Firm pedal, less stopping power.

[Laecaon]

So I was driving my car last night. Drove it an hour on the freeway to my destination, and all was well. Then drove back home an hour on the freeway, not using the brakes once. As soon as I get to the off ramp, I start braking. I suddenly notice that Im not stopping at my usual rate, but what made me clue in, was that I was well into the pedal being rather firm area, and usually my brakes are fairly touchy. I had to apply a bit more pressure than usual as the pedal felt firmer (but I think thats because I was pushing the pedal further), to achieve adequate braking.

 

Now lets say I usually stop with my pedal 1/4 distance to the floor. I had to have it at 1/2 distance to the floor. Its around this point that the fronts really start grabbing and will soon decide to lock up.

 

I would also say, my pedal feels the same in regards to stiffness.

 

I realized that I had just driven in decent rain a couple puddles on the freeway...

 

On my street as I came home I did some brake tests. I can still get my fronts to lock up, but it just does not feel right anymore.

 

I have brand new Pads and Rotors on the front (280zx) as of 2 months ago or so. No booster. Rear brakes were adjusted in August.

 

Did my rear drums get saturated?

 

 

My only experience with this type of thing is from my disc brake mountain bike. Sometimes after awhile of going through some serious dirt and grime, I have to take the pads off and degrease them (with like simple green) and then hit it with rubbing alcohol. It would suffer similar brake feel. Say the lever pull percent to braking percent was very linear normally, but when dirtier, It had a lot less performance at low lever pull, but then would suddenly creep back up to full power, more exponentially.

[DRIVEN]

Sounds like the rear circuit is bypassing inside the master cylinder. Fluid level still okay?

[datzenmike]

Water will do this, yes. But in my experience there is braking loss with the same effort only if severely submerged. The close rubbing disc pads rub it away in a few hundred feet or less, one of the reasons for residual valves in the master is to hold the pads against the rotors to keep them clean.

 

Brake fluid contamination will do this but unlikely both fronts and the backs at the same time. Oil spray contamination maybe? Any chance you drove through something on the highway?

 

Spray down both sides of the rotors with carb or brake cleaner to wash off any contamination. Maybe pull the rear drums off too, though unlikely anything would get in there.

[Laecaon]

I should go check the fluid level...

 

I actually have in mind to do a brake fluid flush very soon.

 

 

 

And I just checked. Fluid level is not okay in my book. Rear cup is low, and front cup is very low. Der.

 

I should have done my fluid flush when it was drier...

[DRIVEN]

Got a vacuum bleeder?

[DISLEXICDIME]

adjust the rears

[Laecaon]

Nope, never needed one. I just keep pouring new fluid into the MC and connect a clear tube to one of the nipples (which ever one I am bleeding/flushing at the moment) and keep pumping away until I see a color change in the clear tube.

 

Its how I have always bleed brakes... worked the Datto, 01 Jetta, 99 Caravan, and my moms 09 Journey.

[Laecaon]

adjust the rears

 

Seems a bit premature, parking brake still grabs easy.

[Dawa]

whether its the problem or not,

if your brake fluid is a few years old, swap it out for some dot 4.

super inexpensive.

[Laecaon]

whether its the problem or not,

if your brake fluid is a few years old, swap it out for some dot 4.

super inexpensive.

 

Good thing I have like 2 quarts of Dot 4 laying around...

[Laecaon]

Drove the car a little more.

 

It definitely feels like the rear brakes are not acting normal.

 

 

I have driven enough cars to say, What brakes I do have are way safer than a lot on the road. Many would get into my car and even wonder what I am griping about.

 

But now my quest begins, begone black brake fluid.

[ggzilla]

Firm pedal means it works good without having to press it very.far. Firm (stiff) pedal is what you want.

 

Hard pedal means you have to press extra hard to get the vehicle to stop. Hard + extra travel will happen if the brake booster stops working. Or if the brakes are contaminated. Another cause is rear brake portion of master is no longer working.

[Laecaon]

Hard pedal means you have to press extra hard to get the vehicle to stop. Hard + extra travel will happen if the brake booster stops working.

 

Good thing I dont have a booster!

[ggzilla]

Hows is that good.or bad? Your brakes arent working as normal, which is not a good thing.

[Laecaon]

Hows is that good.or bad? Your brakes arent working as normal, which is not a good thing.

 

I can eliminate it as an issue...

 

 

[bonvo]

sounds like the issue i had my brake pedal would go down further before grabbing for me it was the old rotors and worn brake pads taking up all the travel in the pedal but since yours are all new i seriously recommend adjusting the rears the e brake is mechanicly operated and you may be moving the shoes more with the lever then the wheel cylinders can push them out

[Laecaon]

I will be addressing everything tomorrow.

 

Today I started to hear a cool sound... when braking there was a "grinding" or "metal sliding on metal" sound from the rear.

 

Honestly I have never been able to get the rear drums off (I have on my friends 521 and my sisters van) but my 4lb hammer isnt doing it.

 

I have a feeling I need new shoes, and possibly new drums.

[ggzilla]

Forget the hammer, Datsuns have threaded holes so it can leveraged off by screwing in two bolts. But first back way off on the adjusters.

[Laecaon]

Yes my 510 Has the holes. my friends 521 did not.

[DRIVEN]

You need some sexy aluminum Z drums anyway. All the cool kids have em.

[DISLEXICDIME]

hmm i wonder if a shoe has come un glued