Datsun Roadster Forum-311s.org

Hi friends!
Back home from school for six weeks of winter break so I can finally work on and drive the roadster more (when it's not on fire California has its perks
Engine is pulling strong and with the new (old) Konis and Mike Young comp springs she handles great. BUT...after breaking hard for 2 or 3 corners or even one 80-0 freeway off ramp, the fun is all over! I have all stock brakes and would like to keep it that way but if there are any tips or trick for helping with fade I would love to know. My MC and front pistons may well be original to the car, all lines are stock and I think it's running dot 3 right now. I switched from stock organic pads in the front to semi-metallic after the organic ones basically caught fire following some hard downhill driving (coming down the top of hw9 for those who know). The semi-metallics bite a little better and don't squeak, dust or catch on fire (hardly even smoke) however they still fade very badly. Once, in a moment of shockingly poor judgment, I tried to keep driving after they got really bad (coming down page mill). 3/4 of the way down I was having to give them three pumps before each corner and by the bottom the pedal would go straight to the floor under its own waight like there was an open line or no fluid or something...Thank goodness for parking breaks and first gear! after cooling off for ~ 25 minutes they came back and when I start the car uo in the mornings the pedal is always high and firm.

So really, is this just the reality of stock, non drilled rotors? Or:

would some kind of little air tubing directing cooling to the rotors do the trick?
or dot 5?
or race pads? (I seem to remember Will C was saying good things about some very very expensive performance pads that supposedly did not fade. But did dust, squeak and generally not really work when cold)


Thanks!

my brakes were sucky a few weeks ago and I just needed to blead them all and adjust e brakes . all's good now on stock brakes . did you blead each brake already ? if so , look for a leak or a blead valve not closed tight . if not there , check your lines for brittle cracking , possible original lines like mine were old and not holding pressure .. does it pull to one side when you brake ? if so only some are closing to brake for ya . (like mine were) anyway there's a few causes for soft brakes . time to eliminate.. . . don't forget to down shift . that'll do most of the braking for ya .

Check to see if your front pads are sticking in the calipers. This causes them to not retract enough once off braking, This will allow the brakes to get very, very hot, causing fade, boiling the fluid, pulling, etc. As they get hot they may stick more than under normal conditions. The pads should slide easily into the calipers if you have to tap them in or even force them in you have a problem. I am now running in to this personally Where the passenger side was sticking a little and the driver wasn’t, and now my rotors are worn unevenly, And as I found a when emergency braking, the car will pull to the right.
Worth a check.

No, stick with glycol-based DOT 3/4/5.1 rather than silicone-based DOT 5.

Besides checking front piston retraction, I was going to suggest going to a DOT 4 or DOT 5.1 as they have a higher boiling point. However, one of your Instagram pics (great pics btw) shows you bleeding brakes with Johnsen's Synthetic DOT 3, which claims a 450 degrees F minimum boiling point. That said, the date on that pic is June 2015, so, if you haven't done it since then, you're over a year past flushing the brake fluid. Should do it every two years.

For those wanting to offer more guidance, it appears from Aidan's Instagram pics that his brake maintenance schedule has been:

June 2015: bleed brakes, or was this a complete flush?
Aug 2015: rebuild rear brake cylinders & adjusters, clean up drums
Sept 2016: rebuild front brake calipers
June 2017: replace rear brake wheel cylinders & pads
Aug 2017: replace front brake pads

Let us know how it goes.

Since you mention that three pumps had an effect but eventually the pedal went to the floor, I'm thinking a change to a premium brake pad (EBC, Hawk, etc) and a complete fluid flush/change should help.
I think I recall Will commenting on pads he uses on his race car as working well. A search might yield some better info.
Do you know if the heat from braking is being transferred to the wheel/hub? If your brakes are fading that badly, the wheel should be too hot to touch.
Brake ducting is usually a scoop that's directly in the air flowing at the front of the car thru a large tube to the rotor. It seems like most all the effort to reduce brake fade has centered on the rotor (drilled and slotted, finned, etc) so realistically, if your braking system is working correctly and you're still getting fade, I'm not sure there's much to be done without changing something in the rotor.
Dan

I have some leftover 3" high temp ducting that I am going to use to route air to the brakes, but Im waiting to get a BRE-type front air dam.

