Technical Help!!!

[KK1]

Hello, does anyone know where I can get a rear passenger side brake calliper for an abarth today or tomorrow?

Blasted calliper piston is stuck so I cant get the new pads in.

Thanks

 

[NumanR]

Just to make sure you are aware but the NS caliper has a left hand thread to wind back the piston not right hand thread like the OS

 

[Deckchair5]

Why do they have threads on them?

 

[KK1]

Just to make sure you are aware but the NS caliper has a left hand thread to wind back the piston not right hand thread like the OS

****! lucky, I almost got the sledge hammer out.
Thankyou for the advice.
Blasted Fiat.

 

[NumanR]

Please send cheque to

NumanR,
C/O The Fiat Home for the Permanently Bewildered Technician,
Bath Road
Slough.

PS Decky, the thread is there for the handbrake mechanism self adjustment, you have to wind the pistons in when replacing the pads.

 

[Deckchair5]

<the thread is there for the handbrake mechanism self adjustment, you have to wind the pistons in when replacing the pads.>
Right, thanks. I'm still a little confused though.
If the front caliper pistons are self adjusting then why aren't the rear?
Why different handed threads?
Don't some cars have threaded caliper pistons on the front?

Been puzzling me for ages so any information gratefully received

Sorry, just naturally curious. Pysch tried drugs but only made him worse

 

[NumanR]

The handbrake mechanism on vehicles with disc brakes on the rear, and actually use the service pads as a handbrake, need a self adjusting mechanism, to maintain the handbrake travel at a near constant level. Because the hydraulic brake caliper has no mechanical operation to push the pads out, when you add the handbrake mechanism it has to operate the rear of the pistons and so a self adjusting thread is used as an ajuster. To push the pistons in you need to deajust the mechanism and wind the pistons in. Different threads due to the different sides of the vehicle, it could be for identification, but on later fiats the NS piston is left hand thread.

 

[Deckchair5]

Great. Thanks for that
As I'm bound to need to do the job some time or another I would have thought opening the rear discs bleed nipple and dumping the brake fluid out would help in pushing the pistons back in and also prevent contaminated oil being pushed back up into the system.

I would have thought it's best to use a dedicated brake caliper retracting tool which rotates the piston whilst retracting. Whaddya think?

 

[bircia11]

i used a pair of tin snips open them fit in the grooves and wind away
might not be the best way to do it but it worked for me!

 

[T14086]

Universal tool is around a tenner that fits a 3/8" drive ratchet.Dedicated winding tools are about £16-40.

Mondeos are the same....took me over half hour before realised