Brenden Rogers

I just have a few questions about the master cylinder and brakes in my 94 c4. Recently I had a problem occur when I was driving. My brakes seemed to have locked on. You could feel the car struggling to accelerate and when the brakes were engage, it sounded and felt like you were driving on nothing but rims. After coming to a complete stop, the car would not move in drive, but when in neutral, the car could be pushed easily. Now at the same time as the problem was occurring, a hole formed in my radiator which caused it to spray out hot steam everywhere. I have no clue how long steam was shooting out because I noticed it once I came to a complete stop and got out to examine the car. Could hot brake fluid cause this to happen? Or did I totally destroyed my master cylinder? Any feedback is appreciated. Thank you in advance.

billschroeder5842

This sounds less like brakes and more like a transmission issue. Have you checked your fluid? Check the level, color should be blood red and give it the "sniff" test to make sure it is not burn smelling.

Brenden Rogers

The fluid is blood red, it has the proper amount, and it dosn't smell burnt. I should note that when the car was in neutral and being towed, when I pressed on the brake, it still made a loud thumping noise and jerked the car around.

Patsgarage

Locked up brakes is normally more of a caliper issue than the MC. Jack up each corner individually and check if each wheel rotates freely.

Tom400CFI

And this is the clue:

If the brakes were "locked on", the car wouldn't move no matter what gear you had the transmission in. I would be scrutinizing the trans...that's for sure.

Brenden Rogers

Ok, but when I was in neutral and applied the brakes, it still jerked the car and made a thumping noise. Would the transmission cause that to happen too? I wouldn't think that's how it works.

billschroeder5842

What jerked? Where was the thumping?

The more detail the better.

81c3

Are your pads worn out down to metal? or maybe just one caliper has been locking up regularly and has worn the friction material down faster than the others...did you notice any pulling to one side or the other when braking recently?

Brenden Rogers

I don't really know how to best describe this but I'll try my best. The car jerked back and forth when I applied the brakes and made a loud repetitive thumping noise. It sounded as if it was comeing from the front tires, I couldn't tell which side.

Brenden Rogers

I can't really recall. The car just came out of the shop, it had the head gaskets replaced and the engine head rebuilt. I havent driven it for weeks. I also had the brake pads replaced about 2 months ago.

Tom400CFI

Didn't see those symptoms in the first post.

So...were you coasting down the road in neutral? And then you applied the brakes? Or you were stopped in neutral and you applied the brakes and it made "thumping"?

At first, it seemed like you needed help w/a specific problem...now your adding little tidbits...it's like hitting a moving target. Help us, help you. The full story will ALL the details really helps this work.

Brenden Rogers

Sorry about that, let me go through what happened but in more detail. I was driving home at about midnight and applied the brakes to turn into my neighborhood. When I applied the brakes to turn in that's when the car stated jerking back and forth and thumping as I stopped. I pulled over and got out to try to figure out what was going on. I initially thought I had a flat tire or more or less a completely shredded tire. After looking though, on the surface everything seems to be alright. That's when steam started coming out of the hood. At the time I shut off the engine and popped the hood. Now overheating is a problem I've been dealing with since I've had the car. The entire cooling system has been replaced. The car also just came back from the shop a day ago after have the head gaskets replaced and the engine head rebuild. After looking, I saw steam was shooting out of the radiator. Now this radiator has been recently patched do to the car rubbing a hole into it. The reason I got it patched instead of buying a new radiator was because this radiator was less than a month old and was a high dollar one. I decided to hope the patch would hold, which it didn't.
At this time I have my neighbor come out to help me get the car back to my house. I started the car back up and put it into drive. I let off the brake and the car goes nowhere. I gave it a little gas and you could feel the car struggling to get going, it almost felt as if there were weights on tires. After determining that I was going to get nowhere like this, we hooked a rope to the car, put it in neutral, and towed it down the street. The car rolled easily in neutral. At one point I had to tap the brakes due to the road being downhill. When I tap the brakes, it did the same thing as it did in drive. The car jerked back and forth and made the same thumping noise. This is the first time I've ever had braking problems.

81c3

Sounding more like a caliper locking up... or loose caliper bolts... The fact that you just got the car back from the shop and this is the first braking issue you've experienced, makes me wonder.... Did they have the wheels off for access while doing the heads? Was this a shop with Vette experience?

Tom400CFI

I'd be jacking it and inspecting the whee/rotor/calipers. I highly doubt that your Master cylinder is causing the issues that you're describing.

Brenden Rogers

I'm not sure if they took the wheels off. The head mechanic at the shop is part of the National Corvette Restorers Society. Weeks before though I took it to a different mechanic who is cheep and I'm pretty sure has no clue what he's doing to replace the brakes pads and tires. After looking at the wheels today you can see one caliper is missing a bolt. I'm guessing it just fell out while driving home. I

billschroeder5842

Yes, with more detail this is what my guess is as well.

Test you front brakes by putting your car up on jacks (both sides are better, but one at a time is just fine) have a buddy sit in the car while you spin the tire. Have him apply the brake both hard and then steady, alternating a few times while you spin the tire. If there are no problems, your tires should stop smooth and steady each time with no vibration.

If you have noise, vibration, etc.... you found your side. Start by inspecting mounting bolts and a loose caliper will make all sorts of noise. Then check to see if your pads are seating properly and the caliper piston is moving in and out properly.

81c3

Ok, now were making progress... I would be looking at all 4 wheels and checking every fastener for proper torque...

ghoastrider1