Replace Brake Booster/Master Cylinder Gasket

[PaulR162]

Hi everyone,

I have a 1999 Camry Solara V6. I know there is a Solara sub-forum here but it doesn't seem to get much attention any more, and I think the parts the same on both the Camry and Camry Solara.

I am having an issue with the brakes being weaker than normal and the car wanting to move at a stoplight unless you really down the pedal (I know this is normal for Toyotas, but it's worse than normal). I did the tests for the brake booster and found that it is not holding air correctly when I do the tests. I also hear a hissing sound when I turn off the car, don't know if that's related? Before I replace the entire brake booster, I saw that some people on this forum simply replaced the brake booster to master cylinder gasket. I have a Haynes manual, and it doesn't provide instructions to replace the gasket, only remove the brake booster. Can I remove the two bolts that hold the master cylinder to the brake booster, slide on the new gasket, and bolt it back in without messing with the brake lines and bleeding the brakes? If so, is there a special grease I should use on this gasket?

Thanks for your help in advance.

[Mister_Perkins]

The Brake Booster Simply has a Plunger Style tube that extends out, and pushes the fluid through the brake lines. You will be fine disconnecting the master cylinder. Just make sure you dont try to adjust the Push-Rod on the Booster. It's right where it needs to Be!

[PaulR162]

Originally Posted by Mister_Perkins

The Brake Booster Simply has a Plunger Style tube that extends out, and pushes the fluid through the brake lines. You will be fine disconnecting the master cylinder. Just make sure you dont try to adjust the Push-Rod on the Booster. It's right where it needs to Be!

Thanks for your help Mister_Perkins. I don't disconnect any of the brake lines, just unhook the two bolts and take out the old gasket and slide in the new, correct?

Thanks again.

[Mister_Perkins]

I am thinking that Removing the Master Cylinder will not fix your problem to tell you the truth.

Theres No gasket Behind the Master Cylinder. All it has is a plunger that pushes inside of it. What you can check for it Leakage on the inside of where the booster and MC fit together. If you have fluid there, you will likely have to rebuild or replace the Master Cylinder.




Heres a link for a rebuild kit for it. Its probably $20.00 - $30.00 shipped
http://www.rockauto.com/catalog/rafr...483480-7182771

[PaulR162]

Thanks for your response. Below is a picture of the gasket that I am going to replace (and I believe is where the hiss is when I turn off my car). From some online research, I understand that this gasket can go bad causing the problems that I am experiencing. Do you think that this gasket could cause those issues?

[Mister_Perkins]

I dont think so, but if you remove the Master Cylinder, you will at least be able to see behind it. Gaskets are inexpensive so its always worth a try anyways


More than likely you might have some problems once you remove the bolts on the MC. You are going to have to slowly bend the brake lines to remove the MC enough to replace the gasket.

Just make sure you dont Kink the lines or you will be in a world of trouble. It's actually not too bad, you will just have to Cut the kink out, and add a compression union in its place.

[fenixus]

actually there IS a paper gasket between back of master cylinder and front of the brake booster assembly


more info here (gen4 1mz-fe):
DIY Master Cylinder replacement (1mz-fe / others similar) *PICS*

[Mister_Perkins]

Yeah I forgot about that gasket. I should have remembered it too, considering that I just had the Mastercylinder / booster off of the car back in september. hehe

[PaulR162]

Thanks for your help Mister_Perkins and fenixus. I ordered the gasket from the dealer today (costs $1.26). I will replace it next weekend and report back with the result.

fenixus, that is a great tutorial that you posted, and I will be using it in the event that the gasket doesn't solve the problem! Do you happen to know if that gasket itself can be removed without disconnecting anything else besides the bolts (and the strut bar/air cleaner and whatever else covers it).

[JohnGD]

An old gasket can cause vacuum leaks and hissing sound. But if there is a vacuum leak you'll end up with a hard pedal. Is this the symptom?

Weak brakes have other causes. As mentioned the problem may be with the master cylinder. If the rear seal fails the brake fluid can leak out from the back and into the booster.

So when you say "really down" on the pedal is the pedal really low in order to get some stopping power? If so you may have a worn piston seal inside the master cylinder or air in the system.

If you pump the brake pedal does the height rise? If so there air in the system. Otherwise a worn seal means you need to do what Fenixus did.

Fenixus' photo showed internal corrosion damage. That's why it's good to flush out the entire brake system every 2 years with a low moisture activity fluid like Valvoline Synthetic DOT 3/4 or Castrol GT LMA.

The only thing is I'm not sure if you can clear the bolt studs without removing the lines. Not sure. But the gasket should seal the vacuum leak between the master cylinder if there is no major surface defect from corrosion.

[PaulR162]

I wanted to provide an update to this issue. Yesterday, I replaced the master cylinder to brake booster gasket, and it appears that the issue has been fixed. My old gasket looked worse than the one posted above. I was able to remove the air intake assembly to the throttle body, and that gave me enough room to work. I just unbolted the two bolts to the master cylinder, and I was able to maneuver it enough to clean the mating surfaces and install the new gasket without removing any brake lines or anything else. I just wanted to confirm that I didn't need to adjust the brake booster pin because I didn't actually change it, correct?

Thanks for all of your help everyone, I really appreciate it!

[Mister_Perkins]

Glad to hear you got the problem solved

[fenixus]

nice

and yes, simple gasket replacement shouldn't call for the push rod adjustment if there was no problem with it to start with. actually even replacing the master cylinder with a new OEM part shouldn't call for such adjustment.