does anyone know the problem? when i brake my back brakes lock on and the front ones dont.
thanks

doesn't take alot of effort to make the back lock up on the drum set up as there's pretty much no weight on them

but you can check if the bias valves are in good condition that go to the rear, never heard of them going bad but if they do then too much preesure will go to the rear

As you look at the master cylinder there are 2 "blocks" either side of it with 2 pipes that go into and out of it, from the Master cylinder to the valve then to the rear

Ash

is the car on the 13 inch steelies? mine used to lock up easily until i put wide 14's on her

When were the fronts last serviced?

Cheers

D

This has started to happen to mine.
Mostly for the first couple of brakes then ok.
I have a service and engine mounts to do so will have a look at the valves then.

brak bias valves do go but no one seems to change them. mine and two of my friends have failed in the past so id swap them.... also service your front brakes...

im putting money on the bias valves... their not as strong as people think

its mainly the back left one (passanger side) just a question could it be that the brake shoes have come off in that drum as the handbrake isnt as affective anymore. Just a thought
Thanks

impossible... the wheel bearing would more than likely not rotate.... and if its the newer bearing its impossible for them to come off...

Sometimes if a brake is locking, the problem may actually be that the others are not working well enough...

Sorry for a bit of a thread highjack.
As i said i am sorting out my probs and the locking rears are one of them when i do the service and engine mounts.
But im having probs finding the front left mount (as you open the bonnet) 2 parts places say they cant get them.?
Thanks

fiat told me they cant get them anymore too. stongflex to a bush insert for the same price as what a new one used to be. there better... also your acutal mount doesnt perish just the rubber does so its a great replacement.

that the big cast one? there bloody expensive from fiat when they sold them. over £100 get a strong flex insert to fix it as clock said

Have had a similar thing recently, any decent braking force (but not too much) and it sounds like I'm doing an emergency stop except not stopping anywhere as quick as I would want to, and the car keeps on travelling too far before stopping.

Only once per trip though, so now I'm remembering to scrub my breaks off early on, then it's fine (for the rest of the day).

Mine used to be really strong the first time i used them on each journey

after that they were fine

It might be worth removing the drums and cleaning and greasing all the contact points. pushing the cylinders in to make sure there not sticking.

drum brakes are VERY effective brakes. lot better then discs. (only reson drums where ever replaced is because discs dont suffer over heating as quick... less rotating mass... lot cheaper to make.)
so if they rub even slightly or are not held back tightly by the springs, the leading shoe has a braking assist effect which lock the drum up solid.

They used to make twin leading shoe brakes, for even more self servo effect, but

Drums are not low maintenance they need fettling regular.

There is a separate rear brake pressure relief device for each rear wheel so when one goes you can do easy spin pirroooooetes in wet.

Noel

i had this issue with my back brakes. as far as i'm aware. cinquecento's do not have a brake bias valve as it's all controlled from the master brake cylinder. i found that my rear drums were slightly warped which caused them to lock. i did grind them with an angle grinder as a temp fix to make them more round. which worked but eventually changed for a newer set for MOT time.

mor1matt said:

i had this issue with my back brakes. as far as i'm aware. cinquecento's do not have a brake bias valve as it's all controlled from the master brake cylinder. i found that my rear drums were slightly warped which caused them to lock. i did grind them with an angle grinder as a temp fix to make them more round. which worked but eventually changed for a newer set for MOT time.

Click to expand...

The two pipes (?) out of the dual master cylinder should each go to a T piece connector, the T piece should/could be the pressure bias valve.

Noel