Everything posted by Captain Obvious
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low fluid level rear brake reservoir 72 240Z
The small one.
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Brake rebuilding time. Lots o' questions!
I'm sure you already know this, but just because the fluid level in your master cylinder is low, doesn't necessarily mean that you have a leak. At least not with simple disks like in the front. The volume behind the caliper pistons increases as the pads wear, and that extra volume is taken up by brake fluid from the master cyl reservoir. With rear drums, I guess it's not that clear... The rear wheel cylinders should always relax to the same position, so there shouldn't really be any change in the reservoir level at rest, but if your rear adjusters weren't working properly, that may not have been the case. The rear pistons may not have been pushed all the way "home" and you may have used some of the fluid from the tank to take up the extra volume. I know, I'm reaching here, but that's all I got. (On edit): Actually, thinking about it some more, the rear cylinders push directly on the shoes, not on the adjuster mechanism. So the pistons should not be pushed home as the shoes wear. The adjuster mechanism should hold the shoes apart, so I guess the same situation exists in the rear as the front. The brake fluid in the master cyl will drop as the shoes wear. What you could end up with if the adjusters aren't working correctly is excessive pedal travel. Only other info I've got would be that I've seen the same white crumbly corrosion on aluminum brake parts in the past. My theory is that it is a slow leak, and the brake fluid (being hygroscopic) is attracting moisture from the atmosphere and that combination of brake fluid and water is causing the aluminum to corrode. In any event, with all the issues you did find, it sure wasn't a wasted effort!!
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Brake rebuilding time. Lots o' questions!
I agree. Must just be a mistake in the docs. Sure is a good thing that I don't read directions, or I may have followed them!
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Brake rebuilding time. Lots o' questions!
You're talking about the pre-77 rear cylinders, right? They're very different than the 77-78's. I'm sure that spring you're talking about is supposed to fit narrow end snugly around the locating boss on the back of the piston and the wide end pushing against the inside of the cylinder. You're saying that all the pictures show that spring installed wide end against the piston???
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Brake rebuilding time. Lots o' questions!
Actually the rear disks with the parking brake that would stick on was not the "mini-drums inside the rotor" style. They had the parking brake function built directly into the caliper. The concept was sound, but they used some stupid roller bearing on the parking brake pivot shaft that would rust in place to the shaft. Hope it turns out that your flare isn't leaking. Out of curiosity, you originally started this because you were chasing a low fluid level in your master cylinder. Did you ever find the smoking gun for that?
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Brake rebuilding time. Lots o' questions!
Wow. Three test parts and you're getting good doubles. I know who I'm callin' next time I need a hardline replaced! Glad you got the adjusters figured out. Lube em up and, keep them dry (backing plate boots in good shape) and use the parking brake frequently enough to keep everything mobile. Doesn't have to be every time, but more than once a month. I've been inside lots of drums over the years, and I gotta say that the late 280's are one of the better ones. It's the simplicity, and the room to work. Don't hate the drums... As a matter of fact, I've had other cars with rear disks that I was actually afraid to use the parking brake because it would intermittently get stuck engaged. It was a bad combination... Steep driveway, manual transmission, parking brake that would stick ON, and a very worn engine with barely any compression left. Do the math.:paranoid: It was like Christine.
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Brake rebuilding time. Lots o' questions!
Phew... Right before I hit the post button, I realized how long that post was. I was worried that I was off track. When did I become so wordy...? :tapemouth I've had a bunch of flaring experience also, and it's a pain. Thankfully, I've never done enough of it to warrant buying my own flaring tool set, so I borrowed a double flaring set from a buddy and found that the mandrel that came with the cheap double flaring sets is crap. It didn't fit well into the tubing and was almost impossible to get decent results. I finally gave up and turned my own mandrel that was tight fitting into the hardline tubing. Results turned out much better. I would hope that the more expensive flaring sets have better accessories. Even so, I bet there's significant finesse that must be learned before getting good results. Make a complete single flare first? Make a partial single flare first? Make half the bubble flare and then rotate the tubing 90 degrees before finishing it? Now that you've been through it, you know the drill.
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Brake rebuilding time. Lots o' questions!
