Hey guys.

I had by car jacked up in the air with both calipers showing the pistons. When I pressed brakes only the passengers side piston would come out. When I original took calipers off the both retracted fine it's just that it won't come out??

The passenger side brake disc looks worse then the drivers as it is all rusty and not shiney but drivers side looks shiny. as hence why I thought something was wrong.

Anyone have any ideas to issues?

Thanks any help welcome.

Sounds like the calliper has sized you may be able to free it with a bit of work but it sounds like it either needs rebuilding or a replacement

chris3234 said:

Sounds like the calliper has sized you may be able to free it with a bit of work but it sounds like it either needs rebuilding or a replacement

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Is it seized even if when it's to do with not coming out but goes in without a issue? Can it be ABS Pump? Sorry bit of a noob

It could be that you have a torn seal/boot that allows the piston to be pushed in but not holding pressure to push it out?
Any fluid loss?

Assuming all other things are fine (free caliper sliding, no punched pipe ...), there is also a possibility of a seized inner valve in the ABS unit, have a look at the hydraulic diagram … But you MUST feel an imbalance when braking, no ??
Also HOW are the pads worn ?

BRs, Bernie

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nikrox said:

It could be that you have a torn seal/boot that allows the piston to be pushed in but not holding pressure to push it out?
Any fluid loss?

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No no fluid loss that I could see reservoir was pretty much full when pushed pistons back in.

Bernievarian said:

There is also a possibility of a seized inner valve in the ABS unit, have a look at the hydraulic diagram … But you MUST feel an imbalance when braking, no ??

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

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Well the brake pedal is quite hard to press. To the point it feels like I have had new brake pads fitted but the pads are quite worn to almost legal limit

Re-install the "shiny" side and apply brake (be careful not to pop the other piston out), if the pedal comes that hard and the "rusty" side still Don't move, there is most probably an issue with the ABS controler. Disconnect the "rusty" side pipe and check for fluid coming out, that will tell a bit more.

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

Very little corrosion on you piston will upset your caliper. BigRed do rebuilt kits which will get you back as new performance. Take some time to clean the caliper properly, and fit new pads. You MUST do both sides.

HTH Simon

Bernievarian said:

Re-install the "shiny" side and apply brake (be careful not to pop the other piston out), if the pedal comes that hard and the "rusty" side still Don't move, there is most probably an issue with the ABS controler. Disconnect the "rusty" side pipe and check for fluid coming out, that will tell a bit more.

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

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Thanks Berne. 1) When you say the ABS module is that replacing the whole unit? Or is ABS pump and ABS module to separate parts. I also heard that if I changed the ABS pump/ module (waiting for my quick lesson from u there lol) I would need to get it programmed in?

2) on the 'rusty' side, when u say disconnect the brake line do u mean from where it attaches to the caliper or slight further up where it's more around the height of the coil spring?

That all depend WHERE the ABS unit is actually faulty: if it's @ valve level it can be replaced as is, but if it's the controler itself (MOS-FETs Inside) then you will probably need to get a "clean" one (tho I'm not 100% sure).

Check first if you get oil coming out the disconnected pipe (when braking), it can be open at caliper or a bit higher doesn't really matter, could even use the bleeder !

If Nothing or very small comes out, you have an ABS issue, if you get a decent amount of fluid getting off the pipe or bleeder, that 'd mean the built-in EV is not locked in closed position, nor driven in locked position …

The ABS block can be easily separated in it's two main parts, the rounded one with the pipe exits being the hydraulic section which contains the valves, buffers and the pump. They're connected to each other by electric contacts (nice); when dismantling have the electronic part on the top or you migth have some unwanted parts falling !

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

Bernievarian said:

That all depend WHERE the ABS unit is actually faulty: if it's @ valve level it can be replaced as is, but if it's the controler itself (MOS-FETs Inside) then you will probably need to get a "clean" one (tho I'm not 100% sure).

Check first if you get oil coming out the disconnected pipe (when braking), it can be open at caliper or a bit higher doesn't really matter, could even use the bleeder !

If Nothing or very small comes out, you have an ABS issue, if you get a decent amount of fluid getting off the pipe or bleeder, that 'd mean the built-in EV is not locked in closed position, nor driven in locked position …

The ABS block can be easily separated in it's two main parts, the rounded one with the pipe exits being the hydraulic section which contains the valves, buffers and the pump. They're connected to each other by electric contacts (nice); when dismantling have the electronic part on the top or you migth have some unwanted parts falling !

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

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Hey Berne. Currently out with the car and carrying out some tests wondering what u think.

1) I cracked the bleeder and pressed on brake and no fluid comes out of the bleeder. But it does no the other side.

2) Retracted the piston with bleeder open to see if fluid cones out of bleeder and doesn't.

3) I cracked the nut further up where the hard brake line meets the rubber brake line and fluid came trickling out at that joint

4) removed caliper from brake line entirely and when u turn on car (see video) and press abd hold the brake pedal the fluid dribbles out mildly quickly but still not sure if this is enough to sufficiently move piston. When u turn car off (and caliper is disconnected) it's still a hard pedal with a drip of brake fluid every 10 - 20 secs from the hose .
[ame]https://youtu.be/uxdO0fhiPhI[/ame]


So my issue us no better off I'm not sure if it's ABS, Caliper or blocked hose and don't want to through expensive parts if not necessary.

All help welcome

Hi, have you disconnected the brake pipe before the rubber flexi hose ? I’ve had flexi hoses collapse inside before

Maddogdom said:

Hi, have you disconnected the brake pipe before the rubber flexi hose ? I’ve had flexi hoses collapse inside before

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Did you get similar issue then ? Would make sense as the collapsed pipe could act as a one-way valve …

Next step in troubleshooting would be to disconnect the pipe at the ABS unit and blow air thru it to confirm it's not blocked. Air should also go thru the ABS unit from fluid intake (from master cylinder) to the caliper output.

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

Bernievarian said:

Did you get similar issue then ? Would make sense as the collapsed pipe could act as a one-way valve …

Next step in troubleshooting would be to disconnect the pipe at the ABS unit and blow air thru it to confirm it's not blocked. Air should also go thru the ABS unit from fluid intake (from master cylinder) to the caliper output.

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

Click to expand...

Never had it on a Punto, but I’ve had this issue before on other vehicles, and yes you’re correct it’s acts like a one way valve

The fluid will take the path of least resistance. If you have a slightly seized caliper on one side and not on the other, then the non seized caliper will appear o move freely while the other stays put.

You would need to put the working side back together and the pads in situ then try the brake pedal again, Although now you would need to put the calliper back together and try to bleed the brakes on that side.

you can put a lot of force on a piston to push it back but the master cylinder only pushes a small amount of fluid with each brake press. I think you have a seized caliper, but you've got a bit hung up on there being a blockage elsewhere and not fully investigated the caliper.

AndyRKett said:

You would need to put the working side back together and the pads in situ then try the brake pedal again,.

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why I told to re-install the "clean" side and inspect for motion on the (disassembled) "rusty" side …

BRs, Bernie

Just to let people know it turned out to be an ABS issue [emoji23]. But got a recondition one on and all is well

everson38 said:

Just to let people know it turned out to be an ABS issue ...

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... as I said in #5

BTW, thanks for posting the final result !!

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)