Rear Caliper Rebuild

[BYRNEY1984]

Evening all. Here is a quick how to, on rebuilding the rear calipers

First off. This is a couple of pictures of all the bits you need

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First up grease the handbrake lever bearing. I chose to leave this in as it is a special bearing

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Next tap or press fit the lever boot

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Once that is in and snug. Grease up the handbrake lever making sure to grease the recess

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Then making sure the recess is inline with the hole in the caliper bore centre( also make sure the bearing cut out is centred) gently press the lever in. It might require a gentle tap but you will feel when it is home. Then make sure the boot is sat in the lever groove

[BYRNEY1984]

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Next we have to fit the handbrake adjuster mechanism.
This is just a new oring on the shaft and grease the end so that the little pin sticks.

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This is then gently pressed into the hole in the caliper bore. Making sure the little pin stays on the end. The pin locates into the recess of the lever. So when the lever rotates it pushes the adjuster out. Thus applying the brakes.

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The next step is to place the adjuster locking washer in place. This locates the two ears into the recesses in the caliper. Its job is to stop the adjust rotating

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[BYRNEY1984]

Now we have to assemble the the spring return mechanism.
Here is the order everything goes in.
Little washer

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Spring

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Spring retaining cage

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Then this all needs to be centred to the bore and compressed. So that a circlip can be fitted holding the whole assembly down. You can either make a compression tool and struggle to get a pair of circlip pliers in there too. Or buy one of these

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[BYRNEY1984]

I find it easier with Toyota’s special tool. It is basically a nut with a thread that matches the coarse thread of the adjuster. You just screw it down and it holds everything compressed and centred allowing you install the circlip

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Next is to fit the piston seal in its recess
Lube it up and install it

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Then turn the piston upside down and put the boot on just the same as the front caliper rebuild

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I chose to just clean and reuse my pistons but you can buy them. But be aware when you buy them make sure they are loaded(fitted with all the female thread mechanism) otherwise you have to cut your piston in half, in order to remove the inners. Then fit it into the new piston and hold it it in place by a snap ring.

[BYRNEY1984]

Also if you see on the back of the piston it has a R stamped on the female thread part. This means the thread is righthand. Most calipers are righthand threads but you do get lefthand threads too.
So back to it.
Like the fronts start fitting the piston boot into the caliper. Starting with the rear

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Then wiggle it all in the groove and start to gently locate the piston into the seal

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Once the piston is in the seal and located against the threaded adjuster.
Gently and slowly wind the piston in. Take care not to catch the boot. If you feel it go tight back it off and check for anything getting caught

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Once it is wound all the way in wind it like this.
So that the piston cut outs are as in the below picture

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Then rotate the piston anticlockwise 90’ there is a notch/nobble on the caliper and the cut out will align with it.

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The reason we do this, is to set the handbrake

[BYRNEY1984]

Then install the dust boot retaining ring. I prefer to install the back portion first then just clip the ends in place. Gently pressing them with a plastic trim tool

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Thats all the hard stuff out the way.
Fit the slider boot by greasing it a little and sliding it into the caliper I find it easier to roll it in half length ways and push it in.

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Then the slider needs fitting into the boot. Noting that it has a groove at either end for the boot to sit in. Again new ones can be bought but mine were fine for reuse.

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Then tap or press the metal cap on the caliper

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[BYRNEY1984]

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Next is to flip it over and fit the carrier pin boot.
Again a plastic mallet is ideal. Just hold one half in place and tap the base into the calliper

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Then the next bit is to fit the handbrake cable bracket, lever handle and return spring. I haven’t done this part yet as I am waiting for them to be finished powder coated.
They are handed to each side. So don’t mix them up
Here are some spare ones.

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But that is pretty much it. Other than to clean it up and stick some decals on it.

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I hope this is of use and as clear as it can be. Thanks for taking the time to read it

[jimi]

Good write up
One thing you don't mention refitting the dust seal retaining clip ? or is that still to come ?
I would also suggest putting plenty lubricant in the groove for the piston seal. One of the things that causes brakes to bind on with MR2 calipers(front & rear) is corrosion in the seal groove, it builds up and compresses the seal onto the piston causing it stick and not retract properly.

[BYRNEY1984]

Ah you are right I missed that bit out. Will add it in. Not sure how I missed it but will blame it on the time of year and the beer haha

[BYRNEY1984]

Sorted I think. Even after proof reading it god knows how many times. But thanks for pointing that out Jimi

[jimi]

No worries, it's easy done I've done it more than once when adding articles to KY2

[BYRNEY1984]

Re-reading your own ramblings always makes sense, because you wrote it. It’s always the 3rd party that spots the obvious errors
But thanks.

[Wilkie Senior]

nice one there I can see what I missed rebuilding my last one, I was rushing I didnt get the threaded bar installed correctly the handbrake didnt work properly i just said the garage doing mot (my daughter in laws uncle) oh just get another CBA ha ha