Hi all, i need to know if the brake system on a fiorino (uno van) is a single or double brake circuit system, as we have bled the rear brakes and the brake pedal feels perfect now, but we dont know if we need to bleed the front brakes too?
Technical single or double circuit brake system??
- Thread starter christopher watson
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Technical single or double circuit brake system??
SteveNZ said:
the cylinder were leaking fluid, so i had to fit new ones.
To clarify, it will be a dual circuit system, as this is a requirement in most countries for cars manufactured after a certain date in the 1970s...
On vehicles that are new to me, I always bleed all brakes at the same time. The reason you had to replace the rear cylinders was probably corrosion-related from water absorbed into the fluid (corrosion roughens the surface of the cylinder, wearing the seals). Therefore I would suspect that the front circuit would contain moisture too, though since the calipers are alloy there tends to be less of a problem. Brake fluid is cheap compared with the damage caused by not changing it (and of course the risk of brake failure...)
Just my thoughts,
-Alex
On vehicles that are new to me, I always bleed all brakes at the same time. The reason you had to replace the rear cylinders was probably corrosion-related from water absorbed into the fluid (corrosion roughens the surface of the cylinder, wearing the seals). Therefore I would suspect that the front circuit would contain moisture too, though since the calipers are alloy there tends to be less of a problem. Brake fluid is cheap compared with the damage caused by not changing it (and of course the risk of brake failure...)
Just my thoughts,
-Alex
Many thanks for the reply Alex, that has helped alot 
turbo_jim
New member
Not sure if its the same on a fiarino van, but on a cinquecento the brake circuits are diagonally split ie. front left with rear right and vice versa. I would guess that all fiats would have this same system
It's interesting to learn about the Cinquecento having a diagonal split. Some larger FIATs I have seen (and Lancia Thema etc.) have the diagonal split, but most smaller models have the front/rear split (front brakes one circuit, rear brakes the other circuit) in my experience.
Otherwise, the rear proportioning valve becomes complex (two circuits running through it) and in the case of an Uno, the rear brakes are so much weaker than the fronts that a diagonal split would give dangerously unbalanced braking if relying on one front brake and the opposite rear brake. Just my thoughts.
-Alex
Otherwise, the rear proportioning valve becomes complex (two circuits running through it) and in the case of an Uno, the rear brakes are so much weaker than the fronts that a diagonal split would give dangerously unbalanced braking if relying on one front brake and the opposite rear brake. Just my thoughts.
-Alex
turbo_jim
New member
I've just had a read through my collection of haynes manuals, and it would appear that Unos and Pandas do have the front/rear split, while cinqs have the diagonal system.
