I just bought a '75vette that's been sitting for 15 yrs. I figure it'll behoove me to replace the calipers. Looking at vendors, I see stock 'lip seal' and O ring; I never seen a caliper that wasn't o ring (even my '72 Kawasaki). Which one's better? Also, any DOT 5 people out there?

 

I've always used the lip type and have never had a problem. The manufactures of the o-ring type claim there is less pedal travel (the last time I looked at them anyway) and some other benefits vs. the lip type.

 

you might a lot of opinions on this, so here is mine. O-Ring and dot5

 

As far as Dot 5, I have always heard that synthetic can give a soft pedal feeling. I personally use Castrol Dot 4 which has less affinity to water.

 

You said you havnt seen a caliper that was "not" O-ring-I think you have that backwards-O-ring is new.I have only installed 2 sets of O-ring calipers and so far no problems.A buddy of mine that used to sleeve calipers with SS for some of the companys says he doesnt trust the O-ring because of the design differance.The lip seal uses the pressure of the fluid behind it to seal tighter.I guess we will find out in years to come.

 

Zero Tolerance O-ringed stainless sleeved calipers using DOT 5 for 15+ years... not a minutes trouble

 

Have you ever looked inside? Is it just a groove with an O-ring in it? Is it a round groove or does it have some kind of fancy edges or a taper on 1 side? How many miles have you driven because they sorta imply these are best for cars that sit?

 

O-rings here also. But I know from history there are a lot on this forum that stand by lip seals.

 

If you cross-section an "o-ring", you will see a circle profile.

If you cross-section a "lip-seal", you will see, in general, a rectangular or square profile.

Caliper piston seals have historicaly been a rectangular/square cross-section, although most did not actually have a "lip" like the C2/C3 Vette piston seal... they were simply square cut.

In a common floating caliper design, the piston seal is first inserted into the bore where it is retained by a groove, and the piston is nudged into the seal. The piston has no retention groove for the seal.

The Vette non-floating C2/C3 design has the seal retention groove in the piston, none in the bore. The seal goes on the piston first, and then the piston/seal assembly is nudged into the bore.


Edit:

I've been doing brake work since about 1965. Typical piston seals are square cut, with no lip seal.
Commonly referred to as "o-rings".

 

lets get our facts straight...synthetic and silicone are NOT THE SAME product, the standard seal is an o-ring BUT it has LIP SEAL, the (fairly) new o-rings are just that an o-ring.......
...redvetracr

 

Oh yea -Its been so many years since I've worked on anything but a Corvette I forgot sometimes the seal is in the bore(outside).I worked for Cadillac back in the 70s.When I was asking about the groove I was talking about the groove in the piston.What does it look like ? Yellow 72-can we take yours apart? For the good of the forum !!!These "O-Ring" calipers-are the seals round o-rings or are they square o-rings?

 

I bought the O-ringed pistons from Zero-Tolerance years ago when I was having problems with newly rebuilt leaking calipers. They are true O-ring design with an O-ring design piston. They piston springs were removed also.
Yes my car sits more than moves, another reason I'm using them

 

I've looked at the o-ring calipers and wonder why they had to change from the lip seal. The pressure on the lip creates a good seal, in industry you don't see any hydraulic cylinders without a lip seal, where I work anyways. The "square" seals your talking about, we refer to as quad seals. They're not completely square, they do have a small lip on each side. I'll stick with the lip seals and silicone fluid to keep the moisture out.

 

I think I can field this one...

The C2/C3 caliper piston "lip-seals" work great when they are first installed, and continue to work great as long as you drive the car often and give them some exercise, and, as long as your rotors are at or below the runout/warp spec.

If the car sits for long periods, the weight of the pistons (which is not really that much) causes the lips to crush or "flat-spot" on the bottom. Then they leak.

If the rotors have excessive runout, the pads rubbing on the rotors will transmit the pulsations to the pistons which will "pump air" necessitating regular bleeding to cure a mushy pedal. On severely out of spec rotors, once around the block is enough.

The o-ring design are more resistant to both maladies.

Having owned & operated my own 7 bay machine/repair shop, I've done literally thousands of brake jobs. As a New York State inspector, I was required to check for leaky wheel cylinders and/or calipers in order to verify a cars roadworthiness. I found a lot of messed up brakes, and honed a lot of wheel cylinders... and replaced a lot of caliper "o-rings" as they are called.

I own a case 580L Series II Backhoe... and the cylinder seals on industrial equipment is different than standard automotive hardware. Besides providing the necessary pressure seal, they include single scrapers, double scrapers, etc.

Floating calipers with a grooved bore, and a non-grooved piston don't require or have a "lip". The tight clearance between the piston and the bore precludes it.

 

This assesment is absolutely correct. I have seen the same thing in my shop, and have therefore adopted the policy of o-ring sealed calipers ONLY. I will no longer waste my time installing lip seal remanufactured calipers just to have them fail in 2 years. I only wish we could buy all the NOS calipers we need, No stainless sleeves at all. Change the fluid every 3 or 4 years, and let's see, they would only last 30+ years.

 

Got me convienced!

 

I spent over a thousand dollars trying to get Zero Tolerance to work - they NEVER did and they never made it right. They put my car down for almost a year. I sent them my calipers TWICE and they couldn't get them to work. In the end it turned out that the piston drag was so low the pistons retracted when the brake pedal was released, so I never could get a hard pedal. They retracted with two different (one new) master cylinders.

I now run SSBC aluminum calipers with no problems. If they are the O-ring type, they are designed to work unlike the Zero Tolerance items.

I use DOT5 fluid. With the SSBC calipers my pedal is as hard as concrete.

 

I like SSBC products as well.... been buying from them since they started their business... very nice stuff. They have a polished stainless M/C cover.. no corrosion or pitting issues (bling factor). Stainless bleeders, stainless pad pins etc etc. I use their stainless pistons as well. A little too heavy though.

I have had them do my calipers and send them back to me.

Do the ZT calipers have springs behind the pistons as in the factory design?

 

A similar question; does the o-ring set up use standard pistions?

 

If he is still in business (somewhere in NC) Zero Tolerance (Mike) sells billet o-ring pistons, he doesn`t sell calipers, he (I believe) is the guy that came up with the o-ring Corvette piston although he does not hold the patent. He is (or was) also anti SS sleeved calipers as the calipers are not bored on center for sleeves which leaves a lip of cast iron at the bottom that will interfere with his pistons (I tried them, didn`t like them in a race application and had to dremel out the bottom of each bore). BUT to answer there isn`t enough room with a ZTI piston for a spring.
...redvetracr