Gazehound

I just rebuilt my brakes on my newly acquired 77 and a question that nags at me is, how are the o-ring type of seals better than the lip seals? I have rebuilt my share of automatic transmissions and they have lip seals on the pistons to engage the clutch packs. Hydraulic pressure builds up behind the lip seal and presses it against the bore for a tight seal. I can’t see how an o-ring can hold the pressure back without blowing past the seal. If some can explain this for me, I would be grateful. I am sure I am missing something simple in its design, but I am here to learn. Thanks.

redvetracr

It can`t and it doesn`t, it`s a band-aid that masks other problems like rotor runout.

noonie

Understanding that these oring conversions are not the ideal design, but the seal is still an oring seal.

Here's the cliff notes.

Brake system pressure is very low, approx 1800 psi max in panic stopping, of course trannies are also low.
Oring depending on clearance, compound, squash etc is easily over 8000psi and upwards to 10,000psi. Flexible lip seal not even close.
There is more sealing area for oring than lip seals
Orings sealing surfaces wear less due to application.

For the obvious

C3s were the only cars ever to have lips seals in brake calipers. Even GM wisely abandoned it.
Every manufacturer in the world from a Hyundai to Mercedes to $2500/wheel racing calipers use orings.

terrys6t8roadster

hey redvette, on my basically stock 69 every few months the brake pedal works its way down to the floor. I bleed them and off I go. no pulsing or leakage I can perceive. I was thinking of rebuilding the caliphers with the newer style pistons and kits fromVP&B [ did this on my 68 with great results, after upgrading the 68 to Wilwood these calipers are still in service on another 68], back to the 69, the rotors were the typical crudy look of a car that received only 2000 miles of road use in 8 years from the previous owner and I figured that just driving would clean them up, they look ok now, now the question, from what you said the problem is you think that slight rotor runout might be causing this problem? thanks Terry

fanmanbd

Over the past 35 years my vette would sit for an extended time for one reason or another. Each time it was resurrected the lip seal calipers would be leaking. I finally wised up and rebuilt them with o- rings and no more leaks. A great upgrade in my opinion.

resdoggie

I guess some have luck with lip seals and others don't. I installed ss caliper brakes back in 1990. My car sits in storage every winter. I finally noticed a leak in one of my rear brake calipers last year in the spring. Took it off and opened up the caliper. Yikes! The brake fluid was not fluid but rather a goo. Took all the calipers apart, cleaned thoroughly, used crocus cloth on the bores and reinstalled the same pistons, springs and lip seals. Haven't leaked since.

Marlin

I also rebuilt all 4 of my calipers with o-ring seals. Works great with no leaks and very firm pedal now.

7t9l82

i have always used orings on several corvettes and never an issue. as a mater of fact, has anyone ever had an oring caliper leak?

jb78L-82

I have wondered about the 0 ring seals versus the OEM lip seals for years for one simple reason: I replaced all 4 calipers back in 1985 with SS calipers (with OEM lip seals-no o ring calipers back then) from VBP when one of the OEM calipers was leaking. I bleed the brakes every 2-3 years and have had zero issues with the SS calipers now for 28 years! Zero issues on a car that sits 99.9% of the time and is driven about 500 miles per year!

I often read where C3 owners seem to have constant issues with their brakes and wonder that something has to be wrong with the stock system to have all these problems. Recommendations like going out to the garage and stepping on the brake pedal weekly or monthly to prevent seal leakage etc. The bottom line is that the stock C3 system should be relatively maintenance free if the calipers have SS bores, the brake fluid is changed frequently (every 2-3 years in my case), and there is no rotor runout.

The stock C3 system is a terrific brake system even today, especially on the street! There are very few cars on the road today that offer a better braking system with the the exception of some very expensive sedans and sports cars. With 12 inch vented front and rear rotors with 4 piston FIXED calipers at each wheel- the C3 system was WAY ahead of its time and still is a great system, despite what is often written on the forum.

CMEPASS

Well here is my two cents worth. I have a 81 and after getting the car I went through and replaced all the calipers due to leakage and corrosion. Two years later all four calipers were leaking and they had the lip seals.I did research and one vender said to keep the lip seals from leaking you should go out and pump your brakes 10 times once a week if the car sits. Well that tells me it is a bad design for Vettes that are not driven much so I installed 4 new calipers with o-ring seals 4 years ago.I haven't had a caliper leak since. I think they are by far better if your car sits 5-6 months out of the year.

CA-Legal-Vette

One other aspect to add to the discussion is ease of installation. If you fold over one of the lip seals on installation, it'll leak immediately. I've seen sleeves, much like a piston ring compressor, that helps prevent this problem but it is still a little more fiddly to install.

O-rings, on the other hand, are essentially fool proof. Any idiot can successfully install them. I know that from first hand experience.

v2racing

The lip seals work great for what they were originally designed for. Problem is, most of these cars sit more than they get driven. The lip seals more often than not leak when they sit for long periods. The other problem I don't like is the lips only seal in one direction, so they let in air and moisture. Glycol based fluid with moisture in it is very corrosive. Most people don't change break fluid often enough for this type of seal. The o-ring seals are better suited for cars that sit a lot.

CaseyJones

I rebuilt my brakes with over-the-counter Auto Zone SS calipers two years ago. I drive it a lot (sometimes over 1000 miles per week) but intermitently. Some weeks not at all. No issues.

MSGT-R

O-rings, or actually, square-cut seals?
Up until now, I've never delt with a Vette.

doorgunner

My GM mechanic friend told me that back in the '90s.....GM redesigned the caliper O-rings to have a tiny ridge on the o-ring. He discovered the advantage of this when he had to push a warranty-car into the work bay.

He said the car required much less effort to move than a similar earlier model car!

The explanation he was given was that the tiny o-ring ridge caused the caliper piston & pad to "back way" slightly from the rotor greatly decreasing the force needed for the car to be rolled.

It makes me wonder if the "other" advantage was a slight increase in fuel economy/available usable H.P. (every little bit adds up)?

(and...no....he wasn't drinking at the time...LOL)

v2racing

They are regular o-rings. Square seals are better yet as they will slightly pull the pistons away from the pads for less drag. I rebuilt my 80's brakes with o-rings and they didn't drag though.

I haven't seen a square o-ring conversion for the Vette brakes.

doorgunner

Hmmmmm...square seals must be a change from the "ridged" O-rings?

qwank

I use lip seals with SS sleeved calipers and no issues so far. I do keep extra seal kits in my tool box just in case though, because they are inexpensive.

0Todd TCE

Most later model vehicles run the square cut seal. The reason mentioned above is one reason - light drawback or release.

The other issue with a full 0-ring is they can "wind up" so to speak over time and twist. The can lead to damage to the ring itself (tear) or the possibility of it then creating enough force to create excessive pull back! Next pedal app and you find a very soft pedal as the piston is nowhere near the pad any longer!

The square cut seal distorts but will never wind up.

Solid LT1

Wow! this is NEWS to a guy like me who has disassembled many different brands of OEM brake calipers over my almost 40 year carrer doing auto mechanics/racing/restoration. ABSOLUTLEY DEAD FALSE BAD INFORMATION! Many OEMs use lip seals and there are also square seals to be found in both OEM and racing brake calipers.

Myself I use OEM Delco Morraine caliper seals and try to avoid some of the Chinese junk being sold on the market. "O" ring seals work great in racing calipers, but racing calipers are serviced between races or quite a bit more often that the brake systems used in daily driving