mws

Air bags are simply a variable rate spring. The more air pressure you add, the higher the spring rate. They are also a progressive spring. Sized properly and used wisely, they are a wonderful addition to trucks that are asked to perform variable functions. Personally, I hate air shocks. Because the piston area is so small and the resulting spring rate is a function of the area and pressure, you need a huge amount of pressure to get a minimal amount of additional spring rate. And the high air pressure in the shocks tends to cause a lot of stiction in the shock, degrading the ride quality. The average air shock has piston size under an inch, whereas most airbags are in the 3" to 6" diameter range. A 3" piston has almost 10X the area of a 1" piston, so it takes 1/10 as much pressure for the same load increase. BTW, you can get quite a bit of ride height increase with bags with proper installation, but at a serious cost. On my tow van, I get over 3" of lift with the bags inflated and no load! But then I have the spring rate and ride quality of an unloaded 1 ton truck. This is the intended and ideal application for air bags - extra load capacity. Although it is a 1 ton drivetrain, I am using 1/2 ton springs with airbags. When empty, I run 10 psi and the ride is almost Cadillac smooth. When we're headed out for a weekend, I air them up to 80 psi and crank the damping on the RS9000's to max. We throw 2 dirt bikes, 50 gallons of water, all our gear, and firewood in the back of the van. Then we hitch on our trailer (with well over 500 lbs tongue weight!) and it ends up right back at the original ride height. And still rides great - far and away the most stable, comfortable, and controlled feeling tow vehicle I've ever driven. My BIL's F250SD was close, but it was so tall it felt far less stable when cornering. IMO, they are a nice addition to the Pathy when used in moderation and with stock or not much stiffer than stock springs. I still have stock smooth ride when empty, but can firm it up whenever I want...

Just for the record, I like the stock spring rates for normal driving. I plan to add about 3/4" spring spacer for a little lift, and a 1.5" airbag spacer. From what I've seen in my experiments to date, a reasonable amount of air should get me up to about 1.5" of lift for offroading, and a lot of air should get me over 2 or 3" if I need max ground clearance.

I think he was talking about the pucks for use as air bag spacers, they sit inside the springs. Yup. What he said. If you're really worried about spacers shifting (and it sounds like you don't need to be...), just drill and tap a couple holes to locate them. Even a 6mm or 8mm bolt would be more than enough to keep them in place no matter what...

I'm using the Air-Lift bags. They work perfect for adding load capacity, exactly as designed and claimed to do. They can also be used to raise the truck a bit - but as installed per the instructions, it takes quite a bit of air to get much lift - like 40+ psi. At which time it starts riding like a truck using add-a-leafs. Buckboard stiff and jarring ride due to too much spring rate. Here's my plan: Install about 1 to 2" of plastic spacers between the bags and the spring mount (think hockey puck). Then adding air adds more lift sooner. Going to do it, just haven't had time yet.

As with most things, it depends! Usually you want narrower to penetrate down through the snow and get more traction. The exception is REALLY deep and hard packed snow that you want to stay on top of - like in Alaska!

We were out exploring some hot springs and abandoned mines out around Austin and Eureka a few years ago with some friends in (sheesh, I'm embarrassed to say this...) a Chrysler minivan. Yup, a minivan. OK, now that I've exposed that part of my past... It actually did a remarkably good job! Did great on the hard pan and gravel roads, and even crawled up some pretty steep trails - in reverse! Fantastic climbing ability in reverse. All of the weight is on the drive wheels then. The only challenges were rocks, high centering, and sand washes. Even as light as the minivan was, we really struggled in the washes. That is the only thing I feel I am not totally prepared for... I'm being much more prepared than necessary, but that's the way I am. As long as I need to get tires, might as well get the absolute best for the job. I'm sure the 31x10.5 will do just fine, but if I can get even better for not much more, what the heck! Just your average ex-boy scout graduated into an anal retentive engineer...

And it is a LOT easier to watch the lights if you take the passenger seat out. IMHO, it's well worth 5 minutes of wrench spinning to get the seat out of the way.