Been a while, so I'm going from fuzzy memory: The 77-78 rear adjusters... Assuming there is enough travel as to require adjustment: When you APPLY the parking brake, the adjuster lever hooks a tooth on the wheel and turns it. When you RELEASE the parking brake handle, the gear wheel should not move and the lever should ratchet past the teeth on the gear. You should be able to hear the lever "click" as it snaps past the teeth on the gear. The teeth on the adjuster wheel and the location of the lever is designed such that there should only be rotation in one direction and that direction is different for each side of the car. So you really don't have to do much pre-adjusting on the adjuster wheel before you put the drum on. Just get the drum on, and then pull and release the parking brake handle a whole bunch of times until you stop hearing the clicks on let-off. Goes like this: Pull up - Hear some creaking from the cables and springs and such. Release - Hear three (if memory serves) clicks as the adjuster lever ratchets past the teeth on the gear. Pull up - Hear some creaking from the cables and springs and such. Release - Hear three clicks as the adjuster lever ratchets past the teeth on the gear. --- Repeat the above a couple of times until --- Pull up - Hear some creaking from the cables and springs and such. Release - Hear TWO clicks as the adjuster lever ratchets past the teeth on the gear. --- Repeat the above a couple of times until --- Pull up - Hear some creaking from the cables and springs and such. Release - Hear ONE click as the adjuster lever ratchets past one tooth on the gear. --- Repeat the above a couple of times until --- Pull up - Hear some creaking from the cables and springs and such. Release - Hear NO clicks. You're done. From that point on, as the shoes wear and the travel increases, you will eventually reach the point where the parking brake lever will cause one click on release and then the next time you apply it, it will adjust one click. Does that until you replace the brakes next time or rusts solidly into place. Since the rear of the car is already off the ground and the wheels are off, I usually pull off the drums again and just have a quick peek at the shoes and make sure they are aligned pretty much in the middle of the backing plate. Wiggle the shoes around a little bit, "unadjust" the wheel a couple of teeth, put the drum back on, and adjust them again. If your shoes need a lot of adjustment (meaning they are pretty far from the drums) you should hear multiple clicks when you release the handle, and if you're not, there's something wrong with the adjuster system. I apologize if I answered a whole bunch of questions that weren't asked... I was on a roll.
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240z undetectable coolant leak
Not to be a smartass, but if the radiator is always full..... Are you sure you're looking for a coolant leak? I once had a car that would lose coolant slowly over time, and I spent years looking for that leak. Never a spot on the ground. No signs of coolant anywhere in the engine compartment. Compression test turned up no clues. Turns out that I had a tiny tiny pin hole in the radiator, and it would only leak when the engine temperature and coolant pressure peaked after you shut it off. A hair thin stream of coolant would spray out of the front of the car, cleverly missing even the grill slats, leaving behind no trace of wetness anywhere. It hit the ground about five feet or so away from the car, half of it probably evaporating before it ever even hit the ground. I finally discovered it one day when I was standing a couple of feet in front of the car and noticed a slow growing warm wet spot in my pants. It turned out to be my car whizzing on me. That's my story and I'm sticking to it. On that occasion anyway!
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Help needed ASAP
Don't get me wrong... I'm not questioning the belief that there are materials better suited to this application than Delrin. I'm sure there are LOTS of better choices. I just happen to already have Delrin in stock and it's very easy to work with, that's all. I picked that one for all the wrong reasons. Kinda like looking for your car keys where the light is good. And again, I'm not pushing for Delrin or anything, but if I'm reading the datasheet correctly, they list the melting point at 175C. That ought to be enough, right? Does look like fun. I drove a Fiero for years and years and I feel for that guy. I think I've talked with him in the past.
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Help needed ASAP
Yeah, that's a good point about the exhaust manifold. It's hot. As for what to make the insulators out of... I was thinking Delrin (acetal) because it machines like a dream. Well, that and I have it on hand. Haven't checked the thermal conductivity and it's probably not as good as ceramic, but it's gotta be a whole lot better than steel!
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Help needed ASAP
I'm not a thermo expert but I'm skeptical about the amount of heat that is conducted up through those mounts. I guess any little bit helps though, right? In any event, After you drill the mount hole larger, I'd be happy to make some plastic insulating inserts for you once you get to that point. Now that you aren't using the mechanical fuel pump at all, how about completely re-routing the fuel lines across the firewall and onto the driver's side fender instead. Don't ever mount it to the block at all. I'm sure I've seen pics here on the forum somewhere of that mod.
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Brake rebuilding time. Lots o' questions!
Unfortunate to think it might come to that, but yeah, that would be a tough sell.
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"White" seat covers?
Cough... Cough... "Shipping: $34.50 Expedited Shipping" $35 bucks for shipping??? This kind of shipping cost gouging is a perfect example of why ebay started charging sellers a percentage of the shipping cost. I mean, if the sales price is low enough and the bottom line is acceptable, then it doesn't really matter. It's just annoying. :disappoin
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Help needed ASAP
Absolutely. That's beyond "respectable" and into "enviable". I looked at the float geometry last night to refresh my memory, and I'm not seeing an obvious explanation for mixture changes under lateral G's. At least nothing that wasn't symmetric side to side. Because of the direction of the float hinge pin and the position of the hinge on the float itself, I could maybe see something under hard acceleration or deceleration, but side to side isn't obvious. Not saying there isn't a relationship, just saying that it doesn't jump out at someone not trained in the art like myself. I'd love to hear what the experts like Steve and Bruce at ZT say when you talk it over with them. I thought of something I should have suggested a long time ago... When you are having the stuttering problem, have you reached for a handful of enrichment cable? That could tell you if you are rich or lean while the problem is occurring. If the problem clears up when you pull the choke and lower the nozzles, it's pretty clear that you are starving for fuel. Vice-versa for making the problem worse if you're already drowning. Out of curiosity, what was your average gas mileage? You said your drivers were getting roughly 1.5 hours out of ten gallons of fuel. About how many miles is that?
