Rear Brakes not locking

[chargerucd]

OK, when i got the 1993 240 it didn't brake well so i got slotted rotors, hawk pads and stainless braided lines. it brakes much better, but when i try to brake hard, only my front brakes lock.

i though it was not bled right, so i bled the brakes again. No solution.

I talked to to a guy that works on a brake place and he said that the pads have some "boss" that has to be alogned with the cylinders, if not the pedal will be spungy.

Is this right?Any other ideas?

(i did a search and no relevant info was found)

Thanks for the help.

[big monkey racing]

you might just have to keep bleeding them cause when I resealed my rear calipers I had to bleed them for a long time before i got all the air out

[DrJuice164]

Ya, your front brakes do 90% of braking so getting the rear to lock would be rather difficult. Being a RWD car, its even more difficult to get the rears to lock as they are attached to the drive line.

Why are you trying to get the rears to lock anyway? (using the floor pedal)

If your trying to use the e-brake to get them to lock, new brakes won't help as the e-brake uses a drum style shoe.

[chargerucd]

Hello Sir,

It seems that either you don't know what your'e talking about as far as 240s or your'e just not talking about the right model car. See image.



Why wouldn't YOU want it to lock?

thanks for the efforts anyway.

Ya, your front brakes do 90% of braking so getting the rear to lock would be rather difficult. Being a RWD car, its even more difficult to get the rears to lock as they are attached to the drive line.

Why are you trying to get the rears to lock anyway? (using the floor pedal)

If your trying to use the e-brake to get them to lock, new brakes won't help as the e-brake uses a drum style shoe.

[DrJuice164]

Hello Sir,

It seems that either you don't know what your'e talking about as far as 240s or your'e just not talking about the right model car. See image.

Why wouldn't YOU want it to lock?

thanks for the efforts anyway.

My mistake, you are correct, I forgot that S brakes were different than Z/R, been a while since I delt with stock 240sx brakes. I have the same question for you, why WOULD you want to lock the rear brakes other than for drifting.... If you lock a tire, its effectly not stopping you anymore, ontop of that, you also flatspot tires. This is no good because once you start to flatspot a tire, the tire will continue to lock at the same spot compounding the problem.
Modified by DrJuice164 at 9:48 AM 6/2/2009

[Cone Junky]

Like mentioned, the front do a majority of the braking (more like 70%) and should lock up first. Besides the fact that most of the load/weight is on the front, they are biased for safety. It is much easier to control understeer (fronts locking) then it is to control oversteer (rears locking) in a corner.

I don't think 240s have a seperate proportioning valve, it's probably in the master, but it might be worth checking out if you really think there is a pressure issue.

If you're trying to lock up with the parking brake, then hydraulics have nothing to do with it. It's a mechanical connection with a cable. They weren't designed to lock up the rears, it's just a parking brake. Check cable adjustment and you may need a longer brake handle for the extra leverage needed to create that kind of force through the cable. I'm sure the drifter guys have the solution for that.

Definitely check the rear brake pads for alignment. Not only will they give a crappy pedal, but they'll constantly drag if that pin isn't lined up with the slot in the piston.

[onosqv]

your car is behaving exactly like it's suppose to - read what Cone Junky & DrJuice (at least the top half of his post, lol) wrote.

the question on everyone's mind: "why do you want the rears to lock first?"

[chargerucd]

No, i didn't say that i wanted them to lock first,

The car doesn't feel like it brakes right, so when i slam hard on the brakes, only the front brakes lock, rears don't seem to work at all (and don't lock like the fronts).

that's what i want to troubleshoot.

Don't your car locks all fours when you slam on the brakes really hard?

[onosqv]

no, not usually. the vast majority of cars, the fronts will lock & the rears will just slow down. You have to do some crazy s*** to get all 4 to lock up in a straight line just braking.

what hawk pads are you running? what brake fluid are you running?

What are you comparing this "doesn't feel right" to? Considering you said it never braked well since you got it, it could be anything... choice pads, fluid, calipers, master cylinder, brake booster, brake bleeder leaking, etc.

having you tried braking in a different 240sx to compare?

If you really think it's something wrong w/ the car & not w/ how you "think" the car should be handling, download the FSM if you don't have it on here (available in one of the stickies or by searching) & walk through the troubleshooting steps.

[driver42484]

Does your ebrake lock the rears? if it does, you need to get a better set of rear pads. I learned this from yrs of auto x. If you want it to really perform you need to spend some money. Metal masters are great for the fronts and ceramic pads have worked well for me on the rear. The metal masters are harder to lock up then other pads.

[chargerucd]

Thanks driver,

thant's great help.

Where do you autocross? I got a miata i am also getting ready to take to autocross in LA.

Does your ebrake lock the rears? if it does, you need to get a better set of rear pads. I learned this from yrs of auto x. If you want it to really perform you need to spend some money. Metal masters are great for the fronts and ceramic pads have worked well for me on the rear. The metal masters are harder to lock up then other pads.

[onosqv]

Does your ebrake lock the rears? if it does, you need to get a better set of rear pads. I learned this from yrs of auto x. If you want it to really perform you need to spend some money. Metal masters are great for the fronts and ceramic pads have worked well for me on the rear. The metal masters are harder to lock up then other pads.

He has hawk pads, they are fine, probably the street one - the reason I was wondering what model/type was if they were the racing ones & he tried to perform these brake tests while the pads were cold, the results would be weird.

In any case, like most of us have pointed out, there probably isn't anything wrong in particular if he did what he said he did correctly. And driver42484 is in PA, so probably autoxing in PA.

chargerucd, come out to the SCCA autox next weekend - June 13/14 - @ AAA speedway, I'll show you my car will lock up front brakes but not rears - exactly how pretty much every car behaves w/ decent tires.