Yes, there can be significant improvements, especially in vehicles with poorly designed intake tracts. Chevy trucks (for one) are famous for "convenient" intakes rather than "free flowing" intakes. And if you compare a new K&N (or ANY brand) to a dirty filter, it makes a very noticeable difference. That is how the majority of those comparison charts are generated: Run the vehicle using stock filter (don't mention it has 50K miles and is black!) and then swap in brand new brand X filter and test again. WOW! This is called "marketing". Learn to recognize it... As far as actual examples: I learned on dirt bikes. A buddy installed a K&N in his XR-350. About 2K miles later, it started running poorly and then got worse and worse. Lots of debugging finally revealed the needle was "hourglassed" and the needle jet was "ovalized". What happened? The fine granitic dust that the K&N passed would stick to the damp needle, and as it slid in and out of the jet, it effectively filed everything down. Extreme application, yes. Just consider it an "accelerated" wear test. If you drive in minimally dusty areas, or in areas where the soil is NOT ultra hard silica, the wear caused by the dust passing through the engine will be MUCH reduced and you may not see any ill effects for many thousands of miles. Another quicky test you can do yourself: Smear a really thin layer of grease on the intake pipe past the filter. Install a new (OEM quality) paper filter. Drive 5K miles. Wipe the grease with a white rag. Notice how dirty the grease is. Repeat with K&N filter. Make your own conclusions. I have (see previous post). NOT telling you what to do, just trying to help you make your own decisions based on facts, not marketing hype.

Yup, that's the Air Injection Valve. I think a piece of heater hose would work just dandy to repair it.

In figuring out the luggage rack for my '87, I noticed the little 4x4 emblem on the side behind the doors is in a pretty good spot to mount the crossbar. It would be cool if I could use that emblem as a cover over the mount holes when the rack is not in place. How is that emblem attached?

Before you install a K&N or any other cotton gauze knock offs, you owe it to yourself to read this: http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm The Reader's Digest version: They do flow more. A little more air, and a lot more dirt. And they plug up a lot faster. Up to you to decide if the frequent servicing and dirt ingestion (and resulting shortened engine life) is worth the (possible) performance improvement. I used them on my track bike as it made a tiny little improvement and I only put a few hundred miles per year on it. Never in vehicles I plan to keep over 100K miles. Expecially where I live - the dirt is mostly decomposing granite from the sierras - which is very hard and very abrasive. I just change the paper filter frequently.

Thanks, all! Since I am buying new wheels (the old ones have a lot of rust), I can get the optimal backspacing. So what do you think would be the optimal backspacing for the Kumho 31x11.5"? I'm thinking 3.5" to prevent rubbing on the inside, but will that lead to more problems rubbing on the outer fenders and flares?

I did a search, but this seems to be the one question I didn't see answered! So I'm getting closer to buying a set of serious off road tires to be used on adventures only. I had it pretty much narrowed down to the "new" Cooper STT in 31x10.5-15 with a 4" backspace 15x8 steely. '87 XE. And then I noticed that Kumho offers the Venture MT in a 31x11.5-15.... A little wider would be better for flotation in the Nevada desert, no? But will they fit without a body or more extreme suspension lift? I cranked the T-Bars a little and lifted the rear suspension an inch or two, but that's as high as I would like to go (for a number of reasons). 31x10.5-15's fit fine but were close. Can I squeeze one more inch of width or will I get fender rub in tight turns? Will a simple plastic trim fix it, or is it metal whacking time?

Reviving an older thread here... So has anyone actually tried the new Cooper STT? Impressions?

It's a little annoying. I replaced the clutch slave cylinder in Feb, and the master cylinder in April. I put a dab of grease on the end of the MC pushrod, and greased as much of the pivots as I could while I was in there. A couple months later, a noise started abruptly. When depressing the clutch pedal, it emits a creaking pop sound when about 1" from the bottom. And as I release the clutch, it does the same about 1" from the top. So it happens at different parts of the travel on the way up and the way down. Sounds like it is coming from up under the dash. And moderately loud, as well. Can easily hear it over road noise, and need to crank the stereo very loud to not hear it. I sprayed the pivots and helper spring with a spray lubricant to see if it would quiet down, but no change. I suspect the helper spring may have slipped or broken, but I can't see anything obviously amiss. And of course, sounds travel so the source could be in the MC itself... Any ideas??

Hmmm.... Maybe Nissan transmissions are better designed than GM? Well, duh... No surprise there! How do you know there is no air? I tested mine after another guy advised me I should. I ran cold water over the cooler for about 5 minutes after a long drive. Then I started it back up and put my hand on the cooler. The top 1/2 remained cool for quite a bit longer than the lower half because the lower half had hot fluid pumping through it whereas nothing was flowing in the top due to all the air trapped in there. I drilled and tapped a new outlet fitting in the top and tried the same experiment. The whole thing heated up evenly.

I ordered 2.5" core Dynomax muffler and cat from Summit for under $150. Local guy had no problem installing it all for me and bent up 2.5" pipe to complete it. But some shops won't 'cuz they're greedy. So use this as a great filter for selecting the shop to do the install. If they won't do it, consider yourself warned that they're greedy buggers and thank them for telling you so! And thank you for running the cat. Although a lot of clueless folks say they hinder performance, a good cat will NOT hurt performance. Some of the really poorly designed ones put out in the 70's and 80's were restrictive, but competition has corrected that. No cat WILL hurt the environment and you. Without a cat, the tailpipe emissions are far more stinky and hazardous to your health.

