The New Soft Brake Pedal Thread.

[Duncan]

yeah that's right battery, thats a ghetto solution to stop the brake lines expanding, I'm going to guess it would work pretty well.

As for braided vs rubber lines:

Brand new you would never pick the difference between them (rubber or braided will feel identical)

Many braided lines are not street legal, certainly the cheaper ones are not. They need a plastic cover over the braid to protect them from rubbing through.

Since most people replace old rubber lines with braided ones they feel the difference. But new rubber ones would be just as good for the next 10 years, cheaper, and legal

[Pezhead]

Hey fellas, I'm interested in your opinion here.

I recently took my car to the track and now have the spongy feeling brakes. The car ran OK throughout the day, but I probably ran it too hard during the sessions at the end of the day. At the end of the day, it felt OK but could feel the brakes weren't biting like they should.

I did change the pads 4 months back to EBC Reds and changed/bled the fluid with Motul 660 the weekend before the track day.

I drove home and was a little mushy so I thought it was just glazed pads or some boiled fluid. The pads were glazed so I scuffed the glazing off but the softness was still there.

So I rebuilt the master cylinder this weekend. I've got more pedal now, but still can't lock-up/get the ABS to kick in. This is on an R33 GTR.

Since the brakes were ok before the track day, I think it might be heat related. There's plenty of brake pad left - but could I have ruined them by overheating them? The rotor's don't look bad - no visible signs of overheating. ABS Unit?

I'm a bit stumped. When I have time, I'm going to try putting the old pads back in to see if that makes a difference.

[Country Cruzin]

Got air in my brakes lines from the resoivar spent hours an hours bleeding them had a mechanic bleed them but cant seem to get all the air out pedal is very soft to start with but will still lock the wheels up easily at 100km/h when you push the pedal in further. Does Anyone Know HOW to Bleed the ABS. its on an R33 GTR. any help would be great.

[Wacky Dee]

Interesting topic .. just had new rotors (RDA slotted) and new pads (QFM HP-X) installed on my GT-T and I still have the soft pedal feel up top (2cm movement) before any sort of grab ..

Gives me zero confidence in the brakes Also my brake pedal slowly sinks by about .5cm every 10 seconds or so when you hold your foot on it which is not a major concern as I don't need to hold my foot on the brakes for a long time as most my trips are around town.

Anyway, gonna try rebuilding the calipers .. see if that fixes the useless soft feel at the top. It shits me when a 10yo corolla has much better brakes than a street skyline of the same age, especially after spending $800 on new rotors and pads.

[nuffsaid]

I dont think its a pad or rotor issue that causes the soft pedal

Bleed your brakes properly

Maybe rebuild calipers

Check brake hoses

Check your brake master cylinder

Not sure what else there is to do?

[bnr#@]

Interesting topic .. just had new rotors (RDA slotted) and new pads (QFM HP-X) installed on my GT-T and I still have the soft pedal feel up top (2cm movement) before any sort of grab ..

Gives me zero confidence in the brakes Also my brake pedal slowly sinks by about .5cm every 10 seconds or so when you hold your foot on it which is not a major concern as I don't need to hold my foot on the brakes for a long time as most my trips are around town.

Anyway, gonna try rebuilding the calipers .. see if that fixes the useless soft feel at the top. It shits me when a 10yo corolla has much better brakes than a street skyline of the same age, especially after spending $800 on new rotors and pads.

If youre holding your foot on the brake pedal and its sinking slowly then your master cylinder is stuffed

[Jmaac]

If air becomes trapped before the abs modulator then it can be really hard to push out. Im not sure with the skyline if theres special bleed screws on the modulator for this purpose as I dont have it on my car. If there isnt you will need a special device to cycle through the abs solenoids whilst you bleed the system

[Wacky Dee]

If youre holding your foot on the brake pedal and its sinking slowly then your master cylinder is stuffed

Yeah that's what my mechanic said too but to me that slow sinking is not a major concern as I don't go down long hills too often where I need to hold the brakes for so long...

However, would a stuffed master cylinder also cause the soft feel up top? Reason I'm asking is, I don't want to spend $500+ on the master cylinder if it's only gonna fix that slow sinking issue. I've read in previous posts that people replaced their master and still had the soft pedal feel...

So I'd much rather get the calipers and pistons reconditioned if they are more likely to give me what I'm after ie. better pedal feel up top and none of the spongy crap.

[Wacky Dee]

If air becomes trapped before the abs modulator then it can be really hard to push out. Im not sure with the skyline if theres special bleed screws on the modulator for this purpose as I dont have it on my car. If there isnt you will need a special device to cycle through the abs solenoids whilst you bleed the system

I'll ask my mechanic about the abs modulator ... can trapped air in the abs cause this sort of soft pedal feel? I get a feeling this is a common issue on skylines and there's still no definitive answer as to best way of going about fixing it (best = not spending unnecessary dough like master if not needed)

[Jmaac]

The master&slave cylinders are just housings that contain a piston that moves hydralic fluid. If they were to go bad im sure they would be leaking fluid allover the place under these pressures (in theory its posssible that it can be sucking in air under negative pressure/vaccum. This means the unit would be extremely close to failing and/or just a crap design). Alternatively the inernal spring may not be giving you full return. Im sure you can get master cylinder and slave cylinder reconditioning kits much cheaper than buying the overall unit if you feel its an issue ($14 for slave reco kit for VLT box few years ago, $50 for master i think but totally different design). You can even improve your breaking force force by machining the housings out and make a larger pistons to suit if you wish (use F/A = F/A as a guide). Do skylines have vaccum assist? im not totally sure as I havent really worked on that side of the engine bay yet but leaks there wouldnt help either.

