czardali

After the first freeze of the season I started up the car and drove it yet the front brakes were hesitating as if they were gripping the rotor. so i parked the ride and went in reverse and it accelerated slightly better. After another freeze and a day of snowfall I go to run the car and drive it around the block and its the back tires that are now acting sticky. I am ready to clean the brake parts and if necessary replace the pads however m question is it possible the calipers froze or seized? I guess I am trying to figure out what my worst case scenario is going into this cause she didnt have these issues before the freeze/snow episode.

'75

Do the symptoms continue or just the first couple brake applications? Could be a little rust on the rotors.

DUB

YES...it is possible that moisture got between the pad and the rotor and froze.

Changing out the pads might not do a darn thing ...except for the SAME THING again.
If it 'self corrects' itself after a few miles of driving...I would not worry about it. Because as you wrote...this was NOT a problem until you drove it in bad weather.

SO...when you drive it when you get home and can see snow/ice build up on or around the brake caliper....thus being right there by the pads....then you know why. And this can also be attributed to IF you have custom wheels that are really open and you can see the caliper easily. Also if you are driving in heavy snow....you can kinda expect this.

DUB

HeadsU.P.

Could also be ice behind the caliper piston seals. Dot 3 likes to take on moisture. When was the last complete brake fluid flush?

gg521

I suppose anything is possible. I lived in Michigan winters which get a lot worse than Texas and never had this happen - But !!

gkull

You have to bleed the brakes till clear fluid comes out of each bleeder. With the bleeder open you also need to lift up the calipers and squeeze the pads with a big C-clamp the force the old fluid out of the pistons. I've also seen people pry between the rotor and pads with a big screw driver to force the fluid out. Then all the water is out of the lines.

if water has been in the lines till they have interior rust you just have to replace them because the brakes won't release. Cars driving through lots of water splash go bad fast. I'm very Pro SS sleeved O-ringed stock calipers or aluminum aftermarket replacements.

I've been a C-1 - C3 mechanic for a long time!

theandies

Yes. Maybe there is a small amount of water in your calipers enough to freeze with the cold weather we've had over the past few weeks. It might be time for a full flush.
I switched over to DOT 5 years ago and have never looked back. I've had no problems with DOT 5. DOT 5 should be used if you don't drive your car that much to keep moisture out. Other benefits is it's wet boiling point (wet as in assuming the fluid has about 3% water by volume in it) is about 50 degrees higher than DOT3 and it won't eat paint if spilled. On the downsize it's harder to bleed the brakes because it has a tendency to absorb air more than DOT 3

DUB

Seriously?

The person wrote that the brakes were fine until it got cold and bad weather. Seriously doubt there is any rust in the system due to this current weather condition.

I know people do things in certain methods....and you are entitled to do it your way....and express your method....BUT...... I have never had to bleed a brake system by forcing/pushing the pads back. Thus pushing the pistons and seals into a potentially contaminated cylinder bore. You being a mechanic must know what I am referring to....and how back-asswards the 1965-1982 brake calipers are in comparison to most other brake caliper deigns.

Actually...in my opinion.,..pressing in on the brake pads that is something a person does not want to do...if at all possible ....and I can explain.

I can tell you that I have lost count on the number of Corvettes that when new pads were installed...the calipers leaked. When the old pads where put back in. On 50% of those cases...it still leaked. This is due not how the Corvette brake caliper is designed. REGARDLESS if it is lipped seal design or 'O' ring design. I have seen failures in both designs.

When a piston is pushed back into the cylinder bore...the cylinder bore behind the piston can become contaminated or worn due to the piston moving slightly due to incorrect run-out of the bearing and brake rotor. And this is due to the brake pad is wearing down...thus the piston is moving closer to the rotor. Thus leaving exposed cylinder bore in the caliper that the piston and seal will eventually go back into when new brake pads are installed and the piston is pushed back into the bore.

SO...if there is crap on the backside of the seal...and it is pressed back into this known dirty area. Because IF the brake fluid in the master cylinder looks like crap...then logic would tell us that the brake fluid in the caliper is the same way. Once the contact surface where the seal seals against the cylinder bore has not been effected...you CAN have problems. Not saying you always will...but if you can picture this...hopefully it makes sense that why do it if oyu do not need to.

And when bleeding brakes...it is not necessary to pressing the pads in to get out whatever contaminant is in the fluid. The fluid will come out taking whatever crap with it. If there is something in the caliper...it will come right out the bleeder if a person runs enough brake fluid though it....and NOT effect the pistons and seals.

With DOT 3 brake fluid...if water did get into it then brake system...which I highly doubt of any concernable degree...it would mix so easily with the DOT 3...that it then would become the milky looking blend I have seen when water and brake fluid mix.

And if the brake system had catastrophic failure due to frozen pistons and torn seals...enough to theoretically allow water in the system. The brake system would be leaking fluid like crazy.

I also have been working on Corvettes... as many know... for over 3 decades....for whatever that is worth.

DUB

HeadsU.P.

About Dot 5. When purchasing a new or rebuilt master cyl, the label on the box states;
Using Dot 5 will void warranty.
Must damage the piston seals in the MC? IDK

DUB

I have seen this also.

I think you might be correct...the type of rubber may have changed slightly and NOW the seals do not like DOT 5 coming in contact with it.

Why they have chosen to NOW stop allowing it...who really knows.

DUB

HeadsU.P.

Funny thing is, I do not recall a Dot 5 "Warning Label" on the caliper boxes, nor the proportioning box either. Just the MC box.
So maybe all those other "O" rings are ok for Dot 5. IDK

Dot 5 is soooooo much better.

czardali

definitely while in drive. i didnt give it to much of a go cause of the noise,.

czardali

What Im getting is that I should do a flush, clean my brake parts and report back.

HeadsU.P.

I can give you some tips on the flushing. Buy a brand new turkey baster that has not been contaminated with, well, poultry or soap & water. Open the Master cyl lid. Suck all that crap out of there into a old bottle and dispose. Now refill with new, clean fluid. There are four ways to flush the brake system:
1. Vaccum pump method.
2. Pressure (Motive) method.
3. Brake pedal method.
4. Let somebody else do it method.

theandies

I did the swap to DOT 5 soon after I bought my Vette in 1999. I did change all the calipers to SS o-ring design but I still have the original MC and have not had any problems since 1999 with DOT 5 and I'm still running that exact same fluid, in other words since 1999 I've not changed the fluid out and have had zero brake problems. Must not effect the MC seals at all.....at least not mine.

Griff2002

For what it's worth, I just replaced one of my calipers with an o-ring caliper and it did have a note that using Dot 5 fluid would void the warranty.

DUB

Using the 'turkey baster' to get the fluid out is a good idea. And when you get it all almost out. You can clean/wipe the inside of any major crud that may have collected on the bottom of the reservoirs.

Doing this will not cause any air to get into the system due to you can not get the fluid that is at the top of the ports inside the reservoirs...thus...no way for air to get down into the master cylinder...AS LONG AS the brake pedal is NOT pushed while doing this. I do it like that all the time.

That way your reservoir is clean and the fresh fluid you put in it will not immediately turn to crap when it blends with the crud that was on the bottom of your reservoirs.

And using the gravity bleed method is also 'do-able' by some peoples standards. May take awhile though doing it that way.

DUB

czardali

bros..update: so I checked my brakes and they looked damn good. I recently got my u joints and driveshaft ujoints replaced two months ago so I checked them too; still good. Took it over to Austin Corvette and now I gotta get my transmission rebuilt !