To try to fix it, soak it down with PB Blaster and let it sit in the sun a few hours. Or just go to a junkyard and find a similar jack, but one that will lift higher. Most yards effectively give them away...

Don't know... with the tall tires, I found the stock jack could barely lift enough to do any good. So I hucked it and carry a Hi-Lift.

I would, but I have additional brackets attached to it to hold stereo amps and it ends up being horribly hard to see anything meaningful. It does have quite a few interesting bend and angles to it. I'm not sure I would want to try to reproduce it... I would spend a little more time perusing wrecking yards first.

And hear is yet another theory: I like to put an auxiliary trans cooler BEFORE the one in the radiator on vehicles that tend to have engine overheating problems. Since the amount of heat removed is dependent on the differential in temp between the fluid and the air, the cooler does the most when the fluid is hotter. By pre-cooling the fluid before it hits the radiator, the radiator water does not get as heated up by the trans and the engine is less likely to overheat. Also, if you drive in cold areas, running the coolant through the radiator cooler after the auxiliary cooler "rewarms" the fluid back to nearer the ideal temp. In my tow van, I have 3 aux coolers, two before the radiator, 1 after. 1) Big plate style mounted alongside the radiator since there is room there on a full size van. 2) Big tube and fin style in front of condenser. Yes, this pre-heats the air a little bit, but really not that much... 3) Through the radiator cooler 4) Through the biggest plate style I could find, mounted under the truck with an 8" electrical radiator fan. The fan is manually switched on when going slow and tranny is getting hot. 5) Ultra high flow filter with 1 quart reservoir Of course, if you want to try to add this much stuff in line, you have to worry about fluid restriction and loss of flow. I used massively big coolers with oversize passages, fittings, and hoses, and checked the flow rate before and after installation (temporarily put a piece of clear hose in line to watch) to assure I still had adequate circulation. The engine coolant temp used to get dangerously high about the same time as the transmission. Now, neither one gets even close to too hot - even on 15% grades on 110 degree days with trailer in tow... To purge air, always mount the cooler so the outlet is as high as possible. Then they are self purging. Most trannies occaisionally whip up the fluid a bit and get some air bubbles in stream. If the inlet and outlet are both on the bottom of the cooler, the air bubbles will settle at the top of the cooler. I had to drill and tap a second outlet on one of my B&M plate coolers and plug off the original outlet because the only way to mount it meant both the inlet and outlet were at the bottom. Within 6 mos, the cooler was over 1/2 full of air.

You see what I see? Oh yeah, a whole new forum for OFF TOPIC stuff! See you over there!

Oh, and as far as brand of cooler, I've heard there are basically only two manufacturers in north america - one that makes the tube and thin fin style, and one that makes the plate style. And then many companies buy from them and private label them. I greatly prefer the plate style. Much more durable, and seem to work better as well. B&M is the most popular company to buy from. Summit Racing is where I got mine. When you install, make sure the outlet is near the top so any air that gets in the system self purges.

HEAT is the number one enemy of automatics! While you have the tranny out, install a temp gage sending unit in the pan (braze, weld, or JB weld a bung if there is not one)and install a gage. I used an Autometer electric gage and am impressed. If you see temps over 250 in the pan on a regular basis or ever over 275 or so, do something quickly or start saving for another tranny. I ended up with 3 (yup, 3!) auxiliary coolers on my tow van to keep temps under control while pulling our travel trailer and motorcycles up the steeper grades on the way to some of our favorite playgrounds. The engine puts out over 450 lb-ft, which really works the tranny hard. $300 worth of coolers hurt, but that is much better than $3000 worth of tranny... This is an extreme example, but it illustrates that different applications may require equipment beyond what the factory installed.

"Rebuilding" an automatic seems to be one of the less predictable repairs. Sometimes they come out great and run for years, way too often they don't. Very complex little buggers that are asked to do a lot under tough conditions. Some designs are more successfully "rebuildable" than others. IMHO, the best bet is to find a relatively low mileage wrecked truck that had a great functioning transmission at the time of it's death and swap it. You can usually find complete trucks for less than a rebuilt tranny... Personally, I still prefer sticks (since I do not live in a city with traffic jams!) Right now, my nephew and I are in the middle of converting his VW Eurovan from auto to 5 speed. The auto died, and the history of rebuild reliability on these trannies is horrible. He had it rebuilt once, died again 20K later. Got all of the necessary parts (we hope) from a low mileage wrecked 5 speed for less than another rebuild.