Brake caliper windback tool and stiff caliper

[jon hill 3Participant @jonhill3]

Hi Guys

I decided to replace the disks and pads on my 15 year old astra.  After watch many youtube videos and consulting the haynes manual I am still at a loss as to weather the caliper needs to be rotated to push it back in?  I was working on the assumption that the caliper (not the guide pins) are able to free rotate and thus any pressure on them should push them back regardless?

I ask because I had some resistance with retracting mainly the rear single piston calipers, I did use a lot of wd40 and loosened the resovoir cap after extracting 100ml or so of brake fluid from the tank.  I didnt open the bleed valves as I didnt want to introduce any air or get brake dust into the fluid.

Any ideas?

[Craig BrownParticipant @craigbrown60096]

Some rear disk brake calipers require the piston to be rotated to get them retracted. I believe it is to do with the hand brake operation. If there has been no mention, in the Haynes or YouTube videos, about the need for a windback tool then I would think it doesn’t need one. I normally use a small clamp to help push the pistons back, very little pressure required just easier than pushing by hand

[Robert Atkinson 2Participant @robertatkinson2]

To confuse things it depends on shat brake system is fitted. It is not unusual for a particular model to have different brake components and even manufacturer depending on exact specification, fuel or even when / where it was built. I had a Fiat Croma which has the same running gear as a Vectra “C” and this had several different brake combinations. On mine the rear pistons had to be rotated but determining the direction was difficult.
Maybe better looking on a Astra forum. Probably got picures and videos.

[David JuppParticipant @davidjupp51506]

Wind back direction for the piston is typically reversed from side to side on the car – so ideally you need 2 variants of wind back tool, or fiddle about a lot on one side.  Often easier if you crack open the bleed nipple on the calliper too – this also avoids back-flushing seal wear debris into the ABS unit (which can lead to very big bills).

I can never remember which way to turn the pistons on my wife’s car – have to use trial and error each time.  At a push you can do it with a pair of long nosed pliers, but the wind bank tool does help.

If the handbrake cable connects to the callipers, the piston will need turning to wind the internal ratchet back down the threaded shaft.  If the car has separate brake drum/shoes for handbrake, then no need for winding back – just push.

[Author]

Posts