The pads Will uses and recommends are called KFP (Part# KFP23-42A) and I think they just doubled in cost to nearly $200 for a front set...

2mAn wrote: ↑Thu Dec 13, 2018 11:49 am The pads Will uses and recommends are called KFP (Part# KFP23-42A) and I think they just doubled in cost to nearly $200 for a front set...

Tried Googling that part number.........nada although I did find a number of posts from various Porsche, BMW, etc. forums stating that finding KPR ordering info was a PITA. Generally referred to third-party resellers. Think KPR has a Facebook page.....ridiculous way to run a business IMO.

KFP Magnum Pads
2463 Columbus Rd NE
Canton, Ohio 44705

(330) 453-9757

I did find a post from Will that said the pads create a lot of dust, which Aidan stated he didn't want.

Again, the basic system should be working correctly first, i.e. complete brake flush and verifying the front pistons & pads are retracting properly BEFORE considering other options like drilled/slotted rotors, race pads, or upgrading.

Many thanks Pete and everyone who chimed in.

I will get the front off the ground and see if they are rubbing.
Here is past discussion of pads
viewtopic.php?t=16942

SLOroadster wrote: ↑Wed Jul 25, 2012 11:13 pm The KFPs blue compounds are the ones you want. They are a carbon kevlar compound however they wear well, and stop VERY well. They dust a fair amount, sometimes they squeal, but they always stop well. Part # is KFP23 then specify either the gold or blue compound. The gold compound is a full track pad, but its fine around town. Ice cold they stop about like crappy stock pads, and warm, holy crap. The cost with shipping is about $110. The direct line to KFP is 330 453 9757.

I've run semi-metalics in the past. BIG mistake. How good were they? Well, after 3 laps at Thunderhill I had 0 brakes till they cooled off. Then I'd get 3 laps again. Still, they didn't last the full 3 laps it was more like 2.25 before braking was seriously compromised and I continued around in a rather unsafe fashion just so I could get something out of the day. In all honesty, I'd guess I drive harder on the street now than I did at the track back then. (Experience goes a long way ) I use a heck of a lot less brake on the track than I used to.

As far as stock roadster stopping power, I'm 99% sure my car will out stop my M3 pretty easily. It requires more leg strength, but it feels better and stops on a dime.

Will

what is fade ?

Mushy and decreasingly effective middle pedal that comes as the result of hot brakes

Replace all three brake hoses.
When you replaced the front pads, did you reinstall the anti rattle shims? These also act as a heat sink between the pad and caliper piston.

If the pedal stays firm, but the car doesn't stop, its your pads. If the pedal goes soft, there is an issue with the brakes themselves.

Yes that is the right KFP part number, but they went from about $100 per set to $200 per set. I'm now looking for a different pad to try. The EBCs might be good for the street, but apparently you need 500 miles of break in before they bed in. Not really a good pad for track use. I've been looking for a p/n for Hawk or Carbotech to try either of those. I'm pretty sure I've heard of Jag E type racers running both, so I'd have to guess there is a part that would fit our cars.

Will

I remember the day that Dave Premo showed me what my Roadster could do in a corner and at speed as we blasted down from one of the hill runs at Shasta. We got to the bottom and there was a set of railroad tracks there so he went to slow down... ah, no... car no stopee! Fade fade fade. While my stock brakes were never good examples of Roadster brakes, that was the day I decided to upgrade my brakes to the vented Maxima rotors and the Toyota 4runner calipers (BTW, NOT a bolt on for those interested). Never faded since (at least the car... ).

That Premo guy.......!!!!

Greg demonstrated his improved brakes when we joined the DatsunsNW run to and around Mount St Helens in 2007.

They definitely stop!

pebbles wrote: ↑Thu Dec 13, 2018 3:26 pm Replace all three brake hoses.

Our wonderful vendors carry regular and stainless hoses. I scored JT's Christmas pricing on set of 3 hoses.