Caliper Rebuild Problem

[Nut]

OK team..... what am I doin' wrong? Got my VBP rebuilt kit today. Unfortunately since my SS sleeved calipers are over 15 years old they have the lip seals and that's what I had to replace them with. So....... caliper taken apart. Sleeves in great shape, no pits in the walls; pistons also clean. Everything ready, new lip seals on the pistons, dust boots mounted, springs in place. Hmmm..... no matter how hard I push, twist or tap I can NOT get the pistons to budge back into the sleeves. They simply will not go in.... period. I lubricated both the seals and the walls too with new fluid. I already gagged up one seal so I can't rebuild both front and I have to buy another seal. What am I doing wrong?

Thanks........... Nut

 

[vigman]

Try the following

See how much clearance you have between the piston ( W/O seal )

Does it fit?
Look like you can get the seal in?

Then put the seal back on...use a business card to walk the lip of the seal into the bore of the caliper....

Works for me...

Vig!

 

[Nut]

Mike.... It's the right seal, fit is good. I'll try the card trick tomorrow. Too beat tonight.

Thanks for the tip.

Later.......... Nut

 

[vigman]

Your welcome bro!

Good luck

Vig!

 

[Muddy]

Nut

Though I have never worked on the calipers on a corvette I have worked on many different type of calipers. One thing that could stop the seal from going into the bore of the caliper is if the groove in which the seal sits in is not clean or is corroded. This will make the outer diameters of the seal larger. I also use silicon oil to lubricate the seal and bore.

Just a thought

Muddy

 

[cntrhub]

Did you swap one piston for another? Meaning.., are you installing the same piston that came out of "that" caliper? Is this caliper's bleed tube open to let air escape...(if not bench rebuilding?). Try to see if, (without the seal) if you can spin the piston 360 degrees inside the caliper. Did you blow out the piston with air and....umm, the piston hit the floor......oops! Feel for nicks at the outside edge of the caliper.
Make sure the seal's groove in the piston is corrosion free. Just a little bump of crystiallized brake fluid can be just enough to stop you from sending that piston home. Clean (Mud's thread) all three angled surfaces. Take a good pointed scribe and clean the 90 degree grooves. You'd be surprised how much you can get out of the corners. Remember, this is a quad seal. It needs to be square in the groove!
I'd make sure the piston will revolve around the caliper's bore... without the seal. This way, you know for sure, Vig's card trick is all that's needed.

 

[Nut]

Must not be my week. Vig, your card trick worked on two of the pistons. Hours later I just plain gave up on the other two. Going to try again tonight. The first two went in like a snap. The others...... well the card would not tuck the seal lip in correctly all the way around, and since I already gagged up one of my lip seals I'm being REAL careful. (Good thing I bought an extra kit). Stay tuned.

............. Nut