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Help needed ASAP
I've never personally messed with a wideband, so I'm not qualified to provide suggestions there. I did come up with a question about the problem in the turns though... You said that it goes rich mid-turn. Are you already on the gas at that point when it starts acting up? I, for one, am glad that you are sticking with the L26. Frontrunner or not. You're period accurate, and I think that adds class to your team. Of course, that doesn't add any speed, but I think it adds credibility.
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Help needed ASAP
Hi Jeff, Thanks for the fantastic race report. Congratulations on your finish position, and your Mr. Clean award! Sounds like a load of fun, although frustrating at times. That's the problem with not being able to test under the actual use conditions. I know it's way out of your budget, but could you run a wideband? After the stuff you describe, it's unclear if you are running too rich or too lean. Your 5:00AM discussion buddy thinks it rich, and backfiring on decel and your glowing manifold would corroborate... You could use it for test and practice laps, but then take it off for the actual race laps? Would that count against your $$ ? So what's the bottom line on performance... When it's cold, it runs great. No stumbles at all and no restart issues. Makes power all the way to 6500 RPM. When it's hot, it stumbles out of turns (right turns only?) and is hard to restart hot. Breaks up above 5000 RPM. Are you running any of the original emissions controls? I assume you've already nuked EGR and air pump, but are you still running AB valve or throttle opener controls? I'm thinking that the elimination (or non-functioning) of those two might load up the plugs and exhaust manifold with unburned fuel on deceleration. And I agree that a vented hood would be a good idea in the future. Probably won't do a whole lot once you're up to speed, but could help a whole lot at low speeds and when you are stopped completely like at pit stops and driver changes. Especially if you've got to keep the engine running for five minutes while sitting dead still.
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Help needed ASAP
Sounds fantastic. Well, other than the vapor lock stuff of course. Looking forward to the full report!!
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SU Jet Depth Calculator with Temperature and Altitude Compensation (XLS Tool)
I think you are being overly concerned. Sync is air volume (basically) and nozzle wheels are fuel. Changing the nozzle wheels shouldn't do anything to change the volume of air, and hence should not require a re-sync. Of course, if you have the time, there's nothing wrong with doing it anyway. Don't cost nuthin'. Out of curiosity, have had to make significant sync changes after messing with the nozzles? (Assuming, of course, sync at the same RPM...)
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Drivers side hinge detent roller - 77 280z - loud pop when door opened
Use mine? Are you nuts? I'm not going to use my own car as the Guinea Pig!! That's why I suggested using yours! Seriously though... That problem on my car is so far down the priority list that hopefully I'll still be alive when my car gets to that level of repair. I'd be happy to use mine, but I've got significantly bigger fish to fry!
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Sealing Hole in Transmission Tunnel at Handbrake
Nice. Was there originally some kind of seal there when new, or was it never sealed at all?
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Drivers side hinge detent roller - 77 280z - loud pop when door opened
Jim, My driver's side is just like yours, and I believe you hit it exactly with the above. You can lube it all you want at this point, but as soon as it rotates around to the flat, you're back to where you started. I'll offer up another alternative... If you want to rebuild your original hinge - Take it apart, send me your old roller as a template, and I'll make you a new one.
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Brake rebuilding time. Lots o' questions!
Haha! I did something similar a few years back with my piece-o-crap daily driver. I wanted to get just one more year out of it before I retired it, and I knew it "shouldn't" pass inspection. I cleaned it up all sparkly like before I took it in. The plan was to distract the mechanic with brilliance so that maybe they wouldn't see as many imperfections? It passed, but I'm not sure if it would have failed if it were uglier. You don't ask questions... :laugh: About your hard lines - I've had to replace the rears that wrap around behind the backing plate. They didn't rust through, but they twisted off when I took off the wheel cylinders. I tried my best to salvage them, but could not. They weren't all the way through, but were compromised by rust and that's why they were so weak. I made replacements from parts store tubing. If you're asking "Should I go looking for trouble?", my answer would be to play it by ear and give everything a good look over while your back there, but I wouldn't replace them simply because they're old.
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Help needed ASAP
Excellent. I hope you have those issues licked and have all the horses you're supposed to have. No rolling chicane for you!! Good luck!
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Brake rebuilding time. Lots o' questions!
I know that PA's regs have no bearing on your situation in VA, but you got me curious about those braided lines... In expected fashion, PA's regs are governmentally vague and do not specifically exclude the braided lines. There are essentially two parts to the regs that pertain to the brake hoses: 1) Brake lines shall be approved for use as brake lines. 2) Reject if - The hydraulic hoses or tubing leak; is flattened, restricted, insecurely fastened, improperly retained; or have exposed cords. If they are DOT, they should be OK for the first part, but the sticky part is the visual inspection part. The story I've heard is that some mechanics say "Because of the braided jacket, I can't see the hoses. Can't see 'em, can't inspect 'em. And because I can't inspect 'em, I have to fail 'em." From what I gather, PA's inspections are tighter than a lot of other states. And they've gotten way looser today than they were years ago. Anyway, thanks for the spur to look into it, and good luck with the upcoming brake work!