RAS without XREAS? Help!

K

Keros

Member
Hello,

I’ve been lurking the forums for a while trying to find someone who has removed the XREAS and retained the RAS; as that I have (foolhardily) attempted such. I had the shop remove the XREAS (as that the system was completely done) and install Bilstein 6112’s up front on the lowest setting with 5160’s out back to match. They did not adjust the ride height of the RAS via the sensors and I had the ride height per “spec”, 3.11” difference in centerline of axle to centerline of trailing arm bolt.

Consequently, after changing the shocks, the truck moreless rode on the bumpstops. I had the shop wiggle the ride height sensors waaaaaayy down and now have the air bags extended to give me about 2” of breathing room between the top of the axle and the 4” tall bump stops. Unfortunately I didn’t measure the axle/bumpstop clearance prior to jacking it up as a stop-gap solution.

Has anyone ever successfully retained the RAS with standard shocks and gotten amicable/good handling characteristics? Obviously it’s possible, I drive the truck around just fine, but the front sails over speed bumps like they’re not even there and the rear proceeds to give me a chiropractic adjustment. It’s certainly not a practical/permanent solution.

At first I thought the Bilstein 5160 shocks had a longer extended length than stock and I was bottoming them out. The specs are 14.8” collapsed. I recovered one of the rear XREAS shocks and measured its collapsed length from center of eye to mounting surface to be around 15.2”… so that plot twist ruled out the shocks as the problem. It was just simply riding on the bump stop.

As it sits now, I have ~6” from top of axle to frame, the OEM RAS bumpstops are 4” tall, giving me 2” of free ride height. However, the pumped up bags give a pretty terrible ride.

My options are to get smaller bumpstops to increase ride height allowance and allow me to deflate the bags a bit to get better cushioning… or just bite the bullet and switch to coils and normal, sane length bumpstops. I’m considering either Timbren ABSTOREQ or Superbumps. I can only assume Toyota had a reason to put such long bump stops on the RAS trucks; presumably that the bags cannot compress/extend as far as a coil and would be damaged by the articulation allowed by shorter bumpstops… but that is purely speculation.

I was hoping someone has already attempted to keep the ride height control in the absence of XREAS and could comment on their solution. Worst case scenario; I’m unable to get Firestone bags to attach to the OEM compressor (this has been discussed in other threads but I haven’t found anyone who documented the successful installation)… and I’m ultimately forced to abandon the whole idea of ride height control in favour of comfortable handling.

Thank you in advance for any comments or information you guys can provide!

EDIT: Didn't realize my essay got out of control, summary below:

TL,DNR: Have rear air suspension on an '05 Limited, Removed XREAS shocks 'cuz they blew, truck handles like crap with rear bags. Can I keep the RAS or do I have to gut it for coils? Omg send halp.
 
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My X-REAS failed (back in 2010) on my 03 Limited at 138,000 km (or 85,750 miles). There was a leak in the system - in the line behind the Driver’s Side Centre Control Absorber. Leak was likely caused by corrosion of the line due to road salt used up here during our Canadian winters.

Fluid that had dripped onto the driveway was the first indicator of some sort of problem. As more fluid leaked out of the system, the suspension became worse.

I removed the entire X-REAS system (too costly to replace - but the lines are still there), and installed the standard 4Runner SR5 OEM suspension (to keep it relatively stock). This was the most cost effective repair for me at the time.

In hindsight, I might have sourced a quality aftermarket shock that was less expensive than the OEM Toyota shocks - but I did not have the luxury of having time to "shock shop" due to the nature of the X-REAS system failure.

The height control sensors crapped out in 2009 (at 132,000 km). At that time my mechanic did a temporary disable on the system, but would still allow for the on-board compressor to be manually powered up to inflate the RAS if needed.

In 2012 (at 150,000 km) the on-board compressor was showing signs of failure, so my mechanic bypassed the stock RAS system and installed an aftermarket supply line kit to work with the stock airbags.

The ride seemed pretty good with the stock SR5 shocks and RAS.
 
Thanks for the reply and info so far.

I replaced my sensors in early 2015 (I think).

Thankfully I took some fender measurements prior to installing the Billys. I will re-measure tomorrow when it's not pounding rain. Unfortunately the ride height has been adjusted, but I will remeasure to see the axle clearance and compare that to the numbers I got on Sunday... if they're the same, then it's likely there's nothing inherently wrong with what the system thinks is correct.

If someone has an original, unmolested XREAS/RAS truck, and could reach under and measure the clearance from the top of the axle to the bump stop, that would be an invaluable number for me to compare to.

I see tonnes of 4th gens around, will have to catch the owner of a Limited and ask him if I can measure his ride height, haha. If he has less clearance that I do and his ride quality is normal... well, I won't know what to think.

Adding ARK_SWAMP_RIDER to the search term RAS issued alot more interesting information than before.
 
I have factory XREAS and RAS on a 2003 v8, both systems "work", knock on wood except when I cake it up in ice and snow and have 5 big passengers.

