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View Full Version : N15 sss brake pedal firm



mad082
22-05-2017, 12:12 PM
Hi all,

Just wondering how firm other people's brake pedal is. The pedal in the missus n15 sss is somewhat firm and it doesn't stop that great. The pedal goes down the first part reasonably easy but after that it gets hard quick.

I've done the simple tests on the booster to check it is getting a vacuum and then holding (pumping the pedal with the engine off till it goes firm then starting the car while pushing on the pedal and it does drop like it should) and the check valve is working. I haven't tested to see what vacuum the engine is running yet in case it's simply a case of it having a leak that is making it not reach enough vacuum to properly assist in breaking, and I'm going to flush the system to make sure there isn't a blockage somewhere, but none of the brakes seem cooler or hotter than the others (although it takes a few hard stops from 80kmh to get the rears to be anything more than just warm). The fluid is the original fluid (which is why I'm going to flush it) and the front pads were changed a few years back. Rears are still the originals and have a decent amount left.

To best give an idea of how firm the pedal is, it's pretty much the same as when you pump the brakes when the engine is off, but it has the free play at the top of the stroke like it should. Other cars I drive you can always push the pedal further and even once it firms up you can usually get a bit more out of it.

The initial bite is pretty ordinary and low speed stopping is sometimes really bad unless you push reasonably hard. If I push pretty hard I can get the fonts to lock up but it's a fair bit harder than other cars.

I don't drive the car that often so I don't really know how long it's been doing it. The missus doesn't really notice it since that's all she drives and doesn't drive it very often or far.

Just really wanting to know how it compares to others and any ideas on what else to try that won't cost much in case it's not the cause.

sss4me
22-05-2017, 01:49 PM
flush the system completely out,starting with the furthest line from the master cylinder, it will be a good start

would not say the n15sss brake pedal is particularly firm at all (least mines not), but after a bit of travel the pedal should slow down quick enough. might i suggest next time you upgrade, get some slotted dba's and some performance pads (projectmu,qfm,ferodo) will make very short work of braking (pun intended).

007adr
23-05-2017, 05:25 AM
I think it's booster problem


Sent from my iPhone using Tapatalk

mad082
25-05-2017, 07:43 AM
Yeah I'm starting to think that too. I'll try and flush the system this weekend just you be sure but I think I'll try and get a hold of another booster to try. Anyone know if the 1.6L models use the same booster as the 2L? I know the rest of the brakes are different

PhilSSStevenson
28-05-2017, 12:23 PM
Yeah I'm starting to think that too. I'll try and flush the system this weekend just you be sure but I think I'll try and get a hold of another booster to try. Anyone know if the 1.6L models use the same booster as the 2L? I know the rest of the brakes are different

The booster is the same for 1.6 and 2.0

Cheers

Cozzm0
28-05-2017, 04:26 PM
Booster part numbers are different for the N15. Don't know what is different, but they're not listed as interchangeable parts.