Gaffa

They unwind themselves as the pads wear, but when winding them in to fit new pads make sure you wind them in far enough to give plenty of clearance, fit the pads then pump the brake pedal, if you only just wind them in far enough to squeeze the pads in you can cause the brakes to bind.

As not all of the pads come with the nipple and as noodle grinds his off, its a safe bet they aren't really needed.

Dembo

The nipple on the inner pads is to stop the piston from rotating which is how it adjusts the handbrake as the pads wear. Don't grind them off!

Gaffa

So how does it work if your pads don't have the nipples ? I've not had any probs with the handbrake and my pads did not have nipples to start with

BenRNBP

The mechanism on my Golf I understand, the piston rotates and unscrews to take up the slack for the handbrake. I couldn't get my head around the piston being held in place but it's obviously some kind of internal mech. I'm going to have to take one apart now to see how it works

RobAp1

Had a feeling it was something like that but i didn't want to take a stab in the dark guess and look like even more of a pillock! This could be the root of many peoples handbrake seizing issues. Pins ground off and the adjuster never moves!

Dembo

What nobody realises is that the threaded stud isn't fixed, but has a bearing at the bottom so it can rotate. As the piston can't rotate the hydraulic force makes the stud rotate instead, and so extend itself as the pads wear out. The handbrake pushes on that stud.

If you don't have the nipples then I guess the piston might rotate, or maybe there's enough friction to make the stud rotate as normal, or perhaps a bit of both. It probably still works, but it's not what it's designed to do and you're wearing out the back of the pad and the piston unnecessarily.

Gaffa

But as the stud rotates when under pressure from the foot brake the piston is clamped against the pad so is unlikely to rotate anyway ?


I'm not disagreeing with you Dembo and understand your reasoning, but i have serviced a number of brake calipers with handbrake mechanism that don't have pegs on the inner pad.

Dembo

Well maybe. But the cross on the top of the piston is there for a reason, and that reason is to line up with the nipple on the pad. Obviously somebody somewhere had good reasons for designing it this way.

BTW The GT86 has a separate drum handbrake inside the hub, so the caliper is just a caliper and you don't have any of this tulipe.

Gaffa

So has the Subaru Impreza, but they still have their faults and need regular servicing as they get moisture in the drum

Rich007

interesting topic and useful for me as I am about to change the rear pads and disks (with help).

My mechanic has said he needs a special tool to wind the pistons in so the pads can be fitted. is that right? can this be done without any specialist tools?