International Lancia Forums

I recently began reassembling the duplex servo on my Flavia 1800 Coupe. While making a comparison I noticed an odd arrangement on the second car that I have in the workshop. The inward vacuum hose is connected straight into the air valve and the filter that is usually fitted at this point has been removed. There is a tube in the bottom of the slave cylinder close to the main vacuum chamber and I assume this is where the vacuum hose should be. Can anyone advise?

Thanks and best wishes to all Lancisti for the new year.

Michael

You are correct. The hose from the vacuum valve either goes to its own dedicated filter, or, in the case of early cars, to the carburetor air cleaner. There is a separate manual concerning the Flavia & Flaminia brake system. It is a good idea to study it very closely because the system is insanely complex (and currently defeating my diagnostic efforts on a Flaminia I left off the road for a half year--too long).

Thanks Randy. I have seen copies of the brake manual and I will try and get a copy. I have not tested my brake setup yet but have recently had the servo and related cylinders rebuilt at some cost. Everything is loosely bolted onto the car and awaits my efforts to bleed the system. Does the system need to be pressure bled? My twin servo Alfa 1750 GTV will not be bled with pedal action alone and demands a trip to the brake shop every time the pedal goes soft. What are the symptoms of your Flaminia just in case I can apply this to my own situation?

Hi Michael. My problem is a classic Flaminia one and I've been meaning to post an inquiry on the Flaminia thread about it but that thread doesn't seem to get a lot of action. The brakes are staying applied. They are doing this so badly that they are sucking the vacuum out of the cylinder close to the vacuum tap resulting in a five cylinder engine! If I plug the vacuum line, the engine is happy but, of course, a rock hard brake pedal and mucho effort stopping the 3,300 pound car. When reconnected the one-way inline vacuum valve clatters frantically because it's just being asked to do too much. There's nothing wrong with the valve; I swapped it with the one on my perfectly-functioning convertible and the same thing happens.

The odd thing about this particular session of grief is that the brakes started doing this while I was actually driving the car. It was perfectly fine and then about six miles later, I was running on five cylinders and the now-weakened engine was required to pull dragging brakes.

The last time I had this problem, it was a ring of dried brake fluid preventing the master cylinder piston from returning all the way to its rest point. So I tried that first. I removed the cylinder and did find a little ring of dried fluid again though this time it didn't seem to interfere with the return of the piston. I cleaned everything up but no joy. My next idea was to re-grease the interior of the vacuum piston chamber because sometimes the big piston can stick. No joy. When I get back from my vacation I'll next pull the whole booster and disassemble and see what I find. I'm still suspicious of the vacuum circuit so I'll be checking the main diaphragm valve assembly.

In my experience, the brake system is the Flaminia's chief hair-puller. Dragging brakes result in broken stub axles in the transaxle (a well-known Flaminia weak point) and sidelined quite a few cars during the dark years when it was difficult to obtain rebuild bits. The system is VERY sensitive to air in the lines, for which reason I will first re-bleed (again!) my system before I conclude that I must pull out and disassemble the booster. While a lot of people blame the booster for a lot of the problems, I've had more trouble with the master cylinder and -- horrors! -- am running my other disc-braked Flaminia very happily with a Mitsubishi master down in place of the Lancia unit because I finally despaired of making the original work after MANY rebuilds and was sick of having a lovely car that I couldn't drive.

Bleeding is indeed supposed to be carried out with the system pressurized but this should not require a shop. It's been a while since I've seen a Flavia brake master. I believe it has one or even two plungers in the reservoir. You pull it (or them) up to pressurize the system and then bleed. It's actually very convenient. If their cups are in good shape, the plungers should stay up when you pull them (or it) up. If there is air in the line, of course, the plunger will drop down a certain amount to compress the air but if it goes all the way down, the cups are bad. Once the brakes have been bled and they work correctly, make sure the plungers are DOWN. You do not want a constantly pressurized system. Lancisti more accustomed to the drum brake systems, which DO require ambient pressure, often make this mistake.

When you do the servo, also disassemble the auxiliary membrane part. Under the pin there are two small pistons stacked on top of each other. One or both are often stuck.

I will do that Huib and thanks for the reminder. That membrane valve is my chief suspect now. The last time I took one of these apart I had to use compressed air to get those two pistons out. I hope one or both of those pistons are sticking because if I can't find the problem it will be off to someone professional. And I will have been defeated--yet again--by the Flaminia brakes! This particular car (single carb PF coupe) has worked pretty well for a long time and I liked having the full original designed system which IS more progressive and sensitive than the retro-fitted Mitsubishi arrangement.

Right. The Flaminia (and Flavia) braking system is an absolute masterpiece. No braking system is as sensitive and progressive and effective at the same time. It is well worth the effort (and money) to put it in order.