I recently changed the rear pads & discs on a 2016 Toyota Yaris & strugged to get the piston to seat back into the calliper so that I could refit it. It turned out that you have to turn the piston at the same time as trying to push it home.I've never had this issue before, but I'm only used to working on much older cars. Is this because of the design of the seals nowadays or some other reason? Thanks.
Brake calliper piston
- Thread starter jj4091
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This is the self adjusting mechanism found on many cars.....it basically has to keep the pad in close contact with the disc or you would have a long pedal and handbrake travel - completely normal.
Often larger vehicles are switching to a disc / drum combination where there are both pads for normal braking and shoes for the handbrake.
John
Often larger vehicles are switching to a disc / drum combination where there are both pads for normal braking and shoes for the handbrake.
John
Thanks John but I don't understand what prevents the piston going back fully without turning it, is there something built into the calliper as the only exterior device I could see attached to it was the brake cable parts
The piston screws on to adjusting mechanism for handbrake.
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you have to have a brake rewind tool
you have to apply pressure at the same time as turning the piston (this can be in a clockwise or anti clockwise rotation depending on the design) its not the same as the old days of just using a g clamp to push them back in,.
https://www.screwfix.com/p/hilka-pr..._jhpUDG4WdgllUP_gWRoCtU8QAvD_BwE&gclsrc=aw.ds
you have to apply pressure at the same time as turning the piston (this can be in a clockwise or anti clockwise rotation depending on the design) its not the same as the old days of just using a g clamp to push them back in,.
https://www.screwfix.com/p/hilka-pr..._jhpUDG4WdgllUP_gWRoCtU8QAvD_BwE&gclsrc=aw.ds
Imagine a 'ratchetting screw thread' where the mechanism can turn one way courtesy of the handbrake cable and its lever, therefore advancing the piston, but is prevented from unscrewing itself back again.....I'll see if I can find a diagram somewhere.
John
Thanks John, sxturbo & troutybrown I can see what happens now. Sxturbo yes I have found out since there is a tool for the job, I had to struggle to do it with a pair of long nose pliers & a clamp but it took ages
Here's a VW fella, I guess the principle is the same no matter what the caliper John?
Skip to around 0.30, 1.07 and 4.30 the guy needs a tripod!
Skip to around 0.30, 1.07 and 4.30 the guy needs a tripod!
Yep, that's the one - many thanks!
The only car I've ever come across with manually set rear calipers was the Mk1 Mazda MX5....maybe there are others.
John
The only car I've ever come across with manually set rear calipers was the Mk1 Mazda MX5....maybe there are others.
John
So presumably the piston just gradually unwinds itself as the pads wear?
yes each time you pul the handbrake it unwinds itself, the reason for this is so you get a consistent strong handbrake
Passat b5 and b6 have the same system at rear.
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This is the same type of rewind set I got a few years back and it works admirably.
My tip for foot/hand brake calipers is ensure the handbrake lever and its stop bracket are clear of rust and covered in grease. If left, rust builds up between the two and jams them together causing a lousy handbrake. I take the lever and stop off, wire bush, grease and refit.
My tip for foot/hand brake calipers is ensure the handbrake lever and its stop bracket are clear of rust and covered in grease. If left, rust builds up between the two and jams them together causing a lousy handbrake. I take the lever and stop off, wire bush, grease and refit.
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