TeamSwift

This is not a swift, but hope it's okay anyway in general? Same principle anyhow on brakes I guess.

So this is the story:

The 1989 model camper car Citroen C25D (non turbo) was stored outdoor for 2 years and rarely used.

Was supposed to use it this summer, but no luck as the brakes were a total disaster and I was not aware of it. It looks like I have to abandon it for the summer and concentrate on next summer instead

At the drive to the EU test, the brakes suddenly failed although working perfectly before.
They jammed, causing my rattle can paint to melt on the rim. Cooled it down, think the bearing survived etc but time will show anyhow.

So this was what I did, I got hold of an open end spanner kit not to damage the connectors

1.Removed caliper, secured by two bolts. Use of 13mm and 17mm spanner
2.Pressed in the pistons by great force using special home made tool, a nut, bolt and plate.
(did not vent, only pressed in slowly!)
3.Installed new pads and cleaned calipers, copper grease on sliding surfaces.
4.Breaks would not work, they did not retract and jammed slightly, causing heat again
5.Caliper venting treads rusted, so bought new 2 calipers (Cracked around treads)
6.Discovered brake hoses clogged, bought 4 new ones.
Made new flanges for new connectors and spliced them into existing 5mm pipes.
7.Installed calipers, vented, took off master cylinder in vice, vented
8.Repeated 7 several times, but master cylinder now refused to give any resistance.

Opened master cylinder, gaskets inside looks OK but they are extremely soft.

My question is how the master cylinder suddenly could fail. I cannot see any leakages when I press the pedal a zillion times, just no resistance. From the master sylinder I hear "squish squish" sound.

Just strange it collapsed so suddenly when it worked fine. One theory is that the new braking fluid suddenly dissolved the gaskets inside the master cylinder?

Is the fault likely to be the master cylinder?
Maybe a stupid question as this is the only item left to replace.

I just have a hard time understanding it would suddenly fail.

What are your experiences fiddling with the master cylinder suddenly failing?

Okay new master cylinder on order, old one probably 26 years old

Make sure you use the correct brake fluid stated for your Citroen. Should be DOT3 or DOT4.. DOT5 synthetic is not compatible with your car.

Cars sitting for long periods can have sudden brake part failure upon reuse, due to moisture/ corrosion that can cause seal failures during a brake cylinder/piston movement.

I should have posted this in the brakes section, have asked to move or delete it.

Was puzzled over the sudden failure. I am using DOT4+.

But I have a job to do now, to change brake fluid every 4th year on all my cars. I neglected it, and result is broken brakes. I also learned its a good idea to open rear brakes and clean every year. Also learned to take off calipers for cleaning, also to be done every year. Never bothered before, I brake soft so brakes lasted 10 years

Anyway, have q in the brake section!

Mystery revealed: I had given up the car, but a neighbor dropped by. He borrowed me a bleeding tool, you connect compressed air in one and and it makes a vacume on some 5 bar or so and sucks out the fluid very efficient.

After pumping and pumping and much research, I had installed the calipers UPSIDE DOWN. This creates 4 air bubbles impossible to bleed unless you bench bleed it...

Well, I had 50% chance of getting it right... but missed it.