General Brakes problem on UT

[M@nticore]

morning everybody, I have a problem with my brakes, they work normally when used etc no problems, but today I wanted to replace my front brake pads and could'nt get the piston pushed back, as hard as I tried nothing happend, the only way i could get them pressed back is by loosening the bleeding screw. so any ideas on wtf is wrong, i'm thinking th master cylinder, what do u guys thing.

ps: what is the thickness of new uno turbo brake pads?? inc the metal part.

 

[custard]

front or rear?

 

[Biz]

Was the cap off the brake reservoir?

You'd be surprised the amount of people that forget the fluid has to go some where! lol

 

[circolo]

The front should push in using two levers. (The ends of hammers with a wooden handle are good). That said, I bought a brake wind back tool years ago, and it makes life far easier to push the piston back. They're about £7 from screwfix, or somewhere similar, plus you can do both the front and rear brakes.

As stated above, it's advisable to remove the cap off the brake fluid reservoir when push the caliper piston back in.

 

[M@nticore]

i did remove the cap,didn't matter what amount of pressure I put on it just didn't want to go back, the lever I used started bending and still no luck, as i said I had to open the bleeder screw to release the brake fluid before I could get it back.

 

[antsuno2]

as long as it went in easily in the end it should be ok, bleed it up and press the brakes until the piston comes half way out and see if you can turn it with a pair of grips on the edge of the piston, sounds like maybe you worn the previous pads and discs out a lot and the piston may have cocked out a little, Ant!

 

[sludgeguts]

As something of an 'expert' on UNO brakes (see thread 'sticky brakes'){would insert appropriate smiley if this thing would let me}, I have always used an old 'G' clamp on all my cars. I cannot remember any car where it has been a doddle to push back the caliper by hand - even with the reservoir cap off.
In fact, rather than remove the reservoir cap I prefer to undo the nipple & drain all the fluid. I figure that an old banger needing new pads will also probably need new fluid. You are supposed to replace pads in sets i.e. both front or both rear, but I like to replace everything - especially if I've recently bought a 2nd hand motor - At least I know I can rely on the brakes to stop me, something which most take for granted when they buy a car, you ever know how it's been treated.
So, for me, buying a used car always involves an inspection of the brakes, hoses & replacing the fluid.
I use a one man bleed kit which attaches to the spare tyre, the air pushes all the fluid out so it can be replaced with fresh.

 

[ChasesDragons]

Hi,
This is probably too late, but if the pistons are seized, they would easily damage any rubber seals in the calliper when forced back in.

It is ALLWAYS good policy to press the brake after removal of the pads, so that a wee bit more of the piston is shown - inspect this and clear any dirt/grit rings with brake cleaner and perhaps wire wool or light emery. Then clean and push back. I know it is a bit anal, but 10 more minutes saves you a few more pounds and maybe your life - I learnt this the hard way on motorcycles.

I got rear disks on mine, not sure if all unos do. Obviously release HB to push pistons back!!

Regards

 

[alexGS]

Hi,
This is probably too late, but if the pistons are seized, they would easily damage any rubber seals in the calliper when forced back in.

It is ALLWAYS good policy to press the brake after removal of the pads, so that a wee bit more of the piston is shown - inspect this and clear any dirt/grit rings with brake cleaner and perhaps wire wool or light emery. Then clean and push back. I know it is a bit anal, but 10 more minutes saves you a few more pounds and maybe your life - I learnt this the hard way on motorcycles.

I got rear disks on mine, not sure if all unos do. Obviously release HB to push pistons back!!

Regards

Good advice from sludgeguts (what a name!) about bleeding out the dirtiest fluid rather than pushing it back into the system

Chasesdragons, Uno Turbo came with rear discs, other models have drums with a corrosion-prone lever to push out the shoes for the handbrake. Good thinking about checking the piston surface condition, but I just thought I'd note that you'd have to peel back the rubber dust boot (on the Uno front caliper piston) in order to see the piston surface. I think before I did this, I would give the area a clean with brake cleaner (outdoors) first, or warm soapy water and toothbrush etc. as the dust boot outside 'concertina' tends to fill with dirt that you don't really want to get inside. Of course, if the dust boot is torn... it's a good idea to replace it!

Another possibility for the difficult piston return is that the brake hose could have an internal restriction that lets fluid through under high pressure (from the master cylinder) but not from the low pressure prying-back of the caliper piston? My feeling is that brake hoses get damaged internally when the brake caliper hangs on them during disassembly - oops... now I always tie them up to the coil spring with a cable tie.

Cheers,
-Alex