Rear Brake disc heating.

gazza12adv said:

That makes sense. Too much fluid might be pressurising the system and applying the brakes I suppose.
On one occasion when I pushed the front pistons on both calipers in to fit new brake pads fluid leaked out of the overflow pile at the rear of the engine. Made me wonder what was happening. Mine is a servo abs model though.

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He said the rear fluid level was low so the system wouldn’t be pressurising- the servo system is different to the later abs. The servo/abs has an overflow pipe for front and rear servo brake fluid reservoirs, that’s the fluid you saw when fitting new pads. You should have changed one caliper at a time, operating the brakes inbetween changing so as not to lose any fluid from the servo/abs modulator. The later abs is a sealed unit with no fluid reservoirs.

If the rear caliper is seized on its sliding pins or the pistons are sticking normally one pad will wear down a lot quicker than the other.

It’s an easy if slightly fiddly job to un-seize. Remove the pads. Clean the pin with emery and smear a bit of copper ease grease on it. If it’s notched where the pads have been seated replace it.

Look at the pads for any lumps bumps or corrosion where it touches the caliper. Clean and rub down with emery. Check the fit of the pin in the carrier holes on the pads. If it’s tight open up the holes slightly with a file.

Remove caliper from the swing arm and carefully pull the bracket away from the main body. You will now have two pins exposed one on the caliper one on the bracket. Clean both (I use WD40) and lightly rub down. Spray something like WD40 into the rubber boots the pins fit into and carefully clean out any old grease and brake dust. Make sure the boots seat properly in their groove and are not split.

With care pump the pistons out by a few mm. Make sure both move. If not hold the one that does move back with thumbs or a clamp. You just need a few mm more of the piston exposed than when the pads were in place, I clean the skirts of the piston and the caliper’s gubbins with an old toothbrush and WD40. Wipe down and clean again. Then dry with a nice clean cloth. Push the pistons back in as far as you can - check the m/c is not going to overflow. Do the non- sticky one first or you will probably push it out the caliper if you do do the stickier one first. Make sure both go right back in.

Smear the two pins with red rubber grease and reassemble the caliper and bracket. Make sure the rubber boots are properly engaged in the fittings. Remount it all, tighten to 25nm, install the pads the pin and the Rclip. Pump the brake pedal to reseat everything. It should be fine now until next service.

Once a caliper gets to needing this sort of treatment it needs it regular.

The fronts are different.

Steptoe said:

He said the rear fluid level was low so the system wouldn’t be pressurising- the servo system is different to the later abs. The servo/abs has an overflow pipe for front and rear servo brake fluid reservoirs, that’s the fluid you saw when fitting new pads. You should have changed one caliper at a time, operating the brakes inbetween changing so as not to lose any fluid from the servo/abs modulator. The later abs is a sealed unit with no fluid reservoirs.

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Yes I know Steptoe. I only did that the first time i changed the pads about 80.000 miles ago. Lol.
That's why I mentioned mine was a servo/ abs system.

AustinW said:

It should be fine now until next service.

Once a caliper gets to needing this sort of treatment it needs it regular.
.

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If you do all that you’ve said, and then do as I’ve said in my post (push caliper with foot etc etc) once a month you’ll will never ever get a seized caliper and will only need to lube the sliding caliper pins when you change the pads.

This is such a good bit of advice

Done exactly this. We'll, not sure I've actually changed the rest posts in 2.5-3yrs since I've had it . But I still do it periodically. I can push the caliper with my hands, no need for me foot


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