Slartibartfast

Good to have confirmation I did mine right too LOL.

I've got a slow leak on my '93. The past couple years I've added a can or two of 134a and brought it back to life. Not sure where it's getting out. One of these days I'll track it down and deal with it, but this is not that day. If it's an O-ring or something I'll probably do the lot of them so I'm not chasing one at a time. A friend of mine went a little overboard on his S10 and we replaced all of the aircon system. We had the dash out anyway to replace some vents and actuators and my friend decided he never wanted to deal with it again, so we replaced everything but the pressure switches. Turned out the compressor had fragged so at least half of what we replaced had chunks in it, so it was a good thing we replaced at least half of what we did. And now that it's done, it blows cold and probably will for the next twenty years. But yeah, I'd probably just tap the shrader with a pick and see if there's still pressure behind it, and if there is (meaning the system's not fully empty due to a massive hole in something), throw a can of 134 at it and see if that gets it going again. Then if it leaks down again, start chasing leaks. I'd probably avoid wrecker parts for aircon, given the hassle of putting it back together just to find out something doesn't work (or has contaminated everything else).

Mine's plumbed from the top hard line to the driver's side of the factory cooler in the rad, then the passenger's side is plumbed through the aftermarket cooler and the external filter back to the lower line.

I saw a guy on youtube a while back with a two-door who remote-mounted a turbo. IIRC it was basically under the truck. Seems like a bad idea for a wheeler but would get around the space issue without changing anything in the engine bay. That said, if you shift a few things around, maybe move the battery to the back, seems to me you could make a fair amount of room in the engine bay without losing the aircon.

Having worked on a 300-6 in an F150 I think you'd have to do a lot of cutting to fit that plant in a Pathy. It is one long SOB. The 3800 looks a lot easier to work with, provided you avoid the ones that catch fire. The supercharged version might be fun if you get lucky at the wreckers.

I don't see it in the AT section, but I wrote down that top was supply and bottom was return after I did the cooler on my '95. I plumbed my '93 accordingly and the it hasn't grenaded yet so I assume I was right.

It appears the celebration was premature. I got in the truck tonight, started it, and felt the pedal bottom out again. I jacked up the back and the brakes will stop the rears at idle (just like last night), but as soon as I tapped the gas, the bastards started spinning again. I don't know if I was distracted last night by how well the fronts were working or if I just saw what I wanted to, but I think I'm back at square one here. The new booster solved the weird noises and the front brakes work way better now, but there's clearly still something very wrong with the rear circuit. I had another look at one of my spare masters and there appears to be no way for air to leave the prop valve. All ports are below the centerline of the bore, and the bore is above the bore for the pistons. This makes me wonder if the master was just designed by gibbons and a couple bleed valves at the top of the prop would allow me to bleed the SOB properly and get the brakes back. Then again, swapping the rear line to one of the front fittings before didn't give me good pressure at the back either, so I'm not entirely convinced the problem is in the master. I haven't checked the small flex lines to the rear calipers yet. I'll take the rear wheels off, have someone press the pedal, and see if they bulge.

I'm glad it's over LOL. If my truck can stick to easy-to-diagnose breakdowns for a while, that'd be great. Msavides, good luck! Hopefully yours responds to the same treatment. You'll have to remove the master entirely to get the booster out, and even then it's a squeeze. I freed up a lot of room for maneuvering the booster by removing the siren for the car alarm.

Hole? What hole? Cut and weld or fiberglass?

My dad and I bled the brakes tonight. My dad noted that he could pump up the pedal against the air bubbles, which it wouldn't really do before. It also wasn't making nasty popping noises like it was before. It still made a little groaning noise from the check valve each time the pedal hit the floor, but the valve I got with the new booster makes the same noise if you blow through it just right, so I suspect they just do that, same as the rollover valve on the evap line from the fuel tank. We went in Nissan's bleed order, but also bled by cracking the fittings at the master, and got a little air out of each one. The pedal felt good after that but the rear brakes still weren't doing much. They'd stop the wheels, but I could push the tire with my foot and turn the wheel. My dad suggested we take it out, romp it, then try bleeding it again in case the rear circuit still had air in it. We took it out, did a few panic stops, and managed to lock the front wheels on dry pavement, which I'd never gotten this truck to do before. The next bleed got a bunch of air out of the driver's rear caliper. We tested it again with the wheels in the air and hallefrickinluyah--the rear brakes are back! I tore apart the old booster (straighten the waves in the ring around the back and it all comes apart without having to cut anything) and found that it was surprisingly clean and nice inside. The rubber diaphragms (it has two, which I wasn't expecting) looked brand new. The play in the output rod is supposed to be like that, near as I can tell; nothing on the output side was obviously damaged. Given the different part #s I suspect the one I put in is just a slightly different design. Some of the boosters at the wreckers had that play and some didn't. The one glaring issue I found was the internal air valve that makes the booster work. It was dirty (the only dirty part in the whole booster) and it caught and popped in its bore when I worked it back and forth. When you press the pedal, the input rod compresses a spring, pushing this valve spool into the plastic chunk it lives in, which allows air from the cab to fill the rear chamber of the booster, pushing the diaphragms into the front chamber (which is under vacuum). The plastic chunk pushes forward against the output rod, both from the force applied to the pedal and from the force applied to the diaphragms. I'm not 100% sure how this cluster unfolded but my best guess at this point is that the booster inhaled something it shouldn't have, which I pushed deeper into the valve while bleeding the brakes, which made the valve bind and catch, which limited the effect of the booster, which limited brake pressure, which wasn't high enough to activate the prop valve, so the rear end didn't get enough pressure to do much of anything... and what I thought was the master bottoming was actually the the valve catching in the plastic and trying to push the brakes directly without vacuum to back it up. TL;DR the booster was hooped and my brakes are back! Thanks to everyone who followed this clown show and threw suggestions at me. Hopefully this thread saves someone else from spending two months pouring brake fluid on the floor.

