Q45 fronts, now what?
 

I have q45 front brakes installed (twin pistons). Since then i had a bad RR caliper so we replaced it and everything is bled out so there is no air in my lines or system. It seems like the brakes just arent AS strong as they should be. I am wondering if i was supposed to replace the BMC with one that is more directed to the use of the brake upgrade. My brakes work good just not like they should ( i think)

Can you guys suggest a BMC i should be using that I just do not know about.

TIA, i posted this once before and got no response. So just figured i would try again.

UPDATE ON PG 2:

03 altima rear rotors and z31 brackets installed and work perfect. check pg 2

I got q45 calipers ready to go on too. I have heard upgrading to 1" z32 bmc helps with the sponginess. Does it go to the floor now or what?

I have used Q45s on both my cars and have never had any issues. This is on stock BMC which is the perks of the Q45s over Z32s which require a change. Pedal is nice and firm.

What pads and rotors are you using? Are you using your 20yo rubber brake lines because that will make them feel like ass regardless of BMC. Does the braking force fade off or is it just not there at all?

I have Q45s on 3 cars and have NEVER touched my BMC

Never had any issues and 2 of 3 are daily driven. 1 with altima rotors and still no issues

well i do not have sponginess. and my brake force doesn't fade off. It seems like i would have to realllllyy jump on the brakes to lock em up.

I am going to replace the lines with SS ones and try that


I am using::gives:
94 q45 twin piston calipers with matching brakcets
Centric OE pads
stock BMC
rear has new rotors and wagner brake pads.

Did you change rotors? I thought you have to use Altima rotors as a minimum cuz the 240 weren't quite thick enough. That's what my research pointed to.

Well you don't want them to lock up, what size tires are you running and how grippy are they. That will factor into how easy it is to lock it up.

wait are saying it "seems" like it would be hard? or it IS hard to lock em up.
cuz if we are talking hypothetically, your an idiot.

next time it rains or you4 on wet pavement stab your brakes with agood amount of force. they will lock up trust me

to the guy above me. WTF? you use q45 rotors drilled out to 4 lug. or altima rotors with shims. why would you even try to use your 240 rotor? defeats the purpuse of upgrading your brakes.

he obviously thinks he need to be able to lock up his fro94nts for some reason, but its not foinf what he wants on dry pavement. which it dounds like they are operating perfectly.

When I had q45s they locked up on occasion with new tires and my sentra brembos with shitty tires lock up a lot .... For the money q45s are def the way to go

Thats the thing you don't want them to lock up, its the same idea behind getting more grip in corners to go faster. And part of the reason why ABS was created.

Yea nonabs car so....it can be scary at times especially when raining

Since we're on the topic of Q45 fronts, what pads and rotors are you guys using TODAY? I emphasized TODAY because Hawk no longer produces pads for 90-96 Q45 fronts. I also don't want to go with generic Autozone stuff.

Akebono ProACTs AKACT486, decent but not as good as the Hawks(old stock) on my other car. I ordered them from Autopartswarehouse for about 50 bucks. I also got a free 5th pad for a 2005 Camry in the box.

You mentioned you felt the brakes aren't "AS strong as they use to be". This could be a perception thing. You replaced the RR brake caliper. The LR brake caliper May be dragging, ESPECIALLY if its the original. It wouldn't hurt to replace the LR caliper & replace the stock rubber brake line hoses w/ Stainless steel brake lines. I have a S13 w/ remanufactured Q45 front calipers & brackets. Running front Q45 slotted/drilled rotors that I drilled to 4 bolt pattern. I'm also running stock BMC. Like stated above the stock BMC is fine for Q45 caliper/rotor/pad Upgrade. Hope u get it figured out.

First off no i re used the old q45 rotors that came with my conversion.Second off, you may need to re look up the whole q45 front brake install, you will notice info on the rotors you seem to be confused about lol.. :) my s14 (SE original 5lug) has 94 q45 front calipers/rotors/pads/caliper brackets. You use q45 rotors when doing this swap.

I am running g35 oem 19" rays engineering wheels 19x8 f and 19x8.5 R

225/40/19f these are in like new condition
245/40/19R these are balding from me blowing the tires off
yes they will lock up if i made them. but i mean during normal city driving it just feels like it needs a smaller bore master cylinder. (keep in mind i am a newcomer from building hondas for the last 10 years...which on hondas changing the master cylinder to be appropriate to the front and or/rear brake upgrade you install.

i do not "want" to lock up but i felt like it needs more pressure sent to the calipers than it is receiving as of now.

i have replaced the RF and the RR calipers so far because when i received my q45 set up it came with one bad caliper.

