Flavia 2000 Brake Bleeding

[Brian Long]

Help!!!!' Is there a secret to bleeding the brakes on my 820-030 coupe?
I have bled many systems, B12 Aurelia , 819 Flavias etc, so my coupe has got me beaten at the moment.
I have fitted a new master cylinder and booster assembly. The gap between the actuating rod and the master cylinder is correct.
I bled the master cylinder on the bench with short tubes feeding back into the reservoir. I then fitted the master cylinder to the booster.
With an assistant, we bled the rear circuit and then the front circuit the 'usual' way ....pump the pedal, press on the pedal, release the bleed screw etc.
 We couldn't get a rock- hard pedal but it was holding at about half stroke. Went for a run and after two or three applications, the pedal began to sink to the floor although the brakes were still 'operating'.
Re bled the system again. No air in the rear circuit but got a rush of aerated fluid out of the LHS caliper and a few bubbles from the RHS one. Pedal was then back to previous position and feel.
Test drive and same thing. Firmish pedal for a few strokes and the it went to near the floor again.
No fluid loss...just a loss of sanity!
Any ideas?
Thanks in advance.
Brian Long

[Dilambdaman]

Hi Brian,

Buy a Gunson EEZIBLEED and when using it don't touch the brake peddle! You might have to modify the connection to the master cylinder.

https://www.youtube.com/watch?v=Lz8t6ZkVSQM

Robin.

[rogerelias]

Seems to point to a master cylinder problem to me

[chriswgawne]

Or it could be the remote servo - does it have its own bleed nipple? Air can be a devil to remove from the servo by simply pumping the brake pedal. Better to either use a Gunson Eezibleed or crack the connections on the servo till fluid runs out. Bit messy though.
On our Fulvia GTE with a remote servo there is also a bleed nipple on the 'rear brake fluid pressure valve' which sits under the floor  above the rear of the subframe. This valve is not shown on any of the Fulvia literature I have (or have I missed something?) and I didn't even know it was there until Martin Cliffe told me about 18 months ago.
Chris

[Brian Long]

Thanks  for very helpful comments. Following these and a few tweaks of my own I seem to have got rid of air in the system.
I had previously made an adaptor to fit into the filler neck of the fluid reservoir. It has a Shrader connector to which I connected an air compressor set at 10psi.
I clamped all three hoses and the pedal was rock solid. This suggested that there was no air in the master cylinder and hence it didn't need bleeding.
With all clamps still in place and starting at rear LHS, I took out the bleeder screw and the ball bearing. (Use a strong magnet on the side of a small screwdriver. The ball bearing will cling to the blade of the screwdriver). Then wrapped some Teflon tape on the bleeder screw thread and partially reinserted it. Connected a vacuum bleeder pump to it and pumped it to provide suction pressure. Opened the clamp and after an initial rush of air from the empty bleeder tube, fluid started to flow followed by bubbles of air. Clamped the hose, topped up the reservoir, emptied the vacuum bleeder and repeated the sequence a couple more times until there were no more bubbles. Reclamped the hose, took out the bleeder screw, reinserted the ball bearing and nipped up the bleeder.
The combination of positive pressure in the reservoir and suction at the bleeder apparently ensured a strong enough flow of fluid to sweep air out of the lines and caliper chambers.
Moved to RHS rear and did the same. After doing the rear brakes, the pedal was still firm.
Moved to front LHS and then RHS. Each time there was an expected rush of air from the empty bleeder hose followed by mix of fluid and air. After a couple of sequences on each caliper no more bubbles were observed. I made sure that the level never fell below MIN on the reservoir.
Road tested and the pedal was fairly firm but braking was vastly improved. Pedal moves to about 1/3 travel for good braking result. Softness may be due to rumoured flexing of the Dunlop callipers and a bit of 'give' in the hoses... or a pesky bubble still somewhere in the front system.
Thanks again for helpful comments. Hope my 'procedure' helps someone else along the way!
Happy Flavia motoring.
Brian Long.

[Brian Long]

Well, I guess I should have known better.
The NOS master cylinder had been stored 'dry' and the calipers, although they had been resleeved prior to you ownership, they had been resleeved in spheroidal cast iron.
After repeated attempts to get everything sorted, the calipers were stripped down and we found that the exterior part of the bores were rusted. This stopped the seals from progressing along the cylinder and caused excessive retraction of the pistons leading to excessive pedal travel.
Upon discovering this the calipers bores were resleeved with stainless steel and new seals fitted.
Still not ideal, so suspicion turned to the NOS master cylinder. On stripping it down, deterioration of the anodised bore was evident and the rubbers had score marks on them. Apparently the result of dry/prolonged storage. Hence, another stainless steel resleeving job plus new rubber kit.
Bled the master cylinder on the bench by recirculating fluid back into the reservoir via some banjo fittings and short pieces of plastic tubing. This was achieved by pushing the piston in amd out and pinching the tubes until no air bubbles were visible circulating.
Reinstalled the master cylinder on the booster allowing fluid to dribble out through the fittings as they were offered up thereby flushing the majority of the air out of any cavities etc.
I now have a vastly improved feel to the pedal although I suspect there might be traces of air lurking around the banjo fittings which are the highest point in the system. Next time I have the car on a hoist, I will do a final bleeding of the system using the conventional 'two-person' method. This will ensure a 'Rush' of fluid through each system to displace the last vestiges of air. I think, on reflection, that pressurising the system with a compressor doesn't move fluid quick enough because the fluid has to flow through the fine compensating port which restricts its flow?
Hopefully this is three days of the saga!

[Brian Long]

....oops, it should have read,  'the end of the saga".

[the.cern]

Well done Brian, that is quite a saga, but perseverance pays in the end!!! Having read that I am just hoping my brakes remain well behaved!!!!

                                                Andy