10year7

I think that this is my 3rd post regarding the brakes on my 10 AE

Here is what's happened so far,

Took the car out of storage this spring and the brake pedal was traveling to the floor with the rear brakes locking up under hard braking

Here is what has been done so far;

Front calipers rebuilt

Brakes bled like 4X

Did not change things - even more pedal travel and even worse rear lockup

Leak was detected in ABS pump

was advised by just about everyone to convert the car to non- ABS

Was Converted using non ABS MBC and Mazda hard brake lines

Had some great help from the RXclubofontario - Thank you again Sean and Alvin you guys are awsome

and the car was converted to non ABS

Car was rebled today 3X and although the brake pedal does feel a bit better the rear's are still locking up under hard braking

-Will having the rear calipers rebuilt solve my problem?

-It could not possibly be the proportioning valve could it?

I can't wait to actually get to drive my car again!

Please Advise

RXciting

I'd pull out the rear calipers and make sure the pistons come out smoothly and go back in using an air compressor. Probably goes without saying but make sure to place a 2x4 between the piston and the front of the caliper when removing the piston with compressed air.
If you haven't checked the proportioning valve now might be the time to do so.

Cheers!

Brake calipers fail by binding, meaning they don't retract and drag the rear brakes against the disc.

I would first assume that your master cylinder is taking a dump. You can verify hyrdualic pressure. Check the Factory service manual it explains it very clearly in there. Old master cylinders don't like to be bled since all the dirt and crap goes through the diaphram.

If the master then checks out fine, rebleed the front brakes quickly. Buy some speed bleeders they are the best thing.

If you are still having problems I would hazard to guess it could be suspension related. A blown shock may cause the wheel to flutter under heavy braking causing it to lock.

10year7

Thanks for your reply Cheers

There is a brand new Master Brake Cylinder on the car and the suspension is pretty tight; I put a new set of eibach's on the car last spring

The brakes have been bled several X's but I might try it again

nubian

good to know someone else has **** brakes also, me and chrisNG both have probs, both of us have had the passenger rear e-brake thing on the caliper pretty much seize. i disconnected this and my ebrake works, releases when i want it to. mines at the point were the fuse for abs have been removed. i think chris has done the same. i know he still has his abs box under the hood, i assume hes usin it still because it doesnt leak. mine on the other hand is wierd like yours. i've bled it a few times and air keeps coming out, but i dont lose fluid, ive tripple checked all the nipples for tightness. and still have the same prob. lots of squeling and i know all the pads are good. i will follow your path but start with the rears. hopefully you can find the 10ae plague! also, me and chriss have 10ae's. i know they were built in the mix of all the other 88 t2's, but is it strange that 3 of us have the same prob.... no?!?!? good luck

coldfire

iTrader: (1)

does the car pull to one side under any braking circumstance?

it's wierd that faulty rear calipers would produce MORE braking than the fronts, but it is possible. i would look first that proper fluid proportioning is occuring and all air is out of the system. the FSM actually provides quite extensive pressure measurement testing.

Cheers!

shocks too? or just springs?

10year7

[QUOTE=coldfire]does the car pull to one side under any braking circumstance?

The car does seem to pull a bit to the drivers side

10year7

FSM?????

ScrappyDoo

iTrader: (7)

Factory Service Manual

10year7

Last night my father and I bled the lines comming out of the master and there was air in the system.

I plan on rebleeding the brakes again and seeing what happens.

What sort of tool do you use to check the presure coming out of the proportioning valve and where do I get one.

coldfire

iTrader: (1)

i've only ever done the brakes on my car, so i'm no expert in this area. i can only tell you a few basic things:

- make sure you are bleeding the system correctly; the order for bleeding should be going from the furthest point from the MBC to the closest, so RR (right-rear caliper), LR, RF, then LF. another thing to remember for the rear calipers is to bleed the BOTTOM bleeder valve first, then do the TOP one (they are about 90 degrees apart)

- car pulling to one side: what you should be looking for is a faulty caliper on the side opposite to the direction being pulled, or there could even be air in the lines on the side that pulls. there's also the possibilites of bad pads or rotors on this side.

- testing pressure: this is done to see if the power brake system and proportioning valve is operating correctly. go download the FSM here:
http://www.iluvmyrx7.com/2nd_gen_manuals.htm

there is a specific section on braking that explains all the testing and troubleshooting for you to do. as for what to test pressure with (not really mentioned in the FSM), you need to get a special "brake line pressure testing" kit. i think they are expensive so try to borrow/rent one.

hope that helps

10year7

Bled the system again,

Does not appear to be pulling to one side anymore but there is still excessive pedal travel with rear lockup, and there does not appear to be air in the system, and I can not find any fluid leaking- WTF.

Does anyone know of a good honest and relatively inexpensive mechanic in the burlington area that can help me out.

I don't feel like paying the Mazda dealer to troubleshoot and repair this problem.

ScrappyDoo

iTrader: (7)

Mark, you have all new lines,MC, rebuilt front calipers and fresh fluid. You only have the rear calipers left to rebuild, may as well bite the bullit and do it. I highly doubt it is the proportioning valve.

StarScreaM2k1

i think i have a spare proportioning valve somewhere in the garage...

23Racer

Guys, I had the exact same problem with my car at the ALMS race last year. No matter what we did, we couldn't get the pedal to come up. The problem is that with the Mazda Proportioning valve you have to be extremely careful when you first start bleeding the brakes. It is very easy to shove the shuttle valve all the way to one end of the proportioning valve and after that, no matter what you do the brakes will not bleed properly.

I corrected it using the following bleeding steps:

1) First a small series of taps on the proportioning valve to release the shuttle valve while you have someone "SLOWLY" depress the brake pedal a few times.

2) Start at the passenger side rear and bleed each caliper one time (one pedal throw). Slowly crack open the valve as well and leave the pedal at the floor until you shut the bleeder valve. Sequence - Passenger Rear, Drivers Rear, Passenger Front, Drivers Front

3) Repeat a number of times (it took us about 4 circuits) until you start to feel the pedal firm up. Then bleed the front calipers until hard.

The main issue is bleeding the whole system at the same time to prevent the shuttle valve from being driven to one end. Continually bleeding an end that is full of fluid seems wrong, but is done to ensure that the shuttle valve in the proportioning valve remains in a position to allow fluid flow to all circuits. This is a safety feature from Mazda to ensure that the car has some brakes after a catastrophic brake failure at one end of the car.

The main thing to do is to depress the pedal slowly, while you are bleeding the brakes. Many times I have and have seen other people pound away at the brake pedal like it is an Olympic sport. This technique results in fluid cavitiation and the generation of air bubbles as well as the messing up of the proportioning valve. Slowly, firmly, steadily and for a long time works best when you are bleeding your brakes and in other things as well.

Just some advice from someone who has bled the brakes on racing and street cars about 4 million times.

10year7

If you do have a working spare proportioning valve can you bring it to the meet tonight? Or give it to someone who is attending.

I will PM you.