Fixing rear air suspension questions.

[SiZ]

Hey guys and gals, just got my 'ol runner back from the shop doing the steering shaft replacement, and now I'm on to the next problem. I lean to the right quite a bit at the back, and I'm suspicious of the rear passenger height controller. I asked the guys at the shop to have a quick glance at it, and he agreed, but he also said that my bags look like shit, and they're all cracked and corroded too.

So, I know that everyone just does springs in the back, but I don't want that. I like the bags. The reason I have my runner is to tow my boat and when its all loaded up, the bags are sick.

Wondering if anyone here has actually dedicated to repairing the bags instead of replacing them? The parts aren't particularly expensive it seems (as long as you don't go to a stealer), on rockauto you can get the bags, and the controllers, each component seems to be about 150-175cad, the whole total is just under 700 for new everything.
Does anyone know about those particular parts I'm talking about?

Also, hidden wtb post. If anyone has some components that are in good shape (I'm looking at you, southern states guys) that they want to clear out space in the garage, slide in my DMs.

Thanks for the time, I'd love to hear any and all thoughts.

 

[Keros]

At the risk of sounding like an idiot... I think the bags are just a big rubber structure with metal ribbing to keep their shape.

The bag itself either holds air or it doesn't. Maybe one could jam up and not move freely though?

It'd be much more likely that your ride height sensors are either done like dinner or simply need to be adjusted. In any case, if adjusting the sensor does not yield results expected as per the TSRM, then it could be the bags. The process requires a couple of wrenches, patience, and the section from the shop manual. Note that the sensors can be taken apart and serviced, which isn't that complicated to do.

When I tried to open mine up, the guts dumped out all over the floor in the form of tiny bits of rust (thus explaining the bizarre behaviour of my air suspension). So I had to buy new ones, and now I have a set of sensors that only have a couple of years on them, that I paid heinous sums of money for and now collect dust on a shelf. Plus the rest of the air system that was original but in good shape. I switched to standard coils and billies last year.

 

[J-Roc]

At the risk of sounding like an idiot... I think the bags are just a big rubber structure with metal ribbing to keep their shape.

The bag itself either holds air or it doesn't. Maybe one could jam up and not move freely though?

It'd be much more likely that your ride height sensors are either done like dinner or simply need to be adjusted. In any case, if adjusting the sensor does not yield results expected as per the TSRM, then it could be the bags. The process requires a couple of wrenches, patience, and the section from the shop manual. Note that the sensors can be taken apart and serviced, which isn't that complicated to do.

When I tried to open mine up, the guts dumped out all over the floor in the form of tiny bits of rust (thus explaining the bizarre behaviour of my air suspension). So I had to buy new ones, and now I have a set of sensors that only have a couple of years on them, that I paid heinous sums of money for and now collect dust on a shelf. Plus the rest of the air system that was original but in good shape. I switched to standard coils and billies last year.

That’s exactly my situation and what I’m afraid of.
I associate the crazy behavior with the ride height sensors. I plan on attempting to service them as well. Any advice on this since you have taken those steps already? Any pix of the location? Obviously pix taken before you did the swap.
Also, worst case scenario...would you like to get rid of those dust collectors sitting on the shelf?

 

[r32]

Air suspension pdfs
https://bit.ly/2Gy7BQp

Search page for 'air supsension' and you'll see all the links to the PDFs. download/save the ones you need, then review.

 

[Keros]

That’s exactly my situation and what I’m afraid of.
I associate the crazy behavior with the ride height sensors. I plan on attempting to service them as well. Any advice on this since you have taken those steps already? Any pix of the location? Obviously pix taken before you did the swap.
Also, worst case scenario...would you like to get rid of those dust collectors sitting on the shelf?

Hey J-Roc,

Sorry man, I didn't take any pictures of the service attempt. I had the shop do the install of the new ones... funny though that their alignment machine gave them the right numbers for the wrong specs. I ended up having to adjust the ride height myself after bashing the rear axle off the bump stops and realizing the ride height was way too low.

I had the shop do the install because getting one of the sensors off was such a bugger, I didn't want to mess around with the other. Love them rusty Alberta trucks...

Yeah, I'd love to get rid of them dust collectors. If you confirm yours are toast, we can work something out. Send me a PM.

However, speaking from my experience, I don't know if fixing the OEM RAS is really worth the effort unless you REALLY like it. Now I'm not really sure if my experience is unique, but the RAS system did not like my billie kit at all. I put on the 6112/5160 kit (I think that's the model numbers... the fancy pants ones anyway); to replace my totally shot XREAS system. And the RAS absolutely did not like the bilsteins at all because bumps would trounce the rear axle off the bump stops. Pretty much any sort of large undulation of pavement would make the rear end hit the bump stops.

I was perplexed. I researched, measured, did more research, checked specs... double checked the specs on the ride height, and yeah, it was set at stock height. The shop jacked it up another inch and that made it alot better but it then rode rough as heck.

I considered custom bags that would permit longer travel for a while... but I decided I didn't want to cut new ground on a project. I took the path well traveled with Metal Tech's RAS conversion kit and wheeler's offroad super bump stops. Ordered a set of Moog rear springs from Rock Auto and threw all that in myself in a weekend.

In the end, I could not find anyone who had documented anything correlative to the circumstance I encountered during the swap: that without the XREAS, the rear end would slam the bump stops. I could only assume I messed something up along the way or most people ditch the RAS with XREAS, while those that don't sort of learn to live with the issue or pump up the bags to avoid bottoming out.

My only hypothesis is that the XREAS stored potential energy in the hydraulic accumulators that were between the two connected shocks, lending oil pressure when needed to prevent a shock from hyper compressing or extending; thus the XREAS shock would momentarily increase the spring rate to cushion the bottom-out scenario.

I think... I recall reading somewhere that to have RAS one needed to have XREAS as well. If untrue, though, I have no idea how that rig would run with the same setup my rig had.

Long story short, I concluded that my pea-brained hacking up of Toyota's finely engineered suspension system of the XREAS & RAS was not going to work out unless I went full redneck on it and ripped the whole thing out and went to just good ol' standard coils and shocks.

Which brings me to my final point: your XREAS system will die sometime and Murphy's law determines it'll be right after you spend a bucket of money on fixing up the RAS, like I did. Uh, well, I did get 2 extra years out of the XREAS & RAS after replacing the sensors, though. I exaggerate a smidgen here, sorry.

Sorry, I get real wordy sometimes.

 

[TowMeOut]

Coil springs plus adding the Firestone Coil-Rite airbags (if you really need them for additional weight) is gonna be about $200. I threw some secondhand FJ springs on the rear plus the airbags. Most days they run soft at 5-10psi. If I'm pulling a heavy trailer or loading up the truck for a weekend camping trip then I might throw 20psi in there. Takes just a sec. No sensors, no electronics, no compressor.....(other than the one in my garage).

 

[RobD]

Interesting. I'm running the 6112/5160 combination on my 4Runner with rear air bags and don't seem to be hitting the bump stops. It's firm, I'll grant you that, but with the XREAS, my kidneys routinely took a beating.