rear, left front. Brake pedal still went to the floor; however, when pumping the pedal, pressure would develop and then after a very short period of time, it would again have no resistance.

Installed speed bleeders on all 4 calipers and this time, did right side first (both front & rear at same time). No change. Then, when starting the left side, noticed the front did not have any fluid coming out. Discovered that all the fluid in the front part of the reservoir was gone. Rear side still full.

Help! What to do next?
 

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I've been reviewing all the threads on brakes and bleeding and keep thinking I have my problem solved but it keeps throwing me curves. Here is my situation and I hope someone has some advice:

car: 1969 1750 Spider Veloce with ATE brakes (dual booster, floor mounted pedal)

When backing out of my driveway a week or so ago, when I pushed on the brake, it went straight to the floor and only could stop with the final inch or so of travel. The brake fluid reservoir was empty and the garage floor had very little drips on it (just the usual oil and some drops of different fluids). However, upon further examination after I lifted the car, the master cylinder boot had fluid dripping from it. Adding fluid and pumping the pedal would develop no pressure.

I examined the vacuum line to the intake manifold and it was dry with no brake fluid and so was the vacuum line to the other booster.

We replaced the master cylinder with a new one from Centerline. I refilled the reservoir and began to bleed the system using the usual two person method. Started with right rear, then right front, left rear, left front. Brake pedal still went to the floor; however, when pumping the pedal, pressure would develop and then after a very short period of time, it would again have no resistance.

Installed speed bleeders on all 4 calipers and this time, did right side first (both front & rear at same time). No change. Then, when starting the left side, noticed the front did not have any fluid coming out. Discovered that all the fluid in the front part of the reservoir was gone. Rear side still full.

Help! What to do next?
Years ago when I did the brakes on my 69 Spider (it had dual Bonaldi boosters) I started by just replacing the master. The parts guy told me I'd better do both boosters as well, otherwise the pressure from the new master would blow out the boosters (which it did about a week or two later). After rebuilding both boosters I found that one of the brake (pressure) switches was leaking (there were two on my system). I think I was able to get by only replacing one of them but definitely something to check along with the boosters. Brakes were rock solid after that.

Chuck
Colorado
 

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I too have a 69 spider. I have had brake problems with it for 20 years. It sounds like in your case, the feed into the front cylinder is not providing any fluid to the front cylinder. These new dual masters are re-pros, so it could be a defect. Another issue that plagued me for 15 years was a defective brake proportioning valve. this is not found on the earlier, single booster systems. the symptoms were a bit different, though. sometimes the brake would be fine, and other times it would go half way to the floor. If you are thinking of replacing this part, a simple screw-type proportioning valve will work just fine, or you could use a re-pro part.

good luck
 

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Discussion Starter #4
I'm guilty of not doing follow up. Sorry.

1) was able to get a proper bleed by following the service manual exactly rather what I read on the forums.
2) Exactly as 6alfas predicted, the front brake booster failed in few weeks. So, I replaced both boosters.
3) All is well. (yes, I also had replaced the 2 pressure switches. just happened to do it prior to all the other problems).
 

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Discussion Starter #6
I don't have it nearby but remember it very well.

1) since we did not have 3 people, I cheated and used speed breeders combined with those cheap vials for brake bleeding from harbor freight
One Man Brake Bleeder Kit
2) put one of each on each bleeder valve. Each mounted above the valve with some fluid in them.
3) opened both front and back right side speed bleeder
4) I stayed under car while my wonderful wife did the honors. Slowly press pedal down and allow it to return on its own.
While she did that, I scrambled between front and rear watching for air to stop and making sure vials did not overflow. Wife also watched reservoir level. When vials filled, stopped. Shut off breeders, emptied vials.
5) continued on right side until no bubbles.
6) repeated on left side.

We paid attention to pedal feel.

I have to admit we ended up doing it twice before we were satisfied.


After typing all that, my wife found the book we used. Brooklands Books. Alfa Romeo Guilia-Spider Owners Workshop Manual. 1962-1978. Last printing 2013. Page 112.
 

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Interesting that they recommend doing both calipers on one side at a time. I have always followed the process of starting with the caliper furthest away from the master cylinder then working forward so right rear, left rear, right front, left front.
 

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Interesting that they recommend doing both calipers on one side at a time. I have always followed the process of starting with the caliper furthest away from the master cylinder then working forward so right rear, left rear, right front, left front.
in the before times , before dual master cylinders and proportioning valves and emergency shuttle valves , you did the furthest cal first and worked your way around clearing the air from the sytem from the furthest to the closest . once dual cylinders and the various valvings showed up, it became necessary to not "unbalance " the system while bleeding and thus make the system lock out the " weak" side because it thinks one side has " failed " ... so that's why you do a front and rear simultaneously so the system doesn't activate a shuttle or a proportioning valve and keep one side from bleeding. the reason for all this dual system stuff is to allow the car to have brakes if one end leaks. if you bleed just one end , the car " interprets " that as one side " leaking " and tries to save you by shutting it off in one fashion or another and that's what cause most of the bleeding issues. best / simplest way to bleed these systems is with two glass bottles half full of fluid , two short lengths of clear plastic tubing that fits tight on the bleeders and submerges below fluid level in each bottle. now fill the reservoirs and open the bleeders... pump to the floor two or three times and refill the reservoirs making sure they never go dry. repeat until no bubbles in the tubing. then close bleeders and do the other side and you are done.
bleeding the master all by itself first goes a long way towards making life easy as well.
 
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