Nave43

Thanks Tyler i will look up some stuff online and see if i cant rig something up. From your posts i am also becoming a firm believer in there simply being stubborn air in the system. Did the pedal firm up after hitting some bumps or anything?

Welcome to the club my friend, this makes three of us with the EXACT same problem. Ide start with the things stated above.

New Brake fluid and do a thorough bleed- I suggest Valvoline synthetic Dot3-4 its cheap but quality, if you drive stick do the clutch while your at it. Just make sure not to introduce any new air into the system.

Clean and re-grease all calipers slide pins (Not sure about how the drum brakes work) Most importantly use "Sil Glyde" lubricant almost anything else will destroy your calipers dust boots...

Make sure the person you bought the car from installed the calipers on the right side of the car... sounds dumb but it happens (there is either a L or R on the caliper to distinguish what side it belongs to)

Check all your brake hoses for bulging, or wear... i dont believe your S model has SS (Stainless Steal) brake lines so that could be a weak point in your system.

Run trouble shooting on your brake booster to make sure it functions correctly, If you dont know how a "Haynes Manual" will be a worthy investment if you plan on spending any time with the car.

Finally make sure your MC (brake master cylinder) is torqued to spec
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Everything above shouldn't cost you more than 20$
If after all that you still have the same problem, we are one the same page and maybe we can work through this together...

I on the other hand am cleaning and re-greasing my rear slide pins tomorrow. (because i had to re-do the fronts today due to not doing it right the first time) If that offers no improvement. I am going with the new MC as Ron J suggested, but instead of buying another 13/16MC (Stock) I will be purchasing a larger 7/8MC because it will reduce my pedal travel and bolt onto the stock brake booster and lines with no modification.

hwyix

iTrader: (1)

This ^^^^ of course after you bleed the at least 10 times first. Which you already have. So the next step is the MC.

Volatile

I also have the same issue, when I purchased the car driving on the highways never noticed the brake issue, but when I drove on some hills during the weekend and had to brake, it would sink slowly but surely unless I let go of the brakes and it stops at the top then repeats the process.

Do any of you guys use your Emergency Brake as a temporary solution as you solve this? Is it recommended not to? Thanks guys.

Former User

Dude, please fix your brake problem before you drive your car again. Otherwise, you may die in a crash, or worse, kill somebody else.

Volatile

Completely understandable. The brake system has not given me any problems with a normal brake ((such as driving and lowering speeds.)) It's simply when I'm idling while holding on the brake.

Mines does some sort of gargling sound (?), so I should look more into that.

Former User

Gargling while idling? Why do you think this would be a brake problem?

Volatile

Well, idling as in turned off completely as the sound is subtle. We checked and traced the noise to where the MC/Booster is where it seems like there's air in the brakes or something.

As I said, the brake problem is barely noticeable as it's only on hills and on Standby. ((So far I've never had to floor the brakes for it to function.)) So I'm not completely aware of the issue until today.

Former User

You've lost me, and I'm not easily lost. If you have anymore questions on your post, please create your own thread. Otherwise, you're threadjacking.

Volatile

I'll try to get a better description when I check out the car tomorrow. Sorry for the threadjacking. Hope the problem gets fixed for OP/Others.

Nave43

Do you really consider it thread-jacking if we are all having the exact same problem? I personally am amazed by how many people have this problem. Really makes me wonder... This is like the fifth person with the exact same problem.

Stay tuned on this thread OP im trying to get the flow together for a new Master Cylinder. If it doesn't help me then its not the problem... Many other have replaced the MC and still have the problem so i am suspect about that being the solution... I personally suspect the mushy pedal part has something to do with the prop valve.

Also i never updated but i re-greased the rear pins. Didn't help in the slightest...

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Tyler Dirden gave me an idea though

Take the cap from a MC and cut a hole in it. Put a bike pump in that hole and silicone it around it. Then fill up the MC and screw on the cap. This could in theory force brake fluid through the system from the MC side and force out any air that could be stuck in the squiggle of brake lines on the fire wall. Or the prop valve. You would have to open the bleeder valves like usual but it would squirt out at pressure. Haven't got the materials together to try it. Just an idea that i thought i would share.

While doing this you could lift up the brake calipers like you do when you change your brakes to get the bleed valves straight up as possible. Then put a piece of wood in between the piston and outside of the caliper so they wont extend either. Letting any air that could be stuck in the calipers out as-well. Hopefully you understood my description.

/\ This wouldn't help with it falling at stops. Though it may benefit if you have a mushy pedal between were it drops to at a stop, and the floor like me.

Former User

Most members don't want their threads jacked, but Nave doesn't seem to mind. So, feel free to post your brake problems here.

