View Full Version : Changing my front brakes

07-16-2002, 02:59 PM
I checked the FAQ and I didn't see any info on this.
My front brake pads basically don't exist. I need to take the old pads off, replace with new pads, and get the rotors returned.
How do I do this for the front?
Will I have to bleed the brakes and replace with more brake fluid? I am worried about this becasuse I don't want to get air bubbles and have brake troubles.
Thanks, and if anyone answers, could a moderator FAQ this?

07-16-2002, 03:27 PM
If I were you, I would just:

(Get a Helms manual first)
a. Get some new brake pads (I use Hawk HPS)
b. Get some new rotors (Brembo OE)
c. Take off old stuff.
d. Put on new stuff.
e. Bleed the brake system (all 4 corners).
f. Put in new brake fluid (Motul 5.1).

Test drive in a safe neighborhood, break in pads according to instructions.


07-16-2002, 03:55 PM
There is no need to bleed the brake system just to change brake pads.

240 2NR
07-16-2002, 04:58 PM
Correct, you do not NEED to change brake fluid when you change pads, but it's probably a good idea as the fluid is probably crap, old, wet, and dirty (chances are it may even be original to '91). This means that the fluid will now be the weak point in your system. Just getting a sporty pad to operating temp could be very close to the boiling point of the old fluid.

Changing fluid is EASY (it's just a PIA). First get a good Dot 3 or 4 fluid (DOT 5 is not desirable, and I'm not sure DOT 5.1 is worth it, though I don't know enough about it to comment). So far the ones I have used or had recomended were Valvoline Synpower, Castrol GTLMA, and ATE Super Blue (gold same stuff, different color). ATE super blue is in my car now since it gets raced. Really high wet and dry boling points. If you plan to change fluid once and forget about it, you should probably stick to GTLMA (LMA = low moisture activity) or Synpower (avoid all race fluids as they are meant to be changed often and will absorb moisture quickly and will likely have low wet boiling points as well, depsite there high dry boiling point).

Either get some speed bleeders from Don at PDM-racing (if you go to the track or won't have help, get these as they allow you to change fluid quickly and solo $22 for all four corners) or recruit your friend to help you. Get some clear rubber tubing (1/4" IIRC, though I think the OEM and speed bleeder nipple are differing sizes) from Menards or other hardware store (6ft=$1, its cheap).

Then bleed brakes in this order for non ABS:
DR -> PR -> DF -> PF

To bleed brakes loosen bleeder screw (or replace with speed bleeder) and place enough hose over the nipple to run down to a catch can. About a half turn should open the valve and when you depress the brake pedal it should go to the floor and pump out fluid. If using speed bleeders continue to pump evenly until done and retighten, otherwise when the pedal is at or near the bottom of it's travel you must manually tighten the bleeder, then release the brake, open the bleeder, pump, tighen, release, repeat.

Things to note:
-Keep an eye on the resevoir level. Refill at the low mark. If it gets too low and draws in air you must start again.
-The hose has two purposes, the first (1) is to keep an eye on the fluid so you can see when the color changes from brown to the color of the new fluid (usually clear) and so you can see if any air bubbles are coming out (the fitment of the hose must be snug on the nipple so air is only coming from the bleeder and not outside). The other (2) purpose is to keep the fluid from dripping down on the caliper.
-Avoid spilling brake fluid as it is very abrasive and will destroy paint (and makes your fingers feel funny).
-Brake Kleen (I recomend the green can) is a good way to clean up the brakes when done.

07-16-2002, 05:47 PM
Good brake bleeding bit. Why that order? I always do it my chanels (RR & LF; LR & RF - furthest from master channel, then the closer one.

