1973 Cuda Front Caliper Rebuild

[SBDave]

A previous owner sheered off the bleed screw below the hex and the bleed screw was completely rusted to the caliper.  I broke one easy out so ended up using lots of heat (lots and lots of heat) and a better designed easy out system to remove that bleeder screw.  I feel like I should rebuild the caliper now just to make sure the rubber seals inside it are ok.  I have ordered a seal kit.  I looked up directions on how to remove the piston in order to replace the seals.  I've never done this before so....

I used compressed air with a 2" thick piece of wood to get the piston out most of the way but can not seem to get it any further with my hands.  The piston moved somewhat slow while I applied air until the last half inch or so and it really popped free and wedged itself against the wood.  Can I use a thinner piece of wood and compressed air again to get the piston all the way out? 


thanks!
Dave

[426HEMI]

that should be fine to do.  or you could do what I have done is put a rag there instead. 
Wood might be better for you to use.  Inspect the piston really good check for pits in it and if it has those get a new one.     Use eye protection also   

[SBDave]

I used 3 layers of thick cardboard.  It popped right out.  The piston has some light corrosion where the seal sits, below that it looks great.  I will try cleaning it up more tomorrow.  I'm a little more worried about the walls of the caliper where the piston sits... I'm sure there is a technical term for those.  They seem to have some corrosion.  The seal has rust stuck to it where ever it was up against the caliper, but it looks brand new where it seals against the piston. 

The groove on the caliper for the dust shield has lots of rust in it.  I used a wire brush and tried cleaning it out some which helped ( I was careful).  And I cleaned the whole caliper with lots of brake cleaner.

Oh, and I always use protection.

Thanks,
Dave

[acudanut]

 They don't cost much for a rebuilt one. 

[Chryco Psycho]

 
for $18 you can get e rebuilt one

[SBDave]

Yeah, $26 from Kragen is the cheapest I've seen.  I've never rebuilt a brake caliper before, so I'm gonna give this a shot.  If I'm not happy with their performance after this I'll just replace both front calipers.  I plan on upgrading my brakes in the future and was trying to avoid spending extra money on them now.  Please don't lecture me on how important brakes are, if I don't feel comfortable with their performance I will fix them.

On a side note, does anyone know what material the pistons are made out of?  It's pretty sweet stuff.  Looks like some kind of light weight composite (w/metal flakes in it???).

thanks,
Dave

[Bullitt-]

the piston surface & groove in the caliper where the seal goes is what is most important, the walls do nothing but contain the fluid    I believe my pistons were stainless...very heavy, hard & shinny.

   When you replace the piston & dust boot you need to blow compressed air through the caliper to balloon the boot...almost need three hands. 

[422STROKER]

I rebuilt my rebuilt calipers , was pretty easy, the rebuild kit was a few bucks.

Tom

Yeah I used a smaller piece of wood with a rag and some compressed air, POPPED out!

[SBDave]

I just cleaned the groove in the caliper where the seal sits using a small soft wire wheel dremel attachment.  I cleaned the bore using WD-40 and scotch bright.  Seems to have worked pretty well.  My calipers look like crap compared to those Tom! 

How exactly do I use the air compressor trick for reassembly?  I know I need to put the seal in first, but I have read several different methods for getting the dust boot seated in the caliper.  One method was to have the bottom of the dust seal hanging off the bottom of the piston and getting it seated in the caliper before the piston is installed.  Then sliding the piston through the dust seal.  The other method I read about was getting the piston started and pushing the dust seal down in between the caliper and piston using a "blunt object". 

thanks,
Dave

[Bullitt-]

This is directly from the Service Manual...."Lubricant" described as Ucon LB1145Y24 or equivalent. I used Vaseline.

  Coat the new piston boot with lubricant leaving a generous amount of lubricant inside of boot. Install in caliper by working into outer groove using fingers only. (Boot will seem larger than diameter of groove, but will snap into place when properly positioned in the groove.) Using a forefinger, slide around the inside of the boot to be sure it is seated, or correctly installed.
  Plug high pressure inlet to caliper and bleeder screw hole, then coat piston with a generous amount of lubricant. With fingers spreading boot, work piston into boot and press down on piston. (The entrapped air below piston will force boot around piston and into its groove as piston is depressed.) Remove plug, then carefully push piston down the bore until bottomed.

Basically when I held the piston gently against the boot & trapped the compressed air the boot opened up & swallowed the piston.   
        Slikern Owl Poo.

[SBDave]

Finished the rebuild.  I found the method that worked the best was putting the dust seal on the piston and letting it hang off the bottom.  Then I just angled the piston/dust boot so the boot seated itself in the back of the caliper and then worked the front of the dust boot in as I straightened it out.  The hardest part was lining the piston up while I pushed it back in.  I ended up just pushing around in different spots and it slowly worked its way in.  It took more force than I was expecting to push it back in, but I guess that means there should be a good seal.

Thanks for everyone's advice!
Dave

[422STROKER]

I just bought some brush caliper paint from the parts store.  Was easy, but stinky.LOL

Tom

[Cudakiller70]

I know this thread is 6 years old, but wanted to thank bullitt for the tip;
Quote;
Basically when I held the piston gently against the boot & trapped the compressed air the boot opened up & swallowed the piston.   
        Slikern Owl Poo.

Just rebuilt my calipers, this method was ridiculously easy.

The trick for me was once it's blown up like a ballon, stop blowing air into the caliper. I held the air in there by the rubber tip on the nozzle, when the air pressure drops slightly it allows the piston to go in just like bullitt said almost sucked it in. Thanks for the tip bullitt!

[Bullitt-]

    

[SBDave]

haha, I was just scrolling down through and saw someone responded to this 6 years later!  too funny, glad the info has helped more people out
Dave