66-69 4 piston brake caliper rebuild questions...

[Thrashingcows]

Finally got my reseal kits for my brake calipers on my Coronet. Got the calipers off the car and pulled apart and have been cleaning them and noticed that the pistons have some pitting and corrosion where the seals will sit and I feel that this will allow some seepage to happen past the seals.

Pics of pistons...Fresh out of the electrolysis rust removal bath....

And the caliper bores are in great shape since I had them sleeved in stainless 25 years ago!

So my question is to anyone who has resealed their calipers and had pistons in similar condition...did you do anything special to ensure a tight seal like add some RTV to the piston groove to help with the imperfections and pitting? Or did you just toss in new seals and assemble...did they weep or leak over time? Or are my pistons too far gone and I should talk to a machine shop about milling me up some new units?

 

[gkent]

What about a set of reman calipers ??

Alternatively, put your current stuff on the shelf and do a Disc-O-Tech conversion and say goodbye to any future problems.

 

[mrhemi]

You need new pistons (I know, un-obtanium). The pitting is very bad in the seal groove. Does the vendor that sleeved them for you previously have SS pistons available?

 

[R413]

Your pistons are junk, RTV, you are joking right?

 

[Tony Tee]

It might be too late! but, Rock Auto has new 4 Piston calipers for $89 I bought a pair in case I decided to go back to OEM style brakes. I just wish the rotors weren't so expensive.

 

[gkent]

RockAuto ... in Can $$ I'd be putting the current ones together and sending them as cores.

PLYMOUTH > 1969 > ROADRUNNER > 6.3L 383cid V8 > Brake & Wheel Hub > Caliper		Price	Core	Total
CARDONE 184473 {18-4473} Remanufactured Info FitsFront Left; Bendix Caliper; 4 Piston; with Metal Piston orFront Right; Bendix Caliper; 4 Piston; with Metal Piston		CAD$117.91	CAD$37.05	CAD$154.96

 

[R413]

They list as left and right the same, is that true? Other than the metal lines and brackets, the next is bleeder on one end and line goes in the other. So can the lines and bleeder be swapper end for end?

His are already stainless sleeved so not cores.

 

[Thrashingcows]

The company that rebuilt my calipers 25 years ago must have just bead blasted the pistons and tossed them back in, no way the pistons suffered that much corrosion sitting in heated/AC shop for the last 20 years.

Your pistons are junk, RTV, you are joking right?

Just tossing ideas out there that's all....;)

Guess I'll be trying to find a local machinist who can spin me up some new pistons, and may as well do them in stainless as well.

 

[Thrashingcows]

RockAuto ... in Can $$ I'd be putting the current ones together and sending them as cores.

PLYMOUTH > 1969 > ROADRUNNER > 6.3L 383cid V8 > Brake & Wheel Hub > Caliper		Price	Core	Total
CARDONE 184473 {18-4473} Remanufactured Info FitsFront Left; Bendix Caliper; 4 Piston; with Metal Piston orFront Right; Bendix Caliper; 4 Piston; with Metal Piston	View attachment 1345459 View attachment 1345460 View attachment 1345461	CAD$117.91	CAD$37.05	CAD$154.96

Might be cheaper to order those, pull the pistons out to use in my sleeved calipers and re-assemble.

I don't know why I didn't order these to start with....I never even clicked on them to see if there was any available, guess I assumed they would be no stock. I was so focused on finding reseal kits I guess.

They list as left and right is that true? Other than the metal lines and brackets, the next is bleeder on one end and line goes in the other. So can the lines and bleeder be swapper end for end?

His are already stainless sleeved so not cores.

I've looked at that as well and the bore and seat are the same on both sides of the caliper.

 

[1 Wild R/T]

The Cardone calipers are Chinese... Not reman, no core... I've installed a set and a single... They work if your Okay with Chinese calipers.. The same part work R or L by using the bleeder screw & the hose inlet in the opposing port..

As mentioned Pistons were available less than six months ago... I'd search for pistons...

I'm doing brakes right now on a car that has sat for over ten years... Had to rebuild calipers, wheel cylinders, replaced all three hoses, they were all plugged.. And I'm still dealing with the master cylinder.. Three bad ones in a row.. First one wouldn't bench bleed at all, no flow through the front port (rear brakes) Second one had no flow through the rear port & the third one works but bypasses, the pedal slowly sinks to the floor... Got two more coming ...

