Help diagnosing brake issue

[dannels]

Hi all

Had my first breakdown the other day - my Flaminia failed to proceed!

Both front brakes locked on. By the way if you ever have the ‘chance’ to breakdown in waddesdon - I think it could be the best place in the country to do so. We had tea and biscuits from the locals and multiple offers of the use of phones to call for help. Anyway I digress...

I got the Flaminia back home (eventually) with the help of a flatbed. By which time the brakes were working fine... any idea why the cause might be?? Can heat affect the master cylinder???

All advice welcomed!!!

Cheers
Dave

[lancianut666]

servo sticking on? don't Flavias suffer from this as well?
Clarkey

[Sebastien]

I had the same problem with my Aurelia B20. It took 2 years of trials and errors to find the cause. I also believed heat was responsible, as it happened mostly on very hot days. The front or the rear brakes would lock up, sometimes on the motorway, with no previous braking at all! Each time a 30 to 40 minutes cooling down period helped the brakes to release, and the car could be driven again.

Only the change to a new master cylinder in the end solved it: no problems since!

Explanation given was that the piston in the master cylinder did not fully retract anymore, maybe because of too great friction inside the bore. Thus the return line to the brake fluid reservoir was closed, and the trapped fluid could expand over time, and put on the brakes.

I was also told that Omicron could service a master cylinder, and put it in "as new" condition again.

Hope this helps!

[dannels]

Thanks - keep the views coming

I have a spare master cylinder - so may fit it in the hope it cures the issue

Heres a shot of my son using the boot as a handy sun shade whilst we await rescue...

[Dave Gee]

It sounds as if it is  probably the servo. This is a common problem. The best way to confirm this is to drive the car around the block until the brakes stick on again, and then release the servo vacuum pipe. Inside the servo is a small push rod that tends to corrode and stick over a period of time. It is possible to rebuild the servo. Several companies can do it but I have known servos to go backwards and forwards to the restorer several times before they are correct. Several people have changed the servo for a dual in line Spanish manufactured servo which works well both on Flaminias and Flavias. The only modification you would need to do is to put in a t-piece with a switch to operate the brake lights. They are normally available through a company called Car Building Solutions, but alas, at present they are out of stock. Hope this helps.
Dave

[Jay]

Sounds like the internals of the servo sticking. This was the first thing that went wrong with mine, although it was this happening to the rear brake circuit. I am sure this contributed to the half shaft sheering and the gearbox failing. What I did was to carry a small spanner and when it felt like it was tightening up ( it was very intermittent) I release the pressure and brake fluid from the circuit.

Omicron rebuilt mine as they had a jig with pressure gauges to test it and so far 6 years on its working fine. Better get yours fixed before Le Mans.

Also was the only other Bonnet Djet at Bicester reg no. BAE 703B 

[Jay]

Following on from Dave Gee comment regarding the brake light switch, I am thinking of converting mine to a switch on mechanicals rather than using a pressure switch. The reason being is that friends have said to me and this has back up by other flaminia drivers, that the brake lights only come on when you put a decent amount of pressure on. As the brakes are so good I tend to just dab and ride the brakes to slow down no real pressure and therefore the lights don’t come on. Also the GT has the most insufficient brake lights anyway.   

[dannels]

Thanks everyone!

Had a quick chat with Martin at Omicron - he thinks it could be either - so sent them both off to be tested on their rig.

Cheers
Dave

[Charles Frodsham]

Hi Dave

Hope you are well.

I have had servo problems in the past, but finally sorted after much work. My thoughts are that even if one rebuilds the servo, the problems will come back because of wear and corrosion on the pushrod as described above. This is particularly true because the cars spend many months over the winter not being used.

I now have a ‘standard’ servo with stainless internals, and it worked perfectly from the start. These are available on an exchange basis from out friend in NL.....Classic Lancia. Not cheap, and not always easy to communicate with....particularly after Brexit.....but I would highly recommend.

If it makes you feel any better Dave, I broke down on bank holiday Monday, due electrical issues. Firstly electrical supply to dizzy, secondly electrical supply to fuel pump. Flat bed job too!

On investigation, all the issues arised from the fuse box. The car had been fitted with modern plastic fuses. Apparently these have aluminium elements. The fuse box has copper terminals I believe. So catalytic corrosion is inevitable. This was so severe that it actually stopped the fuel pump completely!

I have sourced the correct 16amp ceramic fuses with copper elements, cleaned the terminals, and hey presto!

If anyone is interested here is the link

https://www.ebay.co.uk/itm/Ceramic-Copper-Brass-Car-Fuses-Continental-Torpedo-Type-Mercedes-VW-BMW-AUDI/332589247890?ssPageName=STRK%3AMEBIDX%3AIT&var=541693933852&_trksid=p2057872.m2749.l2649

It makes interesting reading!

So, this applies to any Lancias with copper terminals......Fulvia next!

Did  I hear Le Mans mentioned?

Cheers

Charles

[dannels]

Thanks Charles

Yes plan to be at Lemans Classic this year (if my brakes let me!) are you going?

Either way I know you have been before - any recommendations to a first timer?

Cheers
Dave

[lancialulu]

For what it is worth I rebuilt my Flavia remote servo with parts obtained from Omicron. My servo had the corroded rod issue but the rest of the internals were fine so new seals and diaphragms (the old ones were a bit stiff) and a new rod. Interestingly the Omicron part was zirconium coated so I hope it will not corrode so easily.

Just a trick if you are doing a rebuild and you have no reason to suspect the servo didn't work fine in the past, is to measure the push rod before dismantling wrt to the adjusting screw, and set the new rod to the same distance. Worked for me.

I have said before elsewhere I considered using the Spanish kit car dual channel remote servo but it does not fit a Kugle Fisher Flavia engine bay......

[Charles Frodsham]

Hi Dave
We did a package with Grandstand Motorsport, staying in the old town. Nice for beers and food between the racing. Included infield parking...pre 1966 only I think.....and a beer tent. I am sure camping is equally as much fun!
I am thinking about going.......would be good to get some Flaminias there!
Charles

[pchflyer]

I am unfortunately very familiar with this problem as it took me 3 servo rebuilds to correct the problem! The last rebuild was 2 months ago and now all is well. In my case it was 4 wheel brake freeze. Some tips I've gleaned: The servo has a history as the the source of the problem, but other components can also be involved, including the reservoir. Omicron offers a comprehensive rebuild and bench test of the servo, master, and reservoir, but it's not the most convenient for those of us across the pond. The Spanish replacement servo is currently out of production and unavailable. If just 2 wheels are frozen it *could* be something short of a bad servo. In my case, the diaphragm was the culprit (sticking) and was the only component that hadn't been replaced in the previous rebuilds because it's not included in a standard rebuild kit and looked ok.

[dannels]

Hi All

It looks like the 'critical' seal in the servo failed, letting brake fluid into the vacuum cylinder - thus not allowing the vacuum to release and locking the brakes on.

Servo rebuilt and refitted - all seems well with the brakes now......unfortunately.....its not the end...

In limping to a safe place to stop with the front brakes locked on, it seems I've put undue stress on the engine - now I have smoke from one bank - my money is on a blown head gasket...Grrrrr

One month to Lemans - the clock is ticking!

Dave

[Brian Long]

Another issue that can cause brakes to stay on is old, swollen brake hoses.
They will allow the bigh pressure from the booster through to the calipers but then lock the pressure therein when the brake pedal is released.
Brian