I have been doing a lot of work to my car. It sat for about 1 year and a few months. It even sat with the front brake lines open for a couple of months while I stripped and painted the engine bay. I also used an 86 gxl(had the 4pot brakes) to convert my 88tii abs to non abs.

What its doing.
My brakes were always kinda of mooshy. From the leaky abs pump to the swapped gxl non ABs parts swap. And now after all the time It sat it has gotten way worse. I have since changed the mc twice for reman units. Bench bleed and bleed the system over 10 times. I also checked to see if any of the calipers were seized. They are all in working order although I'm in need of new caliper hardware. Fluid is clean and no air bubbles coming out if calipers when bled. I have not seen any leaks at all and have looked several times. My brakes lines are bf goodridge SS. So that's not the prob. I have also tried adjusting the pedal adjustment nut. When car is off and you pump the brakes they get firm as if they went so bad. When car is started they sink further into the floorboard. Booster 1way valve has been checked. I'm lost of what false to try.

Please help?

Someone enlighten me with some possibilities

 

IMO, the "mooshy" feel was what the engineers/test drivers liked, an intentional decision.

Compared to other cars with similar calipers, Mazda used undersided MC/booster combos, which leads to longer/softer brake pedal (although the stopping power is fine).
You'll solve your issue by putting in a larger booster and MC, the options for which are quite extensive.
I can personally vouch for the setups from an Acura Integra (1" mc) and the Subaru Legacy (1 1/8" mc) as (almost) bolt on upgrades that will drastically (in a good way) alter your pedal feel.

 

sometimes junk can collect in 3 way splitters at the rear of the car or the proportioning valve which won't allow the air to be bled out properly.

other possibilities are new pads on unmachined rotors. if your rotors have a step in them and the pads have not been seated the mush you are feeling is the calipers pressing the pads into the "U" shaped groove and not making much actual contact on the rotor.


when bleeding a system i use a vacuum operated canister(a 2 gallon vacula), it helps pull air out regardless of where it may be trapped, unlike the traditional method of manual bleeding which sometimes won't get to some air pockets.

if the pedal is just mushy it is probably air trapped, if the pedal sinks slowly and gradually then you are just unlucky with junk reman masters.

you may just want to remove the proportioning valve and the 3 way near the rear of the car and clean them out.

 

Clokker
Clokker
Your threads have been very informative and I plan on trying some of your ideas once I get my brakes to feel normal. But current brakes are beyond mooshy. I remember the brakes being way better then they are now. Currently my brakes could not lock up dry rotted bald 215/40/17 tires stretched on a 17x9. They also have crappy response. As if calipers had a slight delay after jumping on brake pedal or somehow apply progressively.

Ben.
Thanks for chiming in.
I will try to feel for pedal sinking slowly.(while car is off right?) I have been told it is possible to get faulty remans back to back and that I should try a new unit. This is a maybe.

It can't be my pads because these pads and rotors were installed together new. I suspect these the least since they are same pads/rotors that worked way better than now when car ran over a yr. ago.

Proportioning valve and splitter... well.. I will try this first. I will remove these and go to town with brake cleaner.

About the bleeding vacuum pump... I know nothing about using these and will be researching a bit to see how it works.

 

with the car on, a bypassing master cylinder will be much more noticable with vacuum applied to the booster.

 

More info that could help identify the prob.

Bleeder valves on the front calipers seem to be in bad shape. I went and purchased a vacuum bleeder. I noticed that bubbles kept coming no matter how many times I bleed the caliper. Did some reading and I have learned air gets through the threads. Well my bleeder valves are super old and are pretty much rusted. The bleeder valves have to be snugged pretty hard for bubbles to not continue coming into the vacuum pumps reservoir. Oh, read about lithium grease around bleeder valve threads and tried it with no success

Is this keeping me from bleeding my brakes properly?

Ben.
The brake pedal doesn't even hold much pressure when car is on, it almost bottoms out immediately. It build a little pressure when it nearly reach the floor.

 

a vacuum bleeder will pull air as well so it doesn't mean it is coming through the line. i just run about a quart through the whole system starting at the RR>LR>RF>LF wheels in order and then checking progress.

keep at it and hopefully this procedure will help get the air out, because it does sound simply like air trapped in the system.

check the reservoir often, if it ever runs low you have to start all over.

 

What if I told you the bleeders are letting so much air through next to no brake fluid is comes out.

 

try cleaning out the bleeder passages with degreaser and compressed air.

if they're that blocked up though then it could be the bleeders or it could be pointing to a restriction somewhere else in the brakes which is where the air pocket is holding out.

make sure you leave the cap off the reservoir also so that it can breathe. my bleeder can empty the reservoir in about 5 seconds so if it is working well it may be creating a vacuum and stopping flow.