 

[Thrashingcows]

The Cardone calipers are Chinese... Not reman, no core... I've installed a set and a single... They work if your Okay with Chinese calipers.. The same part work R or L by using the bleeder screw & the hose inlet in the opposing port..

As mentioned Pistons were available less than six months ago... I'd search for pistons...

I'm doing brakes right now on a car that has sat for over ten years... Had to rebuild calipers, wheel cylinders, replaced all three hoses, they were all plugged.. And I'm still dealing with the master cylinder.. Three bad ones in a row.. First one wouldn't bench bleed at all, no flow through the front port (rear brakes) Second one had no flow through the rear port & the third one works but bypasses, the pedal slowly sinks to the floor... Got two more coming ...

I've ordered a set of the Cardone calipers....gonna just use the pistons and seals in my OEM sleeved units. I've been looking for pistons but can't seems to find any...do you have a source?

 

[1 Wild R/T]

I've ordered a set of the Cardone calipers....gonna just use the pistons and seals in my OEM sleeved units. I've been looking for pistons but can't seems to find any...do you have a source?

I'm not confident the Cardone pistons are gonna fit your OE calipers.... I'll look for pistons & post back shortly...

 

[gkent]

They do want cores for the Cardone's - that's why there's a core charge !!

I've bought Cardone's in the past - not these particular calipers - and they had "Made in USA" cast in them. But Chinese or not, they're better than what he has !!

 

[1 Wild R/T]

They do want cores for the Cardone's - that's why there's a core charge !!

I've bought Cardone's in the past - not these particular calipers - and they had "Made in USA" cast in them. But Chinese or not, they're better than what he has !!

Well, he's ordered them so I guess we'll see won't we... They use to be rebuilt originals but not anymore... Some places still charge the core cause it's pure profit if you decide not to sent a core... And if you do they loose nothing..

No luck on pistons, it appears they have dried up.. Sorry...

 

[R413]

I've ordered a set of the Cardone calipers....gonna just use the pistons and seals in my OEM sleeved units.

I wonder what the brake rebuild houses are using to rebuild these. Or are they doing what you are doing?

are the bores in the Cardone units even the same size as original Calipers?

you will Find out

 

[Tony Tee]

It might be too late! but, Rock Auto has new 4 Piston calipers for $89 I bought a pair in case I decided to go back to OEM style brakes. I just wish the rotors weren't so expensive.

They

It might be too late! but, Rock Auto has new 4 Piston calipers for $89 I bought a pair in case I decided to go back to OEM style brakes. I just wish the rotors weren't so expensive.

They charged me a $28 core per caliper. So I kept them. I can't buy the bendix caliper cores for that price.!

 

[Thrashingcows]

Was thinking about this last night while working and I think I'll just run these new caliper and in the mean time I'll hunt for a local machinist who can make me a set of new pistons to fit my OEM calipers. I had not thought about the pistons being a different size...Well I will measure them and see I guess, good info to have out there for others going through a similar scenario trying to restore their cars.

Thoughts on piston material to use? I was just thinking of the seals and with a heavier steel/stainless piston the lower portion of the seal would, at least in my mind, wear quicker then the upper portion. So would a set of pistons done in aluminum be better?

 

[Tony Tee]

I was going to machine pistons out of stainless steel to prevent future pitting..but bought new calipers instead. Here's a picture of the Pistons and the oem piston measures 1.999" O.D. and the new one measures 2.000" O.D. oem one is one thousand of a inch smaller probably due to ware.

 

[gkent]

There should not be any wear on a brake piston, they just don't move that much (distance-wise) I suspect the .001 is just allowable tolerance.

Do NOT make your pistons out of aluminum. The fact that the calipers are iron will cause electrolysis due to dissimilar metals and they will deteriorate. There could also be issues with different expansion rates so you may need a bit more clearance - but how much is not in my realm of expertise. If you want lighter pistons, consider phenolic - which was used in many single-piston calipers.

 

[1 Wild R/T]

. If you want lighter pistons, consider phenolic - which was used in many single-piston calipers.

Phenolic pistons sucked... Every damn one was seized in it's bore....