post Q45 Brake swap problems

[OptionZero]

I just completed swapping the Q45 brakes , and have a gigantic problem.

When I step on the pedal, there is ZERO resistance, no braking force until the pedal hits the bottom.


All 4 corners were bled (the fronts with Russel Speed Bleeders), fluid leve is topped off and checked before and after bleeding.

THere is no brake fluid leakage we can tell, as fluild level is the same after we tried some braking runs.

After the swap, i also got a LOUD creaking/groaning noise from the rear half of the car, possibly the suspension...we do not suspect the brakes because we did not touch them at all.


The swap:

Q45 rebuild calipers with stock brackets. For those of you who want to do the swap in the future, USE THE 240SX BOLTS to Bolt the caliper to the car, the q45's are WAY too long

brembo rotors, blank

earls' stainless steel lines

axxis metal master pads

Possible problems:
We may have gotten brake fluid on the rotor, which would result in lots of slippage and explain the lack of braking force. This does not explain the lack of pedal pressure or the croakin noise.

Leak? No fluid was found on the ground of the parking lot where we tested the car...we tighted everyhing, we have every washer in place...

Master cylinder: we didn't touch this at all, because the main advantages of the q45 swap are using stock lines and MC...i dont see how we could have damaged it.

Actually, while putting the new lines on, i may have pulled on the line a little bit, which MIGHT have applied force to the MC? I will check on this in the morning, it is far too dark.

Finally, I changed my Zilvia.net sticker from a blue one to a new white one. Clearly, West sent me a defective one which destroyed my brakes. Damn you!


Any other suggestions? Tomorrow I will shoot the brakes with brake cleaner and wipe off any lubricanting brake fluid...and look at it in the day light, since we did this at nighit (bad idea)

To anyone doing the swap:
make sure you have bracket AND caliper, they are separate parts on the Q45

Use 240sx bolts (hey are shorter than q45 bolts) when bolting rotor to caliper

Keep ALL the washers, know where they are.
Speed bleeders kick ass

Have a friend who knows something about brakes.

When taking off the big bolts (2) holding calipier to car, remember that lefty is not loosey because they are facing a different direction

GET A FUCKING LASER SCALPEL TO CUT THE HEATSHIELD. I swear that thing is the devil incarnated into a thin sheet of metal....its impossible to bend properly, just bite the bullet, shell out $30 for a GOOD SET OF CUTTERS and cut that shit off.

[OptionZero]

seriously need help guys...

took a second shot at it today, totally bled all 4 corners in order, ebrake down. Found one faulty speed bleeder, got the air outta that side of the car, bled it again, replaceed it with a regular bleeder....

STill nada, no brake pressure till the pedal hits the ground...

Its almost as if air is leaking out or something of the vacuum, i cannot stop the car without pressing it all the way down, thats alot of slippage.

[chineseb0i]

yea..we worked on it today and found there was a big air bubble on the driver side so when we were bleeding it, it was emptiness for quite some time. Before that happened actually, the speed bleeder seemed to have gotten caught so basically shit got trapped in there. I'm guessing it would be master cylinder failure. However, the brakes stiffen when pumping when the car is off but once the car is on, there is no brake at all and sinks to the floor. Any diagnoses? Perhaps the mc is going out, the seals going on, thus causing these debris to go through the lines and clog them up? Possible brake booster? There is no power going to the brakes so what should we check for?

[AutoRnD]

try removing the speed bleeders and going back to stock bleeders...

[INeedNewTires]

check for vacuum leaks as well. especially to the brake booster and sometimes that check valve thats inline from intake manifold to brake booster fails, if your pedal becomes immediately stiff after you turn off the car then that is the problem. good luck man, me and my friend did a brake job with speed bleeders and it worked without a hitch, maby they arent tightened down enough?

[240Stilo]

Take off the speed bleeders. Bleed again. If you still have problems do a search on how to bleed brake system in case you're doing it wrong.

[OptionZero]

found the problem: we switched the calipers...right was on left, left was on right...ugh...stupid mistake, took a shop to see it and rectify it.

Brakes actually work now! I was expecting a bit more bite, though, but they are better than stock

[chineseb0i]

yea, installed backwards. Confusing as fuk though cuz on the stock 240's the piston is in the inside so i thought the q45's would be the same but they are not. Since they are switched, the 2 piston system is on the outside of the rotor rather than inside..shoulda checked but glad things worked out

[andrave]

what wheels are you using? I want to do this swap but I'm not sure if my 15x6.5/7's would still fit...

[Zemus]

Originally Posted by andrave

what wheels are you using? I want to do this swap but I'm not sure if my 15x6.5/7's would still fit...

Q Brakes clear stock steelies

[CustomS14A]

what year Q45 brakes are you using

[S13Grl]

I was gonna sugest bleeding the master cylinder and the ABS actuator if you have ABS.

P.S. I'm so glad it's not our sticker

[OptionZero]

Any year from '90-'96 will work for sure, the newer Q45's i dont know, and for the price/difficulty of finding post '96 ones, you'd be better off getting 300ZX calipers.

These will fit on S14 SE rims, with about a half inch to clear. Again, brakes have to do with spoke design, NOT offset...you probably need a 16inch rim (quite sure of this).

Having driven on it for a few days, I can tell you that after 30mph, brakes are NOTICEABLY stronger, but under 30mph the difference is pretty marginal. THis is probably good as you dont want super giant braking force when you just tap the pedal at low speed anyways.

I may try the brake booster adjustment in the Zilvia FAQs to get a little more braking force when you first step on the pedal. It is a quick adjustent found in the Full Service Manual as well, and requires only a coupla wrenches and removing 2 bolts (takin off the master cylinder from the brake booster to reveal a piston).

I'll try it when I get back to Davis with chineseboi mebbe.