1994 Camry Wagon brake problem

[mLaskowski]

I am having trouble finding the root cause of the brake problems on my wife's 1994 Camry wagon.

About a month ago, the brake light started coming on and the fluid level was low, so I figured the pads on the front or rear needed to be changed. I found the rear pads were worn and, amazingly, someone had installed the inside pads at an angle (it wasn't me - we just bought the car 8 months ago). The backing plates on these pads were actually bent.

During the next week, my wife saw the brake light was on again. The fluid level was still at the 'minimum' mark, so I kept trying to add fluid, but the fluid level would never rise.

About two weeks ago, the brakes went out - the pedal went right to the floor, and the fluid level dropped to half way between the bottom of the reservoir and the 'minimum' mark. I checked all the hoses and calipers, but there were no leaks.

Today I replaced the master cylinder and made sure it was bled properly before I installed it. The bottom of the reservoir, the filter screen, and the float for the low fluid switch were full of sludge, which is why it wouldn't take the fluid a few weeks ago. I flushed the reservoir before reinstalling it.

The wheel cylinders on the right rear and left front have plenty of fluid flow when I am bleeding them, but the front right and left rear do not. After good fluid bleeding on the first try, the next bleeds produce very little flow. I am following the sequence listed in the Haynes manual I have - right rear first, left front second, left rear third, and right front last.

The brakes seemed to be working, but when I test drove it, it was still having problems. The brakes do not apply at first, which makes me think I need to adjust the boost rod length and check the pedal free-play. When the car is standing still and I keep holding pressure on the pedal, the pedal slowly creeps down to the floor like hydraulic fluid is bleeding out or seeping internally past a valve. The fluid level in the reservior stays at the full mark, and there are no external leaks anywhere.

Could there be a problem with the boost unit? Could there be an internal problem with the proportioning valve on the firewall? I don't have a good diagram of the hydraulic lines, particularly how the fluid flows through the proportioning valve, so I am having trouble figuring out how the fluid moves through the system.

If anyone can give me some advice on what to check next, I'd appreciate it.

Mark

[Toysrme]

brake light started coming on and the fluid level was low

You're still loosing fluid, or the new master cylinder is bad.


Check the brake lines, master cylinder & the seal between the master cyl & the brake booster.

[mLaskowski]

Originally Posted by Toysrme

You're still loosing fluid, or the new master cylinder is bad.


Check the brake lines, master cylinder & the seal between the master cyl & the brake booster.

No, I'm not losing fluid. The reservoir level stays at the full mark. All the lines, hoses, and calipers are dry. The area between the master cylinder and the booster is dry. I've checked them several times.

Yes, it's possible the remanufactured master cylinder is bad from the factory.

[Brian R.]

If it helps, there is a 1994 service manual in a sticky post at the top of this forum. Download it (if you don't already have it) and see if the troubleshooting guide helps.

[mLaskowski]

Originally Posted by Brian R.

If it helps, there is a 1994 service manual in a sticky post at the top of this forum. Download it (if you don't already have it) and see if the troubleshooting guide helps.

That sounds like it might help. I'll try to download and decompress it when I get a chance. Thanks.

[mLaskowski]

Originally Posted by mLaskowski

That sounds like it might help. I'll try to download and decompress it when I get a chance. Thanks.

The 110MB .rar file took so long to download with a dial-up connection, my computer disconnected from the internet due to inactivity.

A friend of mine downloaded it for me and decompressed it, then burned it to a disc.

The information in the brake section was not much more detailed than what my Haynes manual has. It doesn't have a diagram of the hydraulic system without anti-lock brakes. It doesn't list the correct wheel bleeding order. I actually found one error which tells the technician to test the front ABS wheel speed sensors at 112.4 mph.

Overall, I'm very disappointed in the quality of the manual. It's not going to give me any help.

[mLaskowski]

Originally Posted by mLaskowski

That sounds like it might help. I'll try to download and decompress it when I get a chance. Thanks.

I was finally able to download the 110MB documents. The manual doesn't have much more information than I already have. It doesn't have a hydraulic diagram of a non-ABS system. The troubleshooting table doesn't have much information.

Overall, I'm very disappointed with the quality of the manual.

[Toysrme]

There is no wheel bleeding order...
What exactly are you wanting to be told?