Greasing Caliper Slider Pins - what's the best way?

[Guido]

Is there any easy way to grease slider pins? Mine are covered with a tight fitting thick rubber boot that I'm afraid of tearing if I pull it back too much to access the pin.

Also I'm afraid I'd never get a good seal again once I'm done.

What if I use some type of syringe to inject the grease inside there?

How do you do it?

[mainlymojo]

Hi

The boot/seal is there to stop muck entering the calliper pistons, they should come away but you still have to be carefull you don't damage them. I have worked on callipers on Vauxhalls (GM) and Fords which tend to fit lucas, and if you spray them with WD 40 you can open up the seal around the pistons and clean them out with WD 40 or a suitable brake cleaner readily available.

Then repeatedly push them back in with the flat shaft of a spanner or using a g clamp if you can get it on, then pump them out again with brake pedal until they get nice and smooth, its hard work and time consuming and your better off with someone sat in the car Then wipe them clean with a rag. Then you apply a small amount of copperslip inside them to assist them from seizing.

If they're badly seized and your skint and can't afford to replace them, you might be better off taking both sides off and carrying out a full overhaul on them. Also you could consider changing the fluid and bleeding it through the pipes till its clean. You will need a bleeding kit for this or you could attach a peice of clear rubber or poly pipe to the bleed nipple on the calliper and let the other end of the pipe hang down into a jam jar filled with about 2" of fluid to cover the pipe and to prevent any air being sucked back into the pipes when the pedal is released. This can be done after you reinstate the calipers.

You could purchase a service kit with new inner and outer seals, or if the seals are in good condition and the vehicle isn't too old and the pads haven't been changed before, you could just thoroughly clean the calliper unit without replacing any seals. Firstly start by removing the pads and the flexible hose and open the seals on the pins with a very small screwdriver and wedge tooth picks in and around it, to keep the seals open enough to allow fluid to enter and muck to come out. Put the callipers into a metal bucket/container and immerse them in a solvent or degreaseing compound. Petrol can be used but at your own risk but be careful for obvious reasons. Swish them about and leave them to soak long enough for the muck to run out. Drain them off and wipe them dry, then put them in a bench vice, reattach the flexible hose to the calliper then couple the other end to a foot pump or an air compressor (12v cig lighter type if you have one) via a small peice of 1/2" pipe and jubilee/hose clips or plenty of tape to make a temporary seal, or make an adaptor with suitable threads.

Then apply pressure to extend the pistons then push them back in repeatidly until you are satisfied they are smooth and free. Open up the seals again enough to apply a small amount of copper slip then replace the pads with new if old the ones are knacked and make sure the pads don't come into contact with the grease. Reinstate the calliper unit to the wheel hub and carryout bleeding procedure as above then tighten nipples when your satis fied the pads are close to the discs and slightly binding and brake pedal isn't spongy.

If you follow the link this will guide you more in depth with removing the pistons and changing the "o" rings and outer seals.


http://neptune.spacebears.com/cars/s.../calipers.html

Hope this helps

Martyn

[Guido]

Thanks Martyn for the detailed reply - it was very informative and I will keep it for reference when I need to rebuild the caliper. Right now I'm just looking for an easy/safe way to grease the slider pins that allow the caliper to move slightly when the brakes are applied. Every time I take my wheels off (twice a year) I'd like to lube these because they seized on my previous car.
I'm wondering if prying back the rubber will damage them and if the caliper has to be removed. This is for preventive maintenance, not as a repair.

The dealership charges $70 for this which makes me think they don't remove the calipers.

[mainlymojo]

If you price up some outer seal boots and purchase them if cheap enough, remove the pads spray the boots with WD 40 or some other cleaner, then pump the brakes till the pistons extend then remove the boots with a small tool or tooth pic, then clean and lube the pistons.

If your careful and your lucky you might not have to replace the boots with new ones, then at least you won't be caught with your pants down. Plus it will be an experience for you and a worry off your mind for the future.

By the way I forgot to mention when you push the pistons back remove the fluid rervoir cap and put a rag around it to absorb any fluid spilling over, this will aid venting the hydraulics, and you will have to top up when you have done.

You will probably find that the brakes will be spongy when you apply them after you have put them back together, this is due to the master cylinder being pushed back inside out with the fluid reversing action from the pistons being pushed back. But it will return to normal after you have pumped the brakes repeatidly for a few minutes.

Martyn

[MJ CORMIER]

Most of the boots fit like a tounge groove board, take an old tooth brush, clean around there real good you should see it, remove boot and lube away, I suggest copper never sieze, if the boot does not come off remove holder assembly and work from the oppisite side. Hope this helps.
MJ