Rebel 1

I recently had the revised clutch master cyl. put onto my '09 with 12,200 miles at a local dealer. Even though i had complained before about this potential problem and safety issue concerning the clutch master cyl., the service manager was playing hardball not wanting to replace it. After some time of back and forth he agreed to foot the labor for the job if i bought the new clutch master cyl. so i did. When they called to tell me the car was ready, they Also told me the brake master cyl. was leaking into the booster and wanted to charge me $575.60! to replace them including labor. When i went to look at what he was talking about, the mechanic had already bolted the brake master cyl. back to the booster. I don't know why he unbolted the brake master cyl. to install the clutch master cyl. in the first place.
My brakes have not changed since i bought the car and the brake fluid level is about 1/4" below MAX FILL.
I would like to unbolt the brake master cyl. from the booster to see for myself. Can the two nuts be removed from the brake master to pull it away to look into the booster without disturbing anything else? I know there is a pushrod that goes into the brake master cyl.
Thanks for any help.

Dano523

The rod that goes into the brake master cylinder is part of the brake booster,which the rod is part of the diaphragm of the booster. So if there was problems, the fluid would not be begin into the booster, but leaking down between the booster and where the master cylinder come together instead.

Also, if there was a leak, then you would know about it, since the fluid in the brake reserve tank would be leaking a hell of a rate too.





If the booster went out, then you would be able to feel this as well when using the brakes
http://www.corvettesalvage.com/index..._image&pID=490

But, if you want to remove the cylinder from the booster, then you can do so. But with no major leak from the tank, what sounds like is fluid from the tank that may have over flowed out the cap from the tank being too full, and what may have flowed down the outside out side of the booster out surface isntead.

Post a photo of where the paint is coming off the booster and would clue us in better if there is a leak in the master from the start.


Also, really shady for a tech that knows what he is doing on the vet to even go near the master brake cylinder in the first place to replace a clutch master cylinder. To get to the clutch master cylinder, you go through the drivers side front tire, back wheel well cover access plate instead. Hence once you have the pin removed from the pedal, you turn the master cylinder to release it from the fire wall through the wheel well opening, then reach back through the same opening to disconnect the middle coupling link apart.



To add, if the master cylinder is leaking out the back end, they make a new seal kit to rebuild the master cylinder for about $30.

Dano523

You have to ditch photo bucket since they want money now to host photos, and use something like Imgur instead.
Hence your photo is not showing up.

When you sign up for the Imgur account to host photo's for free , just remember to set your photos in your photo albums to private!!!!

Also, notice that the brake master cylinder does have the bottom V slot, so it it does start to leak and your having to keep filling the tank to keep it full, it's a dead give away where it leaking if from the back of the master cylinder.

Hence as the brake pads wear, this will take up some of the tank fluid, and you will need to add a little to bring the fluid back up to the full mark over thousands of miles.

If the master is leaking each time you go to use the brakes each drive, and you are having to top off the tank between drives of the vet each time, then that would be a leak problem that needs to be resolved isntead.

If you can post a photo of the booster that will show up, then it's easy to tell if the leak was coming from the V slot on the back of the master, or if from the tank cap with the tank over filled, by where the paint is starting to flake off the booster isntead.

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But lets digress a touch, and the brake fluid in system should be powder flushed out every two years since it will pull the moisture out of the air to collect water in the fluid, which lowers the boiling point of the fluid.

So if the fluid in system has not been power flushed with new fluid in the system since 09, then would dare to guess that the fluid has collected so much humidity out of the air, that the boiling point in the fluid is so low now, that it would not be hard to boil the fluid with just the mildest of sprinted driving instead. Hence with the fluid to the full mark, it boiled, then fluid would be coming out from the cap, sprayed back to the to booster, and what may have been showing up on the booster isntead.

Dano523

If your master was leaking, there would be no paint left on the booster below the cylinder (to the right of the white label and down where the numbering is stamped on the booster.






As for power bleeding the brake system to get all the old fluid replaced with new fluid.


Step one is the brake reserve tank is drained of all the old fluid, a lint free rag is used to get all the crap out off the insides of the tank, then it filled with new fluid to the full line.

Step two, power bleeder unit is installed on the tank to pressurize the tank to 15lbs, then the passenger side rear caliper bleeder is opened to allow the new fluid to drive the old fluid out to this caliper. Hence what we need to begin with, is the fluid from the tank, to the ABS module to be exhanged with new fluid to this point in the system.

Step three, with at least the fluid from the Tank to the ABS unit now new clean fluid, we use a Tech II tool to do an auto bleed on the system. What the tool will do is cycle not only the ABS pump, but the abs valves to drive the old fluid out of them, replace it with the new clean fluid from the tank, with the old fluid driven farther down lines towards the calipers.

Step 4 now that the fluid in the tank and the fluid in the ABS pump has been replaced with new fluid, we go back to the rear passenger caliper to use the power flush unit again to drive the last of the old fluid out of the line until clear fluid flows from the bleeder and it closed again. From this point, we go to the driver rear to power bleed until the fluid flows clear for it and close that bleeder, followed by the the passenger front caliper, then the drivers caliper last.
Note if we are just using an air type pressure powder bleeder unit, then between each steps, we go back to make sure that the fluid in the tank is refilled to the full line again. Hence we always want flesh fluid pushing out the old fluid, and at no time the tank empty and pushing air through the lines isntead.

So simply, we are using a power bleeder kit so the new fluid in the tank drives the old fluid out, as well as cycling the abs Pump and valves once we have new fluid to them via the tech II, so that fluid in the ABS parts are exchanged with new fluid as well.

As for gravity bleeding, not enough pressure to make sure that all the old fluid is drive out, and if you don't cycle the ABS pump to get the fluid out of it, then you still have old fluid in the abs unit that will mix back in with the new fluid after the bleed. And don't buy that you don't need to cycle the abs pump with a bleeder valve open, since trying to flush the pump which driving recklessly to activate it, will not end up with the pump flushed completely with new fluid, since the pump will not cycle long enough, nor push all the old fluid out of it as well (old fluid has no where to go).
So if you are doing powder flushes even 2 years, you may get by with not having to cycle the abs unit, but with fluid being close to a decade of moisture and rubber seal debris collection, you do want to power flush the system, including cycling the ABS system as well.

As for power bleeding the system to replace all the old fluid completely (including ABS cycling with Auto bleed steps), only takes about a quart of new fluid, even with all the above steps.

Dano523

2oz of fluid lose would be showing up in the tank loss.

If you have the old cylinder on hand, remove the back C ring, and pull the inner plunger seal assembly out of the body, then look at the seal assembly for tears or voids in the seals (back O ring and V seal, or forward V seal on the plunger housing) that would cause leaks past them, and the channel of the body for a deep groove on the back side that would allow an oil leak past them.




Hence still not sold that the Master was leaking to begin with, and that the dealership did not flood the booster with fluid when they pulled it off isntead.