I'm less amazed than you. It's a car forum. Brake problems are not uncommon. And as I've said, I don't think your brake problem is anything out of the ordinary. Let's see what happens when the MC is replaced.

Nave43

Long time with no updates, but i finally replaced my old worn out 13/16 MC with a new 7/8 MC. After a good bleed while i still have excessive travel and a very squishy pedal. The sinking sensation in the pedal has been corrected.

This leads me to believe that the old MC was indeed faulty but wasn't the sole contributor. Next step at this point is to check my pedal free-play and make sure its within spec. Depending on how that goes maybe take the MC back off and do a push-rod adjustment. Then bleed and bleed and bleed....

Former User

Bench bleed the MC and then re-bleed the system.

JarvisW

I had a problem of the pedal going slowly to the floor, I changed the check valve in the pic above, and that fixed that problem.

Like $20 at the dealer, parts stores don't carry our type.

Nave43

Sorry i didn't mention it before but i did thoroughly bench bleed the MC with return lines prior to install.

I am guessing your referring to the brake booster check valve? Last i checked mine was functioning correctly but its been awhile and never hurts to double check.

Nave43

Another update i plan to keep going until its solved.


I tried engaging the E-brake and seeing if that changed pedal travel. It did not, meaning my problem is not free-play in the rear pads.

I bled the system 3 more times with the 2 person method. I DID get some air the first time around, the two consecutive bleeds after that didn't seem to help.

The pedal is slightly firmer now but can still easily be squished to the floor.

The strange part is that at highway speed the pedal feels very far up, braking begins about an inch down (Normal). Sometimes it will remain that way while stopped, other times not, the friction point will fall to the usual 2-3 inches down. Braking and mashing the brakes at speed (40 MPH) causes serious fade and after one good stop the brake will be back to there usual 2-3 inches from the floor. Driveling at speed again it will recover but it takes awhile.

Broskiballa

OP - you mentioned that when initially flushing your brake fluid, it came out dark and grimey. (old fluid from the sound) I wonder if this old fluid was aiding your old o-rings/ seals in your MC. When you flushed with fresh fluid, this might have clear the grime within your brake lines adding the the 'mushy' brake feel.

I would highly suggest you replace your MC. Sounds like an old MC that was forcing dirty bad fluid for too long.

Former User

Again, just standard operating procedure. You'll lose less time by not overcomplicating every issue you have.

Nave43

MC was just replaced with a new 7/8th master. MC was thoroughly bench bled, and the brake fluid has been bled 3x since then with Valvoline Dot 3-4 fluid. Nothing but golden fluid in these lines.


Push rod free-play seems to be within spec, only thought this might be a problem because of the larger MC. Thusly my updates are for anyone who comes back to this thread. Its a very common problem and lists of items i trouble-shoot doesn't seem entirely unethical...

belairbrian

Are the break hoses original 93 vintage? If so they may be giving a bit.

What sequence are you bleeding the brakes in?

When I bought my Del Sol a couple years ago it had what certainly appeared to be all OEM brakes except of course the pads. They worked pretty good, but realizing they had 20 year old rubber parts, I swapped out all four calipers, all four brake hoses and the MC.

Former User

Where did I accuse you of being unethical?

What I am and have been trying to say in this thread is that your approach is bassackwards in terms of efficiency. A common problem is just a common problem until proven to be something else. For reasons unclear to me, you decided very early on in this thread that your car problem was something out of the ordinary and, as a consequence, abandoned all the obvious possibilities. I'm taking time to point this out because if you stay on this track, diagnosing and solving car problems will always be a long and arduous task unnecessarily. However, if that's your chosen path and you're sticking to it, then so be it.

Nave43

You never called me unethical. Text makes it very hard to read tone, leaving things in translation. Regardless thank you for ALL your help. I am aware im not the most efficient but i thank you for your patience and understanding and whatnot. Im trying to learn and get better hence why i am here so often. I dont just want to know "its broke get a new one" I like to know why and how. So i really dont mind working backwards if that makes sense.

P.S. Bring me back to K-PAX when you leave.

RR - FL - RL - FR , 2 Person method w/ jar of brake fluid and tube to nipple.

Calipers are original but have been well maintained. Pins and pistons all move freely with no uneven pad wear, or fluid leakage. Stops in a straight line with no pull.

Hoses are also original and are in line to be replaced. No bulges or scabbing but it couldn't hurt. ("In-line" get it? )

Next step is to try something i read on an integra forum. Compress the piston while bleeding at the nipple, with the caliper nipple rotated straight up. Apparently air can be trapped in the piston, that cant be bled with conventional bleeding. It can also be a problem in motor cycles were you have to remove the caliper and bleed it at a very specific angle to get an effective bleed.