kyle Posted July 30, 2007 Share Posted July 30, 2007 Hello all- I have a warmed-over 72 240Z with stock brakes; it has SS lines, ATE blue/200, Hawk HP+ (40% thickness or so) and FSBC's on the front, OEM rear shoes at probably 30% (WAG, they're about 1/8" thick). No leaks, the master is about ten years old, front calipers have been rebuilt, and I believe the rear cylinders were new OEM five years ago. After a system bleed and adjustment of the rears, the brakes were fine around town and on the highway, with some serious abuse (trying to find any trouble before track day, don'tcha know). Out on the track Saturday, they were awesome for the first half of the session. Then the pedal got a little lower and braking wasn't as strong. The pedal was still firm though. As the session wore on, I wound up having to pump it once before each serious braking event. For the second session, I was ready to shelve the car in favor of my stock Miata for the day, but remembered JohnC telling me to adjust the rears every session.... so I did so (15 clicks), and went back out. Voila! perfect braking again. For half the session. Back to a pump-up, which wasn't a big deal at all - used to it by now. So, for the third session, I adjusted the rears again (about 10 clicks), and no change. Again, not a big deal, and once pumped up, the brakes worked fine. Any ideas? My guess was that the brakes probably needed a bleed after the first session as well. I haven't tried bleeding anything yet. Would that be normal, to have to bleed and adjust every session? Any way to get closer to maintenance-free brakes for a five-session day? Oh, and any suggestions for a slightly more aggressive pad that retain some semblance of streetability? The car is really only driven to, from, and on the track. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 30, 2007 Share Posted July 30, 2007 Would that be normal, to have to bleed and adjust every session? Any way to get closer to maintenance-free brakes for a five-session day? Oh, and any suggestions for a slightly more aggressive pad that retain some semblance of streetability? The car is really only driven to, from, and on the track. Yes, that is normal maintenance for the track. It sounds to me like you were maybe starting to boil the fluid too. You might consider some venting to the front brakes. I've tried Porterfield R4 pads on the street and in my opinion it isn't a good idea. I had a not panic, but harder than usual stop with them once after a good long stretch of freeway and there wasn't much there. Turned into a panic stop by the end... Get closer to maintenance free? That's easy. Get some big ol 12 or 13 inch Wilwoods or PBRs or whatever suits your budget and slap them on. You won't have anywhere near the maintenance issues that you do now. Quote Link to comment Share on other sites More sharing options...
kyle Posted July 30, 2007 Author Share Posted July 30, 2007 Thanks, Jon - I have ducting from the spook, forgot to mention that. Yeah, bigger brakes would be nice, but then that means new wheels, and hell, I may as well get a set of those slick ZG flares too. Then I'll definitely need more power, so let's get that turbo happenin. Then we're talkin scary fast, so I better put a cage in. And, of course, before all that, I need to get off my ass and put some camber plates and coilovers in. Sigh, where to stop... Would different fluid perhaps help? I like the ATE stuff for the dual color and the relative affordability versus Castrol SRF and the like. On the plus side, the fact that I'm using the brakes up suggests I'm getting quicker. That's always good for the ole ego. Quote Link to comment Share on other sites More sharing options...
bjhines Posted July 30, 2007 Share Posted July 30, 2007 I tried the stock brakes and various combinations until I ended up with vented toyota fronts and the MM 240SX kit in the rear. One of the things I found was that the rear drums do not have much bite under hard braking unless you are using a race friction material on the shoes. Custom lined rear shoes and the cost of the drums makes the rear drum brakes INCREDIBLY expensive to maintain, and they will always have lackluster performance. The fronts can be improved.. but they will always be overworked until you actually get some bite in the rear shoes. I was cracking rotors with dual ducted and vented Toyota disks in front until the day I actually got a decent set of rear brakes. Quote Link to comment Share on other sites More sharing options...