 

I went and tried to run a lot of brake fluid by bleeding it in correct order. rears fill up the reservoir pretty quick. Front left does pretty descent also. Front driver however.. Took me a million bleeds(sarcasm, did not keep count) to get the vacuum pump reservoir 1/2 full. Either way the pedal still feels like garbage.

I think tonight I will buy new bleeder valves for all 4 corners. These things are rusted pretty good in the front and I don't want them to be a worse problem in the future.

 

probably a good idea, once they're rusty even if you clean them they will get crapped up quickly again.

 

Faced with your problem and circumstances, I'd junk the whole system and start from scratch.
I'll take your word that the pads, rotors and stainless lines are good, so they can stay.
Rebuild the calipers, it's neither hard nor expensive, use new bleeders and hardware.
Premade hardlines are cheap and readily available at the big box auto stores, I redid my entire front hardlines for @$20.
Tee fittings are also cheap and easy (@$5), if you think yours is gunked up, just replace it.

Considering upgrading the booster/MC?
Well, now's the time to do it.

The point is to arrive at a perfect baseline, you're not guessing what component could be faulty because you just overhauled them all.
With regular fluid flushes and normal pad/rotor replacement you should get years of service from such a setup.

 

I just remade the front driver hard line, it was suspect for leak. Now there its no leaks for sure. I rebled the system the old way with a helper. Still no go.

Clokker. As much as I would like to do what you suggest, I don't think it's necessary. I have bought some brake cleaner and plan on cleaning prop. Valve and rear T. Although if that doesn't work I will probably do what you suggest.

 

When cleaning the proportioning valve. Should I remove the big 22mm bolt and clean in there?

 

Went ahead and took 22mm bolt and spring out. There was a red peice in there that would not come out. I used tons of brake cleaner on it. To be honest it didn't look like it needed it. Either way, I put it all back and bled the system the old way with helper without any success. Still in the same boat.

 

did you put the new bleeders on?

if you leave the bleeder removed, with a rag over the port and press the pedal slowly does it come out steadily?

 

Front bleeders have not come in yet. Waiting on those for right now. About the bleeder install. Can I use any sort of Teflon to keep air from going through threads?

On your question/suggestion. Could you be a little more specific? Am I just looking for fluid to come out as soon at the pedal starts being pressed? At beginning of stroke?

 

i would install them dry, don't worry about the air being pulled through with a vacuum system.

on the other subject, removing the bleeder from the caliper completely opens the passage. just trying to gauge how well the actual port, line and caliper are flowing.

 

I'm wondering...
How many master cylinders and boosters have you had on the car now?
If there was mixing and matching, did you check the MC>booster pushrod clearance?

 

Second booster, original and this one, and who knows how many mc's Ive had. The booster to Mc clearance has not been checked.

My car is original 88tII and all I know is my booster is n/a. Not sure if its s4 or s5. I am using an mc. From s4 n/a.

 

you can check the pedal free play with the car off, it should only be about 1/4" before it starts to feel the slack taken out.

 

Pedal feel is the first wrong thing I noticed. Even though it always comes all the way back up the pedal is dead for about half to 3/4 of the stroke with it finally getting a bit stiff like 2 inches from hitting floorboard

 

Update, with more fail.

I installed new bleeders and I also adjusted the booster/mc rod.

Initially when I adjusted the booster rod(longer) and bleed the brakes, the brakes pedal felt like this was it. I had finally found what it needed.
Before rod adjustment, when bleeding the brakes the pedal would be near the floor and when bleeder valve was opened the pedal traveled no more than 1-2 inches. After rod adjustment the pedal felt better while bleeding- the pedal would travel further when bleeder valve was open during bleeding process. The pedal was gtting firm higher in the stroke and was feeling more normal so this led me to believe I was getting close to fixing. I went to warm the car up to test drive it and while the car was on I pressed on the brake pedal and it sunk fast and easy(not bottoming out just travels too easy).. same crap as always.

 

this really sounds like just another failed cheapo 3rd world country labor rebuilt master cylinder. something to consider is: pedal travel is divided and the first 2/3 of the pedal travel is for the front brakes and the last 1/3 is from the rear brakes, when the fluid can actually compress the springs works against one another and both work nearly equally. you can verify the master cylinder by clamping it in a vice, get some port plugs, bleed it and cap it and then work the plunger, if it even moves more than 10% while pushing it in slowly the master is junk.

 

Why is it when the car was off it felt pretty normal, but when car was on it all felt like garbage.

Also is it possible to over extend the booster rod? I extended it about 3 to 4 full turns. I did not use any tool.