[ophthos]

After replacing the rear end and bleeding all four brakes, I noticed that my front disk calipers look like crap. Whats the best way to restore them. They are KH style calipers. Can i dismantle them, bead blast them and run them thru my parts washer? Should I just wash them, scuff them up and paint them? I have black VHT caliper paint but you need to bake them to cure the paint. Are there rubber seals in there that need to be removed?

 

[Knapper]

Yep, clean em, bead blast and paint. You can also get rebuild kits if the pistons and rubber parts are in tough shape.

 

[Knapper]

Also...if they are rusty, I soak them overnight in Evaporust before blasting.

 

[Mike the old grump]

Asuming they are rusty, evaporust works well. Don't have to worry about getting all the blast media out of em. I used to use nastier stuff, now it's evaporust for me.

 

[67gta289]

If you haven't procured the Evaporust yet, or the next time you need to get more, consider the Rust911 alternative. I made the switch and am very happy. Costs less ($3.75 per gallon instead of $20 or higher) and works just as well. It is concentrated, so you need to add water. As a result it takes up less space.

 

[ophthos]

Asuming they are rusty, evaporust works well. Don't have to worry about getting all the blast media out of em. I used to use nastier stuff, now it's evaporust for me.

If you haven't procured the Evaporust yet, or the next time you need to get more, consider the Rust911 alternative. I made the switch and am very happy. Costs less ($3.75 per gallon instead of $20 or higher) and works just as well. It is concentrated, so you need to add water. As a result it takes up less space.

So you just disassemble, soak it, dry it off, and paint it?

 

[22GT]

Yes, I have typically painted them with Cast Iron Gray. It's been more than a decade since mine were painted, and they are still holding up.

 

[Mike the old grump]

If you haven't procured the Evaporust yet, or the next time you need to get more, consider the Rust911 alternative. I made the switch and am very happy. Costs less ($3.75 per gallon instead of $20 or higher) and works just as well. It is concentrated, so you need to add water. As a result it takes up less space.

Good point. I've not tried Rust911. I'll look for it next time I need something.

 

[vegasloki]

So you just disassemble, soak it, dry it off, and paint it?

Yep. Use caliper or hi temp engine paint to survive the heat. If you blast them put something down in the bores like a clean shop rag and tape it up so you don’t blast the bores. You can get a small hand hone to refinish the bores as well.

 

[Vintage Ford Guy]

To pop the pistons out stick a bunch of rags between the piston and the caliper. Get a blow gun with a rubber tipped nozzle and stick it up against the brake hose opening. Goggles on! Fingers out of the way of the piston because its coming out like a cannon ball. One little blast of air and it come out with a loud pop.

If there is more than one piston you need to block the hole of the piston you popped out so the air can blow out the other piston. I use to just stick piston back the bore just a little and clamp it with a large "C" clamp and then blow out the second piston.

The indie bore of the caliper never wears but the parts of the caliper that slide on the spindles do (It depends on the type of caliper mounting system) Take a look at where it slides and make sure it is not worn and its clean of all rust and dirt. Lube the slide area with disc brake caliper slide grease. If it cannot slide it is going to wear-out the outer pads
Stick the seal with the into the caliper. Its different than most seals. The square lip of the seal is designed to twist just a little as the piston extends outward. The twisted seal then helps pull the piston back in so the pad does not continually drag against the rotor.

You can either lube the piston and cylinder with brake fluid or brake assembly fluid which is a gooey slippery stuff that works better for installing the pistons. It helps the pistons slip past the seal. The next part is easier if done using two people. Somebody has to stretch the rubber boot with both hands far enough that the other person can stick piston into the boot. Then you need to square up the piston with the bore. Stick one of your old brake pads over the piston and with a big "C" clamp slowly pull the piston past the seal and into the bore.

When you go to bleed the brakes you can just gravity bleed them starting with the passenger caliper. Open the bleeder. Remove the master cylinder cap and gravity will do the rest. Just make sure the master cylinder reservoir does not run dry or you might be bleeding the master cylinder too.

Once the brake fluid starts flowing into the steel line any air in the line will be pushed ahead of the fluid and into the caliper. By the time the caliper fills up there is no way any air can be left in the line. I will see guys get in the car and stomp hard on the brakes a bunch of times before bleediing them. That causes any big air bubbles in the line to breakup into tiny bubbles that are harder to get out. If you do bleed the brakes using the two man system, open th bleeder starting furthest from the master cylinder and have the other person as slowl as possible push the pedal down once and hold it there. Close the bleeder and let the pedal back up. Repeat until no more air is coming out.
Easy on tightening the bleeder, it does not need to be gorilla tight. I see a lot of them broken off.

I just prefer the gravity method. Once I see the fluid trickling out of the bleeder I shut the bleeder and I'm done. Nice hard brake pedal every-time.

Brake fluid will eat your paint right off of your restored calipers.

I had to go Motorcraft brake school for the F-600 Girling hydraulic brakes when they first came-out, back around 1984. The factory Ford instructor made a good suggestion. He said, air bubbles will cling to the inside walls of a caliper just like they do in a glass of soda. He suggested tapping the sides of the calipers to break the bubbles so can flow up and out of the bleeder. It really speeds up the process. The trucks have big calipers.

 

[67gta289]

Good point. I've not tried Rust911. I'll look for it next time I need something.

I’ve only found it on the internet, had delivered to my home. Need to plan ahead a few days.

 

[Mike the old grump]

I’ve only found it on the internet, had delivered to my home. Need to plan ahead a few days.

Thanks, I may check thehamb, garagejournal and VintageMachinery.org too. Someone once mentioned citric acid as an alternative, I've not tried it. It would be good to try a few different things and come up with something more cost effective. I have a couple old vise that would like to clean up one of these days.