Brake problems.

[Chip Bacarisse]

I have replaced the frt left caliper and the brk hose. But I still had a issue with it locking up. My pedal got hard to8 press and when I got out of the truck you could really smell burnt brakes. I have a 2007 chevy Silverado classic LS with a small V8.

Do I need to replace the MC?

 

[C1]

I wouldn't think so. Your issue sounds like the classic problem of caliper piston binding in its bore.

You probably have a mess now : Warped/burnt/glazed disk rotor due to over heating; possible damaged caliper; overheated wheel bearing axle grease.

Pull the whole thing down, clean it all out and reassemble ensuring all parts work as designed.
- Check wheel bearing grease; clean, repack, re-assemble as needed
- Send rotor to shop for inspection, turning & surface hone (to obviate pad wander - eg, classic phono groove effect)
- Disassemble caliper and inspect; clean bore (lightly sand if necessary) & piston; rebuild/reassemble with new piston ring seal (probably the most critical component); new dust boot if necessary
- Grease arbor rails
- De-glaze break pads (if necessary)
- Reassemble system and inspect to ensure no binding of caliper on arbor
- Fill and bleed caliper
- Test system

For testing I usually first do a manual spin with the wheel jacked up off the ground to ensure that the piston retracts properly after applying pedal. (The wheel should spin freely by hand & not drag. Any drag should be only slight which is normal.)

Then I go for a short test drive a bit using the brake.
Then stop & let the brake wheel cool. Then I do a highway test.

This involves not using the brake (ie, keep the wheel/rim cool). Drive for five miles or so at high speed. Pull over not using the disk brake, use emergency instead, then feel the hubs of each of the disk brake wheels. They at best should be near ambient temperature. If they are too warm, then that tells you that the calipers are dragging pads on rotors (piston not retracting properly) & you will need to rectify the issue with whatever it takes.

Good luck (been there done that)

PS: It is always best to keep your OEM calipers and rebuild them if necessary as replacing them with rebuilds can be problematic. Rebuilt calipers simply can have configuration and/or tolerance issues. These can be subtle (eg, some hard to detect issue with the caliper casting) and the calipers will just not work well with your vehicle.

 

[RLGL]

Possibly a collapsed brake line, are you able to get the piston of the caliper to retract manually? If not it may be the rubber brake line is collapsed.

 

[Chip Bacarisse]

Possibly a collapsed brake line, are you able to get the piston of the caliper to retract manually? If not it may be the rubber brake line is collapsed.

Put a new one on when I installed the caliper.

 

[Chip Bacarisse]

I took the Master cyl off and found fluid in the booster. What do I do now?

 

[C1]

It used to be that you'd go to an auto parts store and buy a rebuilt booster & it came with a MC attached.

Rebuilding just a MC used to be real easy (replace plunger & seals contained in a rebuild kit; didnt even have to remove the MC from the booster), but now since you have brake fluid in the booster that will damage it. (Sounds like the first MC plunger seal that keeps fluid from seeping out of the MC is gone.)

So just replace the booster & MC (shouldnt be that bad).

However, given all that has happened, you probably should have the whole brake system pulled down & inspected (drained & refilled too) by a competent shop specializing in brake servicing and repair.

 

[AKACyrano]

If

It used to be that you'd go to an auto parts store and buy a rebuilt booster & it came with a MC attached.

Rebuilding just a MC used to be real easy (replace plunger & seals contained in a rebuild kit; didnt even have to remove the MC from the booster), but now since you have brake fluid in the booster that will damage it. (Sounds like the first MC plunger seal that keeps fluid from seeping out of the MC is gone.)

So just replace the booster & MC (shouldnt be that bad).

However, given all that has happened, you probably should have the whole brake system pulled down & inspected (drained & refilled too) by a competent shop specializing in brake servicing and repair.

it has ABS, probably< it would have required

 

[AKACyrano]

If it has ABS, probably, it would have had to be connected to a factory scan tool to be bled correctly.

 

[JCH13]

I have replaced the frt left caliper and the brk hose. But I still had a issue with it locking up. My pedal got hard to8 press and when I got out of the truck you could really smell burnt brakes. I have a 2007 chevy Silverado classic LS with a small V8.

Do I need to replace the MC?

Need much more information for a helpful diagnosis. Is the front left the corner that is getting hot? Did you grease the caliper slide pins when you installed it?

I don't think that a leaking MC would cause any sort of brake binding. It would generally cause the opposite!

Possibly a collapsed brake line, are you able to get the piston of the caliper to retract manually? If not it may be the rubber brake line is collapsed.

Put a new one on when I installed the caliper.

If you twisted the line during installation this can be an issue. Line pressure will get through the twist, but not allow the pads to relax, causing the overheating that you're seeing.

If it has ABS, probably, it would have had to be connected to a factory scan tool to be bled correctly.

Not always true. See: http://stoptech.com/technical-support/technical-white-papers/bleeding-abs-brake-systems

 

[Squisher]

Speaking of caliper slide pins, another thing that can cause brake binding is a wear ridge on the caliper holder where the two ears that extend out of the pads ride/touch. When doing a brake job looking to see if there is a ridge where a previous pad wore on these surfaces and then grinding the ridge IF it's present smooth is a good idea.

 

[mindless1]

^ IF I understand what you're suggesting, this would apply to older braking systems while by 2007, GM used calipers where the pads ride on abutment clips, not directly on cast in rails, that would be replaced if overly deformed or corroded, just thin sheet metal with no ridge to file down. Many brake pad sets come with new ones, though if the old clips look okay it is acceptable to clean and reuse them if you *need* to.

Something odd is going on with this topic. One wheel locking up is not a cause to pull the master cylinder. As JCH13 mentioned, if there's a problem there, if anything it would cause loss of fluid pressure. What led you to the conclusion that the master cylinder should be pulled off?

Chip B, you wrote that the pedal was hard to depress, another sign it wasn't leaking, at least not badly at the time of appling brakes. Was the fluid reservoir low without any other source of leaks?

You replaced front left caliper and hose but if the brakes were locking up it is likely it needed replacement rotors and pads too. If you did replace them, it can be normal for the pads to outgass a little while breaking in and smell a bit. Pedal hard to press could just be that you're comparing the now bled system which works as it should while previously there was air in it.

I feel that there is some information from the OP missing in this topic.