Any air can definately make it feel spongy (air is compressible whereas (most) fluids are incompressible). Some manuals for other nissan makes state, "turn ignition switch "OFF" and disconnect ABS actuator connectors or battery ground cable" before bleeding.

Hope that helps

[Jmaac]

whoa got a little sidetracked whilst responding to a clutch email (same theory). by slaves i mean the pistons in the calipers. I think it was only a little more for a caliper reconditioning kit (2 pot), not sure why i threw out a clutch slave cylinder price but you get an idea on the cost of a few seals, springs etc.

[pipster11]

just having the same thing on my r32 gts-t spec m (with abs)

very little bite for the top 1 or 2 cm then they are rock solid

as for bleeding the abs the guy who did them for me just said that you bleed the abs first (mine has bleed points on the top of the unit but i think it may need re bleeding from the unit again)

can anyone verify that the abs units from r32 gts-t's are the same or compatible with gtr's please?

would like to get the bottom of this as i've just swapped the abs (leaking like a mofo) for that out of a gtr

lined up and plugged in like a beauty but there is 1 number different in the part number but i had spongy pedal before and after the abs swap (and full bleed including front rotor swap)

Edited April 25, 2009 by pipster11

[bnr#@]

just having the same thing on my r32 gts-t spec m (with abs)

very little bite for the top 1 or 2 cm then they are rock solid

as for bleeding the abs the guy who did them for me just said that you bleed the abs first (mine has bleed points on the top of the unit but i think it may need re bleeding from the unit again)

can anyone verify that the abs units from r32 gts-t's are the same or compatible with gtr's please?

would like to get the bottom of this as i've just swapped the abs (leaking like a mofo) for that out of a gtr

lined up and plugged in like a beauty but there is 1 number different in the part number but i had spongy pedal before and after the abs swap (and full bleed including front rotor swap)

Interesting that as the r32 GTR service manual says to bleed the ABS AFTER bleeding the brakes in the usual order..

[bnr#@]

Yeah that's what my mechanic said too but to me that slow sinking is not a major concern as I don't go down long hills too often where I need to hold the brakes for so long...

However, would a stuffed master cylinder also cause the soft feel up top? Reason I'm asking is, I don't want to spend $500+ on the master cylinder if it's only gonna fix that slow sinking issue. I've read in previous posts that people replaced their master and still had the soft pedal feel...

So I'd much rather get the calipers and pistons reconditioned if they are more likely to give me what I'm after ie. better pedal feel up top and none of the spongy crap.

I wouldnt be taking my chances with the master cylinder... Yes it can be the cause of your problem to...

Shouldn't cost that much to fix, just get a brake guy to put a sleeve kit through it...

[pipster11]

Interesting that as the r32 GTR service manual says to bleed the ABS AFTER bleeding the brakes in the usual order..

fingers crossed that that gets rid of it then

will give it a go when i get some time and report back

[Birth]

I'd be real interested to see how much it costs to have the master cylinder resleaved; pipster11, look forward to your reporting back when you have looked into it!

[nfi]

I have found that skyline, 200sx's with ABS always have a mushy pedal. I have never driven one that doesn't. I reckon I would have driven probably 10 skylines and maybe 15 s15's. The skylines without ABS always have firm pedals.

GTR's this is never an issue though they don't seem to have a problem...

I have a hypothesis though.....

Given the skylines without ABS have firm pedals and the rest of the skylines and all s15 (given they all have ABS) have a mushy pedal (even with braided lines, track pads, RBF600) I think it has more to do with the master cylinder.

When a person upgrades their calipers to brembo's or something bigger on a gtst or a s15 they always complain of a spongy pedal. Once the master cylinder is upgraded it fixes the problem.

What i think is happening on gtst's and s15's is once you add ABS the master cylinder is just not big enough to cope with the additional capacity/load (even though its hydraulic and therefore shouldn't matter) of the ABS system so it hence spongy.

Having driven an s15 with brembo's and a 350z master cylinder, even with the ABS the pedal was nice and firm throughout its travel.

[skylinecouple]

Can anybody confirm the 350Z master fitting a Skyline ? Yes I know James said it was an S15 but perhaps it may fit a R33 Skyline ? I can get my hands on one and would agree with James that the ABS cars all seem a little soft.

[dorifticon]

Hey

I have an abs-equipped r32 GTR. I had terrible brakes upon import. I had the stock MC resleeved, it cost about $250 (including removal and reinstallation). I also had the booster rebuilt.

It improved it but was still abysmal. Next step was to machine stock drilled rotors, and replace pads with Bendix ultimates (and of course bleeding all calipers and ABS unit as per manual). Again, improved but still rubbish.

Then I had the brakes pressure bled by a brake place (as opopsed to the home method of one person working pedal, another lockign and unlocking the bleed nipple). It helped the initial mushiness to the point where I am confident driving it around but would still like to improve it - I may look into the MC brace.

[pipster11]

how much did the pressure bleed cost you?

sounds also that you could use new brake lines if the initial mooshie ness is better now and the rest it a bit crap