SO, with all this summed up.... I have installed rebuilt RF and RR caliper (the rr was leaking!!! wtf? lol) and as it stands right now i got the LF and the LR rebuilt calipers below my computer desk here at work waiting for me to come off the money so i can install them.

I also plan on installing SS all the way around.

i also would like to add, i guess i am just not used to the nissan brakes. I know i keep bringing up hondas but it's what i know best.

On a civic, lets say you remove the 9" front brakes and install 11.1" rotors and bigger single pot calipers, In that case you would remove the 13/16" and put a 1" BMC on to accomodate for the new brakes so the end result is a firmer pedal.

On my s14 my pedal isn't too responsive and its not too firm, it feels right. I honestly think i am just overthinking the situation. :hyper:


i think I should put the left side front and rear caliper on and do some SS lines at the same time and just go from there. :/

IDK about hondas but this is not one so get rid of the smaller bore idea, if anything you would need a bigger BMC bore. EDIT: I see in your post above you are talking about going to a bigger BMC so which is it?

But that is the greatness with this swap you do not need to swap up to a bigger BMC because you are not using brakes with that much more surface area on the pots vs stock. They use two 42.8 mm pistons instead of one 54mm piston to increase clamping force, which yes is about 30mm bigger but its not the huge jump(3x as big as stock) which requires that larger BMC. Two Q45 calipers are about equal to one Z32 in terms of pot size. This swap is tried and true and if you're BMC is in good working order it does not need to be upgraded until you step up to Z32 territory.

Sorry my noobness I have the calipers waiting to go in. Just haven't gotten any rotors yet. And I should have said diameter. But I want to rebuild these calipers before I drop them in. Junkyard rubber tends to degrade fast in az

Yeah new ones usually arent very expansive. I would say $65 a caliper? you can always use those old ones as cores.
I always just bought everything new from a parts store and drilled the rotors out to 4lug myself. Bought a benchtop drill press specifically for it.

You can do the whole swap under $200 brand new, which is totally worth it in my opinion

the q45 brake swap is good. i was amazed by how tiny the little front stock s14 rotors were. Side by side it makes ya laugh lookin' at the little s14 oem rotors, they are so thin and have small diamater.


I found a guy who said he has the z31 caliper brackets so i would be able to do the altima rear rotors upgrade but i need some additional parts such as the z31 brackets.



From what i read it seems like the z32 brakes on the rear are too much BS with the drum style e brake...i would rather do the altima rear rotors w/oem calipers. this is just a street car so q45 fronts and the altima rear rotor upgrade would be ideal for me being i DD to and from work with my s14.

I have the sentra brembos and altima rear and it stops with a very little front biased

sentra brembos? care to share more about this and how it is related to q45 fronts?

im in macon ga btw

i just ordered rear calipers WITH brackets for a 85-86 NA z31. I couldn't find just brackets anywhere, so here at the distribution center i work at i.....

ordered:
crb116251
crb116250

they are 85-86 rear calipers with mounting brackets.

I plan to remove the brackets and just use them with my s14 rear calipers paired with 03 altima rotors.

i received my 85 86 300zx rear calipers/brackets

so i also went ahead and got a pair of 03 altima rear rotors.
Going to grind on the brackets a tad before install, I will update and let everyone know how it goes.

What's better the 300zx or q45 brakes?

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That is a open ended question based on what you want.

You already started a thread about this, and were told to search, then posted in small questions. Pick one spot and stick with it instead of posting the same crap all over the forum. Again search and you will find your answer in a hell of a lot more detail than any of us are willing to post because it has already been covered in detail.

Q45s up front with Hawk HPS pads, stainless braided lines, Z31 rear caliper brackets, Hawk HPS pads, 2003 Altima rotors and braking will be very balanced! This will also make braking more predictable. I stopped locking up the fronts once I had all of these things done.

100octane, do i need to get anything else to do the conversion?

i got:
my 85 z31 brackets
03 altima rotors
new oem pads


anything else i need to get before i start? i am doing it tomorow.


it seems like with my q45 fronts and stock rears my bias is like 88 front 12 rear

Hawk doesn't make pads for 95 q45's any more. I saw someone said they are using Akebono ProACTs. I wonder if q45's with Akebono's are much of an upgrade from stock w/ Hawk hps or hpPlus. With my stock 14's calipers and HP Plus' pads I could stop on a dime but I had to replace them after 3 or 4 months of daily driving, they were noisy as a rusty Amtrak and my rims always looked like shit. Right now I have HPS pads and they are just OK. Waaay better than OEM replacements but I would not take them on a track. Without hawk pads I really wonder if a q45 upgrade is worth the trouble.

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