CGTSX2004

iTrader: (1)

So I took the car in today to have the oil changed and to have the brakes inspected. For the last couple weeks (since my 1000 mile trip to Boston), the brakes have been mushy and unresponsive. I have avoided driving the car as much as possible. As it turns out, the master brake cylinder is leaking fluid.

They're fixing it under warranty (as they rightly should).

I was highly annoyed with the service rep though when he tried to insinuate that by changing the brake pads and flushing the brake fluid, I might have somehow caused the problem.

Anyhow, the part needs to ordered (I think they're over-nighting it) and I'm going to get it replaced as soon as the part comes in.

With all the Acura cars that my family has owned, the TSX has been the only one that has had a problem with the brakes on this level.

dom

First we've heard of this problem?

Maybe it was you Or did you have Tinky help you with the install?

moda_way

Interesting. Since I did my flush and brake line install, I haven't had this issue at all. I'll be watching close though. You did you Honda fluid on your brake flush, right?

jlukja

CGTSX2004

iTrader: (1)

No, I used an aftermarket DOT 4 fluid. I asked the technician working on my car if that made a difference and he confirmed that it shouldn't matter at all.

moda_way

This was something I did a little research on and found the following:

DOT 3 has a wet boiling point of (140 C / 234 F)
DOT 4 has a wet boiling point of (155 C / 311 F)
- so DOT 4 looks better, however...

DOT 3 has vicosity of 1500 cp (at -40 C / -40 F)
DOT 4 has vicosity of 1800 cp (at -40 C / -40 F)
- so being a more viscous solution would mean it could (possibly) by-pass seals under pressure. On top of this the Honda OEM is supposed to be a heavy duty DOT 3.

Eventhough the mechanic said it should be okay, I've wondered if that is true. I'm not questioning your use of DOT 4, but I do find it very interesting and wonder if there is a deeper correlation.

CGTSX2004

iTrader: (1)

Interesting point, but you'll notice your viscosity figures are at sub-freezing temperatures, which is highly unrealistic given that the temperatures under the hood are probably well beyond 100ºC.

Plus, I only did the brake fluid flush at the beginning of last month so for it to have gone bad this quickly seems rather odd.

moda_way

Agreed, it would seem odd to happen this early.

Question, what was your mileage at failure?

97AcuraCL

somethings up with the 'cyilinders' acura puts in their cars... i've had 2 master cyliners put on the clutch on my car in its 50k mile life.

moda_way

Also, in any case the DOT 4 is a more viscous solution, so would the pressure on the seals increase to cause fatigue. In the manual it states to only use DOT 4 as an emergency procedure, to be replaced by DOT 3 as soon as possible. Again, not faulting you, but I find it interesting to figure out what is the result failure. Will the mechanic be able to tell if a seal failed?

moda_way

Honestly, I've not heard of this issue very much in most Honda's so long as the fluid is maintained. 50k is too frequent as well for 2 replacements.

Bill Hook

FWIW, If you do a "buddy bleed" on the brakes and have a friend pump the pedal, you may very well blow the MC by pushing the piston further than it normally travels and getting it into a rougher area of the cylinder bore that degrades the piston seal. Best to only push the pedal 2/3 of max travel when bleeding.

Bill Hook

I've been using Valvoline Syntech DOT4 for 75K miles and have no issues w/ the MC.

palidanx

how many miles do you have on your car?

moda_way

Cool. I was hoping we had some folks on with something other than Honda OEM stuff. I was considering DOT 5.1, but that stuff evidently is a No-No for our cars.

You'd think something that has a higher viscosity would be okay... but that is merely an assumption on my part.

TinkySD

JTso

iTrader: (2)

I've always used Volvo OEM DOT 4 brake fluid for brake and clutch in all my cars (Honda, Toyota) without any problems. I did have a clutch MC failure on my AE86, mainly from old age. Why I used Volvo fluid? Because I get them for free.