kyle Posted July 30, 2007 Author Share Posted July 30, 2007 ...innnnteresting. I stupidly have been thinking of the rear brakes as more or less just along for the ride. Mayhap I need to get on the rear disk bandwagon. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 30, 2007 Share Posted July 30, 2007 Doesn't Porterfield do shoes for the Z? Some R4 shoes might help, and that I think I would risk on the street. Quote Link to comment Share on other sites More sharing options...
bjhines Posted July 31, 2007 Share Posted July 31, 2007 Hehe... If you want an idea of how much the rear brakes do then cap off the rear brake spigot on the MC on any car. Drive that around your neighborhood when there is no one to run over. Assuming you have race shoe linings: The thing about the drums is the way they change shape when hot. As you have already found they will need adjustment frequently. The other problem is that the drums warp into a tapered shape when hot. They will chamfer the shoes under hard braking and then they have poor contact with the drum until super hot(or the shoe are worn flat) again. The braking will be fine for a few(3-6) sessions and then they won't adjust anymore in the pits. That is the point when the shoes begin to noticably taper. From that point on the braking will be inconsistent, depending on drum temps. On a side note: The drums actually cool down fast. I was sandblasting them clean to ensure proper cooling. It turns out that they can get to a point where the rear drums cool off too much between braking zones. Then you have a little extra pedal stroke before the shoes properly conform to the cool brake drums. The pedal will feel then feel hard if there is another braking zone in quick succession. Quote Link to comment Share on other sites More sharing options...
kyle Posted July 31, 2007 Author Share Posted July 31, 2007 argh, how this pains me after 15 years of smugly thinking that guys swapping rear discs on are posers. Guess that shelves MS and turbo for another year... brakes and cage this year. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 31, 2007 Share Posted July 31, 2007 One intermediate step might be to try some 510 drums. They're cast iron and although I always thought the aluminum drums were the hot ticket and all my 510 friends run Z drums, occasionally you'll see someone saying that the cast iron drums don't distort as much. Quote Link to comment Share on other sites More sharing options...
jt1 Posted July 31, 2007 Share Posted July 31, 2007 When I bought my car, it still had the drums on the rear, and I had the same symptoms you did. I would start a track day with good brakes, and have no rear brakes by the end of the day, despite adjusting them between runs. I upgraded to rear discs, and they are consistent thru the day now. You will most likely need an adjustable proportioning valve. jt Quote Link to comment Share on other sites More sharing options...
kyle Posted July 31, 2007 Author Share Posted July 31, 2007 Okie dokie, I'm sold. I happen to have a proportioning valve in my parts bin that I've never used... hope my Z won't mind parts emblazoned with "Mopar Performance". I see Ross has caliper adapters for $160, and there are some on Evilbay for $140. I won't be so inane as to ask for advice, but can it be confirmed that all my answers lurk in this thread: http://forums.hybridz.org/showthread.php?t=104735 there are a lot of 280ZXs in the local yard, occasionally some RWD Maximas, once in a blue moon an S13 (that's what you young pups call late 240SX's, right?) Quote Link to comment Share on other sites More sharing options...
bjhines Posted August 1, 2007 Share Posted August 1, 2007 Keep in mind that ross will supply you with EVERYTHING you need including rebuilt calipers. The 240SX rear calipers combined with the largest disks in his kit are a perfect match to the toyota 4x4 calipers and vented disks up front. I went through doing this myself including making the brackets. It WAS NOT WORTH THE EFFORT!!!! Also... get rebuilt calipers... I rebuilt my own and they were the most challenging damn things I have ever torn into. The first thing you will realize is that snap ring pliers WONT get the damn snap rings out of the bores. They used a special tool to do that at the factory... you won't find an easy way to completely tear them down. Quote Link to comment Share on other sites More sharing options...
