454Big

Does anybody have a clue why the General (or Delco) has put springs behind the pistons of the brake calipers?

What bonus does this give the driver?

Can they be left out when the caliper is reassembled?


I had a discussion recently with Mark69, but we both did not have a logical clue - nevertheless, we came up at least with some ideas....

Forum members, what is your opinion or better: knowledge about this??? :confused: :confused: :confused:

Turbo-Jet

don't leave them out! they do not cause significant drag. these are fixed calipers, not floating, so the springs are required to keep the pistons square in the bore. if not there, the piston could get cocked and blow a seal. not good...




[Modified by Turbo-Jet, 4:34 AM 12/27/2001]

Eric 96

I would say that is reason enough to leave them in!!!!

mrvette

You are going on theory there, not fact, IN FACT with stock OR O ring pistons, leaving the springs out is a great idea, it makes for a slightly softer pedal, but with even DOT5 in the system, either piston works fine...
I still have the stock type pistons in the rear of my car, having changed over to the O ring style with the front caliper started weeping...plenty of pedal either way....locks them up if I want to....
NO pumping, no worries about a few mills of rotor runout, not that you'd want one TOO far out, but 8 mills is a hard requirement to meet....

I drove with stock pistons and no springs for 4+ years daily driving, and at super high speeds too....over 130 mph on several occations...never any troubles...not once....same with the O ring version....

I fail to see any downside to either spring removal or DOT 5 fluid....

GENE

yellow 72

I have o-ringed pistons, no springs, no problems :smash:

Geoff H

Hate to disagree with most posts here, but no way i would ever leave the springs out. I worked as a brake tech for a while and lots of probs caused by no springs or wrong springs, or worse mismatched springs eg different types in same caliper. This applies to all cars not just vettes and not just calipers.
they are there for a reason, to reduce pedal travel, so i say leave em!
Drum brake cars often have a residual line pressure valve, about 4 lbs, for this same reason so the brakes dont retract to far in between brake applications.
If the vehicle manufacturers, could save 5 bucks a car and leave them out the surely would have.

Hey just my opinion.................. :D

mrvette

Geoff, Hate to disagree with you but....

after driving for 40 some odd years in cars with all sorts of brakes, and disc brakes with all numbers of pistons, calipers, rotors, floating, fixed, biased....
4 wheel disc, disc drum....

I hate to say this, BUT, IMO....you are wrong....yes the pedal has more travel, but even with the notoriously 'spongy DOT5 silicone fluids, there is more than enough pedal to lock 'em....
and after 5 years of daily driving on both types of pistons....
well I believe MY experiences and eyes and observations of a simple system's operations....no mystery meat here,....really...

GENE

454Big

Well guys,

different people, different opinions!
I also thought of most of the things mentioned above, but wasn´t able to get a proof from anybody.
Your opinions helped me a lot - the experiences of course too!
Is there probably anybody who HAS or HAD PROBLEMS because of leaving the springs out?

yellow 72

The manufacture of my o-ringed pistons(Zero Tolerance) repeatedly stated in their literature to OMIT the springs :cheers:

Chuck Gongloff

If you're using the "O" ring kits, or the "Zero Tolerance" kits, the springs do no good at all, as after one rotation of the rotor (with runout) the pistons are pushed back into the bores and the pads do not ride on the rotor. The "O" rings hold the pistons back. The springs cannot overcome this resistance. Never tried no springs with "stock" pistons/calipers. Hope this helps. I have all 4 calipers built with "O" rings and NO springs. Works fine. Chuck

454Big

Chuck,
I also did this observation: the springs can´t overcome the force of the O-Rings that hold the pistons back!

mrvette

454, I thought to actually LOOK at the vette system some 5+ years ago when I had a cow putting the calipers back in place with springs installed, and didn't have the separator-installation tool...suffice to say, it's a mess without that tool...well I wanted the car back on the road, so I backed up and thought long and hard about it....they were/are the brakes for christsakes....

so anyway, the single piston floating calipers like most GM on rubber bushings, or the large Dodge system on just iron slots...the single piston system leads to the caliper going at an angle, piston cockedeyed in cylinder, and uneven pad wear....very common....I check/replace mine every 20k miles as a result of those experiences, not undifferant from many other guys on this forum....
even my '87 was a floating single piston, as I recall.....

well upon reflecting on what is going on in the operation the only thing I saw a problem with was the possibility of pedal travel...easily solved with a larger bore, which I was prepared to do if necessary, never did, it's not...

well anyway, all that happens is the pads are pushed aside like any other disc brake system, resulting in zero drag, and therefore act the same...

now let's not forget the disc brakes came from aircraft designs primarily...and up there I"m sure the requirements are a bit differant...so delco/bendix whoever....in 1963 or so when working on them for cars/vettes in particular...left them in, no troubles for doing so, and besides it was an engineering decision basedon the 'cover your axx' principal....and not open to discussion, on a time and material basis....
design was lock in, it would have taken an act of GOD to change it, it was institutiionalized by that point...so end of story....springs remained not for any fundamental engineering requirement of automobiles, just a hangover from other requirements......
I would LOVE for an actual GM/Bendix engineer who worked on this system to come here and tell the truth of what happened....but it's been 40 freaking years.....

GENE

ZD75blue

i read in another post, that the reason why we have to bleed the brakes when there is air in the system, is for the most part, the springs... The let the piston suck air into the system with rotor run out, great for a perfect car, but for all intents and purposes, better to just leave them out...

ZD

Chris B

From what I have read, the purpose of the spring is to reduce pedal travel for quicker brake response, based on the current racing brake technology ('50s, early '60s). There was no mention of a safety or functional neccesity for the springs.

An excerpt:
"They [pistons] are backed by springs that, when brake pressure is zero, take up clearance between the brake pad and disc"

The article: http://www.idavette.net/hib/BBfHInet12.htm

Chris

454Big

Any more suggestions or knowledge available???