Caliper handbrake issues

[Optimus prime]

Hi Guys,

I'm having troubles with the rear right caliper not working with the handbrake, I've tried the following:

- Doing the handbrake tension routine but slackening off the tension and pumping the brake several times over.
- I have replaced the hand brake cable
- I've also rewound the caliper then preformed the handbrake tension routine.

I've come to the conclusion that the handbrake mech in the caliper is seized or similar. The handbrake lever moves on the caliper so that is free... It has to be within the caliper! does anyone have any advice on how to potentially fix this?

Cheers in advance

[Ardent]

it can be a slow job.

But manually winding the piston back and forth can can help free things up.
But in essence you have nailed the issue, for whatever reason the self adjusting mech ceases to self adjust.
Moisture in the brake fluid? different metals? the sleeve nut ends up seizing on the threaded bolt.
Therefore the pad wear is not accounted for.

You want to arrive at a point where the pads have an interference fit with the disc. So no range of motion is lost in merely moving the pad to the disc. Let alone applying pressure.

[Optimus prime]

I'll give that ago along with pumping the brake and handbrake in between adjustments. Failing that would you know if there's anything that can be done internally... otherwise my only other option is to replace it... but I do like fixing things 🙂

[Mr X]

https://www.mr2roc.org/forum/index.php?topic=65851.msg775279#msg775279

[Carolyn]

Bear with me.  You might have done all of the following, but I'm going to not make assumptions and cover a few possibilities.

If the lever is moving, that's a sign that the caliper is not too bad.  Possibilities - piston is binding as it's pumped out.  You can check its movement with the pads out and a gentle application of the brake pedal.  It should move significantly, not just a little.  (If it is binding, see bottom paragraph.)

When you wind in, wind out at least 1/2 turn to engage the mechanism.  If the pads are a bit worn, wind out a bit more, just to be sure.  Make sure the nipple on the back of the pad is engaged in the piston.

Also pop the pads out, take a pic of how the spring clips go in, take them out and clean their slots with a square file until you can see bright metal.  clean the clips (they are stainless and will clean up, no matter how scruffy they look).  Put the clips and pads back in.

Clean the sliders and lubricate with Ceratec.

Once the caliper is back in place.

Disconnect the cable from the caliper, start the car and pump at least ten times (twenty won't hurt).  Then reconnect cable and adjust.

If the piston is binding, take the pads out and gently use the brake pedal to push the piston all the way out, clamp off brake line and take caliper off car.  Remove the rubber outer seal (you'll probably need a seal kit from Ebay) take out the piston-seal inside the bore and clean out the groove it sits in. (I use a dental pick to get rid of hard build-up) Clean up the piston, put it new seal, wind the piston in and add a new outer seal.

Failing all that, Mr X's guide will see you through.

[Optimus prime]

thank you! i'll give these suggestions a go later this evening. fingers crossed it's an easy one

[Optimus prime]

After some playing yesterday I have not been able to fix the problem keeping the calliper on the car. Next stop, remove and give the calliper a good once over. Thanks for your help on this guys, I really appreciate your input.

[Carolyn]

After some playing yesterday I have not been able to fix the problem keeping the calliper on the car. Next stop, remove and give the calliper a good once over. Thanks for your help on this guys, I really appreciate your input.

Nothing like getting them on the bench.

You might need to use the hydraulics to get the piston out if it's stuck to the point it won't wind out.  No need to put the caliper back on, just connect the banjo up and have someone work the pedal slowly.

[PhilzMR2]

Mine has just failed the MOT on both sides. Footbrake passes fine, handbrake useless. The garage told me that they have seen lots of problems with MR2 Roadster handbrakes.
One customer had new cables and new calipers and the car only just passed on the machine. Not a good design from Toyota it seems.

[Carolyn]

This type of handbrake-in-piston caliper was not just on Toyota.. Honda and Nissan all had them.

Handbrake cables on old cars can start to seize up, but 9 times out of 10, the problem is mechanics who don't know how to set them up.

The handbrake cables have to be completely slack before adjusting.  Then you start the engine and pump the pedal at least ten times, then adjust the cables.

If a piston is sticking, the foot brake can work but not the handbrake because the hydraulics exert much more pressure than the handbrake lever.  In which case, the calipers require servicing.

Take the car to someone who knows how to do the job.  I've got two pre-facelift cars, both with rock-solid handbrakes and original calipers.  Just serviced and and adjusted correctly.

[ilovejapcrap]

My new Suzuki swift sport still use this type of calipers / brake


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