kyle Posted August 1, 2007 Author Share Posted August 1, 2007 Hmm... innnnteresting. What's the cost from Ross with calipers? Are his Kevlar pads track worthy? *** Calipers shown below are not available to us at present. If this changes we'll update this comment. Picture below left in place for visual aid for customers sourcing their's (to date no issues from customers sourcing these in the US or elsewhere)The kit is $425, plus calipers, which surely would be in the $200 neighborhood. Now we're to $625. The RWD Max adapters are available new, $110 a set. Figure $80 for pads, $100 for decent used rotors and calipers. That's $300, and all bolt on, unless I'm misreading something. What's the match gonna be with stock fronts, either with MM kit or the late 280ZX? I'm tempted to just jump in and redo everything, but I really want to do the rears first; that way I can see what the rear drums really contributed to my brake issues. Then again, AZ Z car's wilwood stuff looks nice, and hell, it's only money. Gotta have something to do this winter. Quote Link to comment Share on other sites More sharing options...
katman Posted August 2, 2007 Share Posted August 2, 2007 If you want all the tricks to racing with stock calipers and drums go visit the Datsun forum at improvedtouring.com. Because of rules limiting ITS cars to stock calipers and drums, and the ARRC being held at Road Atlanta with it's nasty downhill braking zone for 10a (thanks Mr. Panoz, %$@#*), you'll find the last word on making the stock brakes work over there. But I'm all in favor of vented font and rear disks if the rules allow it. Quote Link to comment Share on other sites More sharing options...
bjhines Posted August 2, 2007 Share Posted August 2, 2007 If you are not class limited then you have a lot of options. Some issues to think about: The difference in price between the Willwood style brake kits and the factory style disk upgrades is not that much. Whatever you choose to do, make sure it is proven to have proper bias front/rear. If you are going to change the rear brakes then you might as well plan on changing the fronts as well. The main disadvantage of the brake upgrades using factory components is WEIGHT. The stock 240Z brakes are not great performers but they are relatively light. Those Toyota truck calipers are monsters and the rear disk kits are slightly heavier than the stock drums and backing plates. The larger vented front disks are also heavier than the stock pancake disks. All in all the Willwoods are the way to go for track use, but the lack of parking brakes make them unusable for the street. Quote Link to comment Share on other sites More sharing options...
kyle Posted August 2, 2007 Author Share Posted August 2, 2007 Really appreciate the feedback, guys. My car is somewhere between garage queen and neglected completed project car. It's found a niche as an track day car. I have a BLAST with it, which is interesting given its non-sexy suspension and tires. It's too fast and too fun to drive on the street... gets to 90mph WAY too easily; short version is the lack of an Ebrake is a non-issue. The sticking point is that good ole slippery slope. $300 for a JY ZX swap. Easy enough to rationalize the upgrade to the $500 SX setup. Hell, then I'm pretty close to $750 for the Wilwood for the rears. Dunno what the vented 4x4 setup costs, but I'd guess $300 with new pads. Again, a smallish step to the $750 Wilwoods. But now, the $300 upgrade winds up being $1500. Sure, but now I've got the brakes to support a turbo ($3000). And hell, that's $4500 into a $12000 restored car. $4500 could go a long way toward building a turbo Miata or other dedicated track beater. Sigh... Short short version is I'm not limited by class rules, just limited by $$$-restraint, mostly spousal-imposed. But since she runs our stock Miata on track days, I can't beat her up too badly, can I? //edit, I should add that with full interior, sound deadening, piston-style AC, and stereo, I'm not super worried about weight. I just don't want to spend $800 for vented/ZX setup and wish I'd ponied up the money for the Wilwoods. Quote Link to comment Share on other sites More sharing options...
kyle Posted August 2, 2007 Author Share Posted August 2, 2007 Well shiver me timbers. Those IT nuts use the Ebrake to take slop out of the rears during a race. That's so crazy it just might work. Maybe I'll run it up to Reno Fernely in October and see if I can make it behave... Quote Link to comment Share on other sites More sharing options...
kyle Posted August 2, 2007 Author Share Posted August 2, 2007 And just to keep bumping my own thread, it looks like the front vented set can be done for $350 F and $450 rear, or $300 for the ZX rears. Before I go nuts and start buying things - has anyone done the vented fronts with 15" Panasports? Quote Link to comment Share on other sites More sharing options...
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