General rear compensator

[antsuno2]

hi everyone! i seem to have underperfoming rear brakes again, when applied hard its hard to stop, so took it too the mot station and its showing little effort to the rear and he said its the compensator, but its not that old, ive had a poke and the piston is moving a tiny bit then presses on the arm and spring connected to the rear axle, my question is more fluid pumped to the rear calipers if the piston is in or out, ive tried adjusting it but cant work out whether i slacken or tighten the spring, has anyone had a similar experience or can help, or im going to bin it and fit an adjustable inline compensator, take to mot station and get him to set it, cheers Ant! http://cgi.ebay.co.uk/fiat-uno-brak...arts_Vehicles_CarParts_SM?hash=item334fe6748a http://cgi.ebay.co.uk/BRAKE-BIAS-PR...arts_Vehicles_CarParts_SM?hash=item5d26dea056

 

[the mk1 kid]

Hi Ant,

Last time i took my uno for an MOT i had the same issue - they cure?

Reversing at speed and slamming on the brakes was all that was needed as they're self adjusting - try it, it surprised me!!

Tom

 

[Louie Bee]

The reverse n and slam on at high speed adjusts the callipers / pads to disk (or shoes where drums fitted) and it's easy to over adjust and get them binding no prize for who did that :bang:

It’s not adjusting the compensator valve as it needs un bolting and manually adjusting.

This says you need to bleed the rear brakes after adjusting, and a 10KG weight for the turbo model.

https://www.fiatforum.com/gallery/showfull.php?photo=4225

It don't say but the lower the rear end is, the more effort that goes to the back so as you break heavily, the rear end rises and is becomes easier for the wheels to lock up, so braking effort is shifted away from the rear.

Sure you know Ant, but this is why the compensator valve needs readjusting after fitting lowering springs.. if not, too much effort to rear at all conditions and all so easily a slippy out end :dead:

 

[SteveNZ]

The spring on the compensator needs to be adjusted correctly. Basically the tighter the spring is, the more rear brake bias you will have.

I forget the specs but you need X kg on the spring at normal ride height. If you lower the car at the rear it will automatically increase the tension so it needs adjusting. I've got use to adjusting the spring for track use simply by feel, you should be able to do the same on the street.

 

[rawill]

The spring on the compensator needs to be adjusted correctly. Basically the tighter the spring is, the more rear brake bias you will have.

I forget the specs but you need X kg on the spring at normal ride height. If you lower the car at the rear it will automatically increase the tension so it needs adjusting. I've got use to adjusting the spring for track use simply by feel, you should be able to do the same on the street.

According to Haynes, put 55 kg in boot (5 door model) behind the rear seat. attach a 6kg weight to the bracket eye. Slacken the securing bolt and then retighten. (8.6.11)

 

[Louie Bee]

If you follow the link I posted, the Fait Porter Uno manual states 10KG for the Turbo