Disc Brakes and Handrbake

[JDMicra]

Hi all

I'v just got a K11 Super S that has been garaged for some time. Brakes are squeaking away as I drive, sounds as if the pads are scraping the discs very slightly. Also, handbrake needs adjusting as it comes up very high to hold the car.

Anyone tell me how I can fix these? I'm still a bit of a newbie, but I'm assuming these are DIY jobs
Thanks !

 

[Skinner_87]

Hi all

I'v just got a K11 Super S that has been garaged for some time. Brakes are squeaking away as I drive, sounds as if the pads are scraping the discs very slightly. Also, handbrake needs adjusting as it comes up very high to hold the car.

Anyone tell me how I can fix these? I'm still a bit of a newbie, but I'm assuming these are DIY jobs
Thanks !

If its been sat for a while mate its proably the pistons sticking the calipers from lack of use, this means the pads wont back off the disc under ratation as they normally would..

To free them i normally take the pads out & gently pump the brake pedal / push the piston back in & repeat a few times

It will scrape as well untill any surface rust is worn off the discs

 

[pollyp]

the rear disc calipers tend to suffer from:
* sticking/seized pistons - piston either just needs cleaning up or if its pitted, a new piston.
* pads sticking on their runners - just needs cleaning n regreasing.
* sticking/seized caliper guide pins - clean & regrease or if its very worn loose, replacement.
* sticking/seized handbrake cam mechanisms from dried grease and corrosion from leaking handbrake arm seal - needs an overhaul.

clean n regrease the pad runners and guide pins.

the discs are usually very rusty if not used for awhile.
drive for afew miles of braking to wear off the rust. check if the full face of both sides of the discs are smooth & unscored.

if the braking surfaces are still rusty n pitted n wavy I'd replace the disc. if the pads are still thick enough you could sand em flat on a glass plate for the new discs but its not guaranteed to be level with the back of the pads. normally I'd just replace em with new ones.

jack up the rear axle, in-gear and front wheels secured. fully release the handbrake and spin the rear wheels, they should be spinning freely. if not, then either the caliper pistons sticking, one or both of the caliper handbrake mechanism isn't return fully back or its seized = ineffective so the handbrake cable is set too tight in order to overcome the seized caliper mechanism and brake the wheel enough.

to access the caliper handbrake mechanism, inside the piston bore is a big c-clip deep inside which requires a special tool or a heavily modded clip pliers.

its a specialised procedure so if ur not confident of working on such critical parts of the car, either get a pro mechanic or brake specialist to overhaul/rebuild it for you or buy a replacement caliper.

for details on disassembling the mechanism i have pics on my blog page 2 post 94

http://micra.org.uk/threads/pollymobiles-rebuild.35251/page-2

is the car lowered? cos a misadjusted brake bias compensator valve can cause a restricted brake circuit and prevent some of the fluid from flowing back to the reservoir resulting in dragging rear brakes. written a guide bout it

http://micra.org.uk/threads/how-to-...-bias-compensator-valve-after-lowering.48457/

 

[JDMicra]

pollyp very helpful exactly the kind of post I needed! Going to try it myself and have a look at your blog THANKS .

P.S. no its not lowered, still the same as it left the factory, down to the original Nissan tape player XD

 

[JDMicra]

Okay so bit of an update . . .

pads still scraping slightly but seem to be backing off, jacked up back of the car and spun the wheels, you can just hear them scraping but no drag is felt. Garage reckons they will free off on their own within a few miles. Disc surfaces aren't perfectly flat, but nothing serious enough to cause concern so for now, they're going to see active service.

What I wanted to ask is about the handbrake. From where do I tighten the cable and how do I go about doing it? The handbrake holds just fine, but it comes up really high. I'd like it to hold with just a few clicks.

Any help appreciated, thanks

 

[pollyp]

just gotta try work loosen the mechanism.

I'd suggest:
1. loosen the 10mm handbrake cable nut under the handbrake till its at the tip of the cable
2. unclip the handbrake outer cable from its support braket hanging off the caliper
3. unhook the cable off the calipers swingarm
4. unbolt the guide pins n take out the rear caliper
5. now grab the handbrake mech swingarm with pliers or molegrip and work it back n forth all the way to loosen the cam mechanism. you should see the piston move in/out slightly, there should be no binding stickiness and it should spring back all the way.
6. to free up the piston seal, measure the position of the piston face, place a needlenose plier on the notches of the piston, push and screw the piston clockwise all the way in then unscrew outwards till it reaches the original position. don't unscrew it all the way out else it'll pop out the piston seal and you'll have to reinsert it. do it several times to loosen/unstick the piston seal.
7. set the piston near the original position. now the piston notches must be located at 12/3/6/9clock, if not then rotate the piston clockwise till the notch is aligned with the notch on the inner pad
8. hook the cable back on the swingarm and support bracket
9. bolt the caliper back on the guidepins
10. secure the outer cable clip on the bracket
11. pump the brake to move the piston out till it meets the pads, make sure the piston notch engages with the pads notch and the piston face is flush against the pads backing with no gaps. test the wheel spins without binding
12. tighten the cable end nut till its only slack when the handles fully down and just begins to resist the moment you lift the handle before the 1st click. the brakes should be fully engaged by the 7th click. release the handbrake and test spin the wheel again.

 

[r-reg-sr]

This is good. Should be a guide

 

[JDMicra]

Thanks again pollyp awesome will try and post how it turns out