As for the brake job itself - easy as pie:

1) break lose lugs
2) jack up car (whole front if possible or do it one side at a time)
3) remove wheel
4) take a 12 mm wrench to the bolts on the back side of the caliper (NOT 17 mm) and losen
5) pull top of caliper up and off (it may be a little stuck depending)
6) pull old pads out of caliper top and hang top on the spring (you don't want to let it dangle by the brake lines)
7) take a 17 mm socket and losen the two bolts on the caliper assemply that is still on the disc and remove it and set it aside
8) take a small screw (find one that fits) and turn it into the holes on the brake rotor (inside where the studs are) - tighten it until the rotor comes lose (it will likely be rusted to the hub)
9) take rotors to local shop to be turned or trash them and clean them AND the caliper area before re-fitting
10) put rotors back over studs and in place (they just sorta rest there for now)
11) reattach caliper assembly w/ 17mm bolts - DON'T GROVE YOUR NEW ROTOR!
12) open brake fluid resevoir
13) take a 4" "C" clamp or specialty tool and compress the pistdon in the caliper that is hanging on the spring EVENLY!!!!
14) put new pads into little spring clip assembly dealies w/ the squeeler shims and all that
15) slide caliper assembly back over new pads/rotor (if it's too tight, compress piston more)
16) line up and reattach caliper w/ 12mm bolts
17) DOUBLE CHECK - IS IT ALL TIGHT?  If you need to, bleed the brakes now or just put the cap back on the resevoir
18) put wheel back on - remember 80 lbs/ft!!
DONE - now go clean your nasty a$$ hands <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'>

07-16-2002, 06:49 PM
Thanks guys. I'll give it a try when I get my rotors returned and my pads come in &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

240 2NR
07-17-2002, 09:07 AM
Hippo- The order for the brake bleeding is per the FSM. &nbsp;I think it's not how far they are from the MC physically, but also has to do with the routing of the lines. &nbsp;I was kind of surprised too, as I did it a different way the first time and the way I posted the second time. &nbsp;I'll double check that it's right this week, but I'm 90% sure that's right (bled my brakes and my GF's altima within the last month). &nbsp;The order does change for ABS cars, but since I don't have ABS, I don't remember (probably since I never read it other than to see it was different). &nbsp;I can post it as well though when I check.

I do think that the order is intended to get the best fluid up front as if you do not introduce air into the system it shouldn't matter the order. &nbsp;By doing the rears first you flush the greatest amount of fluid and begin replacing it so less old fluid is mixed in with the new fluid in the resevoir.

07-17-2002, 01:05 PM
2NR - inte(rolling the "R" like Charro)estink.

I agree when flushing to get the backs done first to reduce fluid waste, but on a normal bleed, I always did it cross ways. &nbsp;I never checked, but I always assumed that Nissan, like most other cars used a two channel brake system (i.e., connected front and rear from opposite sides) so that in the event you had a catastrophic failure on one corner, the car could still stop. &nbsp;(I know Honda's do) &nbsp;But that's why I crossed. &nbsp;Does the FSM mention anthing about two channels?

In any case, I agree that it doesn't matter if you don't let in air. &nbsp;I'm just anal like that <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'>

240 2NR
07-18-2002, 07:42 AM
Ok, checked the FSM and the way I indicated was correct for the 93 240sx (not sure if there were any changes to the systems in S14). &nbsp;As for diagonal 2 channel systems, isn't the 240 fully independent? &nbsp;I'm pretty sure that at least the fronts are (trying to draw a picture in my head of the master clylinder and I can't recall if three or four lines come off). &nbsp;In anycase, usually when late model cars have diagonally paired brakes, it was in early ABS systems, and I know the 240 uses a diagonally paired 2 channel system for that, and is also the reason many racers turn it off. &nbsp;

The order for ABS cars is the same:
DR ->PR ->DF ->PF
and then the front side of the ABS actuator, followed by the rear (obviously that part is not the same for non ABS cars).

07-18-2002, 11:51 AM
Thanks for the info. &nbsp;That makes he job easier anyway!

07-18-2002, 01:36 PM
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