Yep! Picked up a booster today from a '93 4x4 HB, which I'm pretty sure had the four-banger in it. Same diameter, different sticker, though one of the numbers matches. It bolted right in and the output rod doesn't have the 1/8" of lateral play that my old one does, so we're hopeful. Tomorrow we'll bleed the SOB (ran outta time today) and see if anything has changed. Also to update my last post, we tried a wrecking yard caliper in place of the passenger's front reman and it didn't change anything. Guess that's the upside of throwing parts at it... you end up with lots of spares.

Dang. Might be hard to see the end of the pulley but if you can get your camera phone in front of it, you could probably get a picture and see if the keyways are lined up or if they're shifted. That would at least give you some idea of what you're up against.

Cool video! That thing had some serious kibbles and bits going on inside. The factory trans cooler is inside the lower rad tank. It transfers the trans heat to the engine coolant. I didn't bother dropping the pan on my '93. I just unhooked a cooler line, ran the engine until it quit pumping, added fluid, pumped it out, and repeated that until the fluid coming out looked clean. The old fluid (after 231k miles if it was original) looked good on the stick but it was brown in the bucket and I saw a little metallic shimmer when I first disconnected the cooler line. I put it back together with an aftermarket cooler and a Magnefine external filter to hopefully catch whatever small particles of crap the flush didn't get rid of.

Good luck! You got the blacklight too, right?

What kind of puller are you using? I used the duck's foot style and it worked great. Hopefully your key isn't screwed up.

That's a pretty dramatic failure! Maybe it ingested something? David Carroll (Mr. 510) is active on the NPORA Facebook page, you might try getting in touch with him there. Today my dad called me from the wreckers to say they have a brake booster, and the output rod doesn't have the lateral play that mine does. I'm hoping that means mine is in fact what's been running me through a knothole sideways and a $35 used part will get my truck back on the road. I'll find out this weekend.

These guys do a pillar gauge pod for these. Pictures/reviews here. I think the only thing the stock ECU does besides control the engine is send info the trans computer (if you've got an auto trans), send a signal to the tach, and control the check engine light. I'm curious how the tach's hooked up but I wouldn't be surprised if the Megasquirt could send the same signal the stock ECU does. I'll bet two atmospheres of boost wakes a WD21 right the hell up!

one of us one of us one of us

Fixing the problem is often easier than finding it! If I knew what was wrong with my brakes, they'd be fixed by now. A UV dye would make the leak easier to find, provided it's somewhere you can shine a UV light on. People do the same sort of thing to find air conditioner refrigerant leaks. The pressure adapter means you can pressurize the system without warming up the engine, so the coolant that escapes doesn't just boil off. I'd be inclined to jerry rig something with a blow gun and a pressure regulator rather than buying a dedicated test kit. A friend of mine had a fairly bad coolant leak in his van that took ages to track down. Turned out to be a ripped hose buried under other hoses and wires and whatnot. We never saw a drip and it only steamed if he ran it low and overheated it. I think he finally found the problem while working on something else. Good luck!

The last time somebody asked me that, I said 63/F/Long Beach Florida and the other person disconnected.

EL-41 of the '94 FSM says the oil pressure switch should have continuity if the pressure is 1-3 psi or lower.

I pulled the booster out again tonight and had another good look at it. Got the adjuster to move, figured out how to set its length, couldn't find anything wrong with it, put it back. The guy at the parts store told my dad a bad vacuum booster check valve could somehow introduce air into the braking system (push the pedal with the engine off and the booster pushes air past the seals or something), but given that my check valve seems to work and there's no air seal between the master and the booster, I ruled that out. The driver's front caliper that was letting off too far is off the truck, and the original is reinstalled in its place. I'd ruled the passenger's side caliper out after clamping the hose changed nothing, but then I pulled off the master again tonight and found a lot of air in it, which would explain why blocking various things off was not getting me anywhere. I bench-bled it again (they're a real pain to bleed, the prop valve is mounted higher than the main bore for some reason and there's no easy place for the air to escape) and installed/tested it with the plugs in. The pedal felt better. It would fall if I stayed on it, but the mess in the engine bay told me this was just fluid leaking past the bleed plugs (plastic plugs aren't meant to take full brake pressure? Who knew?). I hooked up the rear line, and the driver's front line, and it still felt about the same. Then I hooked up the passenger's front and the pedal went straight to garbage. That caliper is also the one thing I haven't tried screwing with or swapping out so far, so naturally it's the next thing I'm tearing off again. (And yeah, the leaky master in my '95 never caused problems other than fluid loss, either.)

Reverse is usually the first to go in these. From what I've read, the pump inside the trans starts to wear out, line pressure drops, and reverse needs the most pressure to engage. That's rebuild territory. That said, can't hurt to check trans fluid level and condition (with the truck warmed up). The trans computer also has some limited self-diagnosis. It'll flicker the light in the E-AT switch on the dash when you turn the truck on if it sees a problem.

My dad switched his to synthetic, just because it made the smoke cloud on warm starts a little less dense. It didn't seem to change the oil consumption any.

The muffler shops don't have pipe benders? You might check with any hot rod guys you know and see where they take their stuff for custom work.