I've cleaned up the rear calipers and ready to rebuild but am not able to get the pistons out. Do they need to come out ?? Manual instructs to put a rag in where ??? and air compressor to where ?? or something else.... How do I go about the rebuild ??? btw, should I paint the calipers before the rebuild or just put them in clean ??
Ken in wild and wonderful WV...
btw.... still selling parts from my 89 parts car.....

 

yes you should totally clean them up and repaint them. You can run some crocus cloth in the cylinder to clean it but don't paint it or do anthing extensive.

YES the pistons need to come out. The entire point of a caliper rebuild is to replace the piston seals.

The manual is telling you to put cloth inside to prevent damage and apply compressed air to the brake fluid inlet port. The compressed air will fire the cylinder out.
Another method if you don't have air ( i didn't when i rebuilt mine) is to use a grease gun to pump the caliper full of grease. It makes a mess but the hydraulics easily push the pistons out. If one comes out before the other push it back in and use something to hold it until the other comes out.

There is a variety of pliers you could use on the inside in a slide-hammer like action, but it is more difficult and possibly damaging.

If there is any pitting in the chrome plated pistons (where they are inside the caliper obviously) then replace them.

When assembling lube everything with brake fluid.

Either plate the calipers like someone did in a recent thread or prime and paint them with a high temperature paint, preferably ceramic caliper paint.

EDIT:typos, I really need to make sure my fingers are actually doing what my head is thinking

 

When I read the book to put in compressed air, I felt like the dummy I am sometimes.... They popped right out and fortunately all four were rust free and pretty clean considering how bad the seal were... Will cover the piston holes and after finishing my sand blasting (not into the piston holes) will paint with caliper paint.
Ken

 

I would recommend only using glass media and cleaning the living daylights out of the caliper afterwords. One grain of sharp media and the seals are toast. Remember that the action is going on between the smooth surface of the piston and the square cut o-ring. The condition of the cylinder isn't as important as the finish of the pistons.

The regular spray can of ceramic coating you can buy an an autostore worked well for me. Just some plain silver stuff. I wouldn't go by their can on how much it will paint though. Somehow they get away with saying one can will paint 6-8 calipers. Maybe these are little honda floating calipers, but I've never gotten more than 2 calipers out of one of these cans. Lots and lots of coats

 

Using only glass beads.... seems I should cover the cylinders while sandblasting or not ?? Obviously should cover them when painting. After painting, coat the cylinders with Girling brake fluid, then add the pistons and press the seals into place with fingers ??? As dirty and yucky my calipers were, the pistons are really nice and shiny... BTW, should I remove and air clean the brake line connecting the two halves of the caliper to insure there is no sand blast media ???
thanks,
ken

 

it's not a bad idea to leave the old seals in place until after the glass bead blasting. This will protect the sealing surfaces in the seal groove.

 

Don't bead blast for painting, sand blast gives a better surface for the paint to adhere to. Also use VHT caliper paint it will outlast most other brands. I used it on my front wishbones and calipers still as good as new. I used another brand on my rear calipers and it is flaking already.

If you are going to replace the pistons leave them in when you blast, or tape off the whole inside of the caliper, the pad covers this anyway.

 

I blasted my calipers in 2 pieces. Don't forget to plug all holes and when you are finished clean the caliper with air then use prep-wash with a soft brush. DO NOT use abrasive or you will kill the sand blasted surface.

 

I used the plain silver duplicolor and it has held up for 4 years. Like i said though, the finish is important. I cleaned some MGB calipers and they flaked off because the finish was too fine.

The duplicolor cans also have a decent spray tip as well.
Ear plugs worked well to plug the holes in the caliper and pipe cleaner works well to make sure there isn't anything leftover inside its channels

 

There is not all that much more work required to home plate than to paint and the original look and protection is retained.

 

If you want clean the channels after blasting blow them out with dry air and then use a pipe cleaner and alcohol until it seems like nothing is really happening and then do it a few more times (new pipe cleaners each time) just for the hell of it

 

Thanks to all.... I decided to leave the calipers alone after the sand blasting (with glass beads)... They look really good. Of course, I cleaned them well, blew them off, soaked in brake fluid, cleaned off with air gun, used dental proxy brushes for cleaning the brake fluid holes. I did not mark the pistons specific for each cylinder and I did not get that warm tingly feeling when I put them back in... Several were difficult but they did move. New seals and dust covers and will work on getting them installed today. So the end is near ??? Well maybe

 

Sorry if I misunderstood you...but the calipers will rust into oblivion if you don't treat them. You can't just blast them clean and put them back on the car.

Don't sweat the pistons, they don't wear with the cylinder, the wear item is the seals themselves. As long as the surface of the pistons is good, you will be fine.

 

How long do you suppose it will take for the calipers to die of rust... I'm 72, will I outlast them ?? Could I put some rust proof stuff on them in place ?? Or must I remove them again?

 

It might not be the prettiest solution but I don't see why you couldn't use some hi temp spray paint on the calipers, even though they're already installed, and simply wipe away excess overpsray from the brake rotor and surrounding areas.


The ".....rust into oblivion..." warning is a bit melodramatic . The bare iron will indeed rust....and we all like to prevent rust when we can... but it's not like the calipers are gonna crumble to dust and fall off the car!

Cheers
DD

 

I totally agree with Doug...