Bill Hook

I believe DOT 5 is the bad stuff (silicone based), not 5.1.

fanbanlo

I'm wondering if my tsx has a bad master cylinder too... but my car is new (4 days old...).

The break doesn't seem to be very sensitive, and I gotta step quite deep to slow down the car. Also, when light press, can definately hear sound of air/gas. Is this normal for the run-in period? Or should I get it checked?

CGTSX2004

iTrader: (1)

28,000 miles. The dealer took care it under warranty and replaced the brake fluid with OEM. We'll see how things go for a while and if all looks good, I may switch it back to the DOT 4 fluid.

Bill Hook

2 things: first, step on the brake pedal while idling; if it sinks (gradually, over a minute), the MC is bad. Second, turn the car off and pump the brakes to get rid of the emergency vacuum reserve, then turn the car on with your foot on the brake; if the pedal sinks, the vacuum booster is working correctly.

fanbanlo

Thank you! btw, what is the vacuum booster for?

Is there anyway to improve the sensitive of the brake? Maybe I'm not used to the brake of TSX yet.. but it does take more effort to stop than my previous cars.

Bill Hook

Feel how hard the pedal is after you pump it w/ ignition off; w/o the booster, that's how your pedal would always feel - not just firm, but like a rock. Personally, I like firm brakes, but not unboosted brakes. Your problem sounds like an issue w/ the booster.

thiro

I just took mine into the dealer this morning and the service guy is the best and very helpful. In 10 minutes they said it's a leaking fuid and bad master cylinder and gave me a loaner car.

The service is great if they have washed the loaner car it would have been icing on the cake.

kaikai114

sounds like a problem i'm having as well.

i have to step on the brakes nearly half way to feel them start to work, is that something to do with the booster or master cylinder?

KC

moda_way

What year TSX do you have again? I changed out my pads, fluid and lines at ~30k miles. The fluid was very dirty and I got a significant improvement in braking again after this. May be nothing at all to do with the master cylinder.

humperdood

If the master cylinder was leaking, you may want to check your paint because if that stuff gets on paint, it will eat right through it!

kaikai114

it's 2004, previously when I had dealer replace the pads, same feeling was there, still have to press the brake half way to even feel the car start slowing down. actually i've had this "half way" feeling ever since i got the car, just thought it was normal... It's more of an "on or off" feeling. what are the immediate symptoms of a malfuctioning master cylinder or booster?

KC

mg7726

the first thing you should do obviously is to check your rotors/pads, then bleed the system. for symptoms of a failing master cylinder, http://autorepair.about.com/cs/troub...g/a/bl302a.htm - i'm too lasy to type it out.

moda_way

Simply put... Leaking. Check for leaking fluid and a lower fluid level.

Acura isn't going to flush your break fluid that early which is why doing what mg7726 suggested.

kaikai114

I'm gonna do the bleeding/flushing tomorrow and new rear hps pads to see if that give an improvement. Is bleeding same as flushing out the system, only that you keep adding new brake oil to the reservoir until it's clean?

KC

ps. is the rear pad install similar to that in the front?

xizor

you're on the right track, bleeding just gets air out of the hoses, flushing means you keep pouring fluid until all the old stuff is gone, and then you bleed the air out.

btw, its brake fluid, not oil

and the rear pads require a special tool to retract the caliper, its a cube w/ weird notches that allow you to screw the caliper back in to install new rear pads

kaikai114

Got it, I remember someone doing the rear pad install write-up but can't find it anywhere on search, can you direct me to the link? It's my first time doing the brake job, i hope i get everything right...

KC

Mokos23

Time to get an 07 G35 or 06 IS250, obviously Honda/Acura quality has gone down

CGTSX2004

iTrader: (1)

You're trolling again...

xizor

I used my helm's, didn't use the write-up. my tips would be not to forget the shims, put brake quiet on the right side. the rear is very easy IMO