Bias spring question
Thread Starter
Le Mans Master
Joined: Jun 2005
Posts: 5,037
Likes: 520
From: Texas
Bias spring question
Now that I have installed the bias spring, I have a question. The bias spring I got has a higher spring rate than the stock spring. It took multiple times to install the spring due to the snap ring not seating properly and the spring popping out from tapping the piston against the palm of my hand.
What I am wondering about is 1) what sort of force is exerted on the snap ring and 2) what happens if the snap ring comes loose. Since I value 60mph - 0mph as I do 0mph - 60mph, I want to double check. I know a lot of people have done this and have no problems. I am not doubting the capability of snap ring (completely). I am more interesting in ways of testing whether my installation is fit for the road without putting myself or my car in harms way (oh yeah, and other people too
).
What I am wondering about is 1) what sort of force is exerted on the snap ring and 2) what happens if the snap ring comes loose. Since I value 60mph - 0mph as I do 0mph - 60mph, I want to double check. I know a lot of people have done this and have no problems. I am not doubting the capability of snap ring (completely). I am more interesting in ways of testing whether my installation is fit for the road without putting myself or my car in harms way (oh yeah, and other people too
).
Thread Starter
Le Mans Master
Joined: Jun 2005
Posts: 5,037
Likes: 520
From: Texas
Originally Posted by Pete K
I had the same thoughts. When I put a snap ring in, I usually take the tip of a pick, stick it in the hole and spin it in circles. If it does 4 or 5 revolutions and stays put, it is fine.
Originally Posted by MR NICE
I would try a few hard stops in a safe area.
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
I was nervous about it the first time I did it. I could not understand why they could not make the groove that the snap ring sits in deeper. Most snap rings "snap" solidly. Because of the shallow groove, that one does not. poor design.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
If the snap ring comes loose, the piston will be probably resting on the rod for the booster. Depending on the initial clearance, I would think the brake pedal would have a different feel at the top. And you may or may not leek fluid depending the clearances. I don’t think it would cause instantaneously catastrophic brake failure. If your loosing fluid, I think it would get soft first and air gets in. I would keep a close eye on the fluid level for a while. I’m not driving the car and it’s just my opinion. I understand your concern on that snap ring. 
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
After my difficulty with installation proved in part due to
a weak or 'sprung' snap ring, I posted recommending replacing
the snap ring. I feel strongly that the vendor(s) should include
a new snap ring with the spring.
That said, if the sharp edge of the snap ring is facing out of
the bore (rounded edge pointing to bottom of bore), if the
freeplay of the retainer in the groove is minimal (edge of retainer
does not come out of groove as retainer moves) and if the
spin test mentioned by Pete K is successful, then there is
a good level of assurance that the retainer will remain in
place.
BTW - the snap ring appears to be a standard size. I
bought my replacement at an industrial bearing supply house.
.
a weak or 'sprung' snap ring, I posted recommending replacing
the snap ring. I feel strongly that the vendor(s) should include
a new snap ring with the spring.
That said, if the sharp edge of the snap ring is facing out of
the bore (rounded edge pointing to bottom of bore), if the
freeplay of the retainer in the groove is minimal (edge of retainer
does not come out of groove as retainer moves) and if the
spin test mentioned by Pete K is successful, then there is
a good level of assurance that the retainer will remain in
place.
BTW - the snap ring appears to be a standard size. I
bought my replacement at an industrial bearing supply house.
.
Instructor
Joined: Feb 2000
Posts: 195
Likes: 0
From: Woodbridge VA
I'm getting ready to order one. From looking at the site (haven't read any install docs yet), it appears that you can install the spring with the master cylinder still in the car. Is this true? I asked because I did a search of some old posts and someone (I believe Corvette NC)mentioned that he created a jig to hold the cylinder while trying to get the spring into place. It seemed like a real PITA. Is it easy to install like the website claims.
TIA,
zzzasy
'96 LT4
TIA,
zzzasy
'96 LT4
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Safety Car
Joined: Jul 2003
Posts: 4,928
Likes: 1
Yeah, after trying for way too long. I reluctantly went down to shop and asked if one of the mechanics could do it. He was cool about it and brought it back about 10 minutes later saying, "That thing was a PITA!" I felt better about not being able to get it myself after he said that.
ZZZASY.... Good luck on that. It would have been impossible for mine to be replaced on the car.
ZZZASY.... Good luck on that. It would have been impossible for mine to be replaced on the car.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Actually I think the preload on the DRM spring is about the same as on the factory spring.
It's stiffer, but also shorter.
If that snap ring breaks, the spring will pop out into the back of the secondary cylinder, and you'll lose your rear brake pressure. And the pedal will feel wierd as the combo valve bottoms out.
It's stiffer, but also shorter.
If that snap ring breaks, the spring will pop out into the back of the secondary cylinder, and you'll lose your rear brake pressure. And the pedal will feel wierd as the combo valve bottoms out.