Shoot me a pic of precisely where you'd want me to measure it, and I should be able to this weekend. (truck isn't parked where I live)
 
Keros said:
Thanks for the reply and info so far.

I replaced my sensors in early 2015 (I think).

Thankfully I took some fender measurements prior to installing the Billys. I will re-measure tomorrow when it's not pounding rain. Unfortunately the ride height has been adjusted, but I will remeasure to see the axle clearance and compare that to the numbers I got on Sunday... if they're the same, then it's likely there's nothing inherently wrong with what the system thinks is correct.

If someone has an original, unmolested XREAS/RAS truck, and could reach under and measure the clearance from the top of the axle to the bump stop, that would be an invaluable number for me to compare to.

I see tonnes of 4th gens around, will have to catch the owner of a Limited and ask him if I can measure his ride height, haha. If he has less clearance that I do and his ride quality is normal... well, I won't know what to think.

Adding ARK_SWAMP_RIDER to the search term RAS issued alot more interesting information than before.
Click to expand...


I'll measure mine after work if no one beats me to it.
 
Rodtheviking said:
From the top of the axel tube to the center, lowest spot of the bump stop, I measured it at 1 5/8 inch or 42mm.. ish.
Click to expand...

PLOT TWIST...

I'm well over 50mm right now. Thanks Rod for taking the time to help me out.

The only thing I can come up with to explain this result is that the XREAS acts as an oil accumulator when the rear shocks are compressed towards bottoming out... cushioning the contact to the bump stop such that it's not overly noticeable. I suppose it rarely comes up because most people remove their RAS with the XREAS.

I've found two companies that re-manufacture OEM bags. I will consult with them if they know the min/max length that the stock bags can be cycled to. If the minimum compressed length as-designed by Toyota is conservative (and the bags can contract further, I could install shorter bumpstops (like super bumps) and get more travel... and the super bumps would cushion the bottom-out.

Without a set of rear springs and parts to go in handy, I loathe to just install shorter bump stops and go hauling around... If I blow a bag, I'd be in a real bind to have the truck down for more than a few days.

Guess I could just jack up the truck and pull a bag out to inspect it.
 
I replaced my XREAS with conventional shocks and kept my RAS.

From the research I conducted on this site, you need Bilstein 4600s in the rear. You can go 4600s in the front but they are non adjustable like the 5100s are. I have 5100s in the front, 4600s in the rear.

I like the way the truck rides. real solid. I set the fronts at .85. No issues at all. I am glad I was able to keep the RAS as I like the self leveling feature.

If you want to lift your truck in the future, its better to convert the airbags to coils. If you want to keep RAS, you need to get stock height shocks in the rear like the 4600s.
 
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tokyoghetto said:
I replaced my XREAS with conventional shocks and kept my RAS.

From the research I conducted on this site, you need Bilstein 4600s in the rear. You can go 4600s in the front but they are non adjustable like the 5100s are. I have 5100s in the front, 4600s in the rear.

I like the way the truck rides. real solid. I set the fronts at .85. No issues at all. I am glad I was able to keep the RAS as I like the self leveling feature.

If you want to lift your truck in the future, its better to convert the airbags to coils. If you want to keep RAS, you need to get stock height shocks in the rear like the 4600s.
Click to expand...

A post in ARK_SWAMP_RIDERs threads led me to ASR's build thread, and I too have realized this.

It's very likely I'll have to bite the bullet and switch to coils.
 
tuborg_15 said:
Just wondering, what did you ended up with? Did you replace the RAS or keep it?
Click to expand...

I used the metal tech kit:
https://www.metaltech4x4.com/metal-tech-gx460-rear-coil-conversion-kit-stage-2/

And installed a set of Moog stock height coils. I think they're ~5% stiffer than stock spring rate. Seems to be a good match to the front 6112's springs.

The compressor and all the misc components are still mounted. The bags are in a shed somewhere and the sensors are in a box on a shelf.

Also, the RAS trucks have longer bumpstops than non-RAS trucks... I used Wheeler's offroad superbumps in place of the long RAS type bump stops. They're fantastic.

Now that I have the larger sway bars on, it handles corners better than the XREAS + RAS. Trying to reproduce the on-road performance of the XREAS was very difficult.
 
How much did it all cost you if you dont mind me asking? Did you install it yourself? I was planning to install OEM shocks and coilovers once Xreas fails. But still intend to keep RAS.
 
I have the RAS with Bilstein 6112s/5150s and while it is firm, I'm not sure I'm hitting bump stops. Maybe I should investigate and see if they're actually making contact.
 
tuborg_15 said:
How much did it all cost you if you dont mind me asking? Did you install it yourself? I was planning to install OEM shocks and coilovers once Xreas fails. But still intend to keep RAS.
Click to expand...

Alot more than I planned:

$230USD for the kit, shipping for that and exchange and brokerage fees (was too lazy to go down and get it myself)
$100CAD for the moog springs

All totalled up I figure it was a $500CAD job to convert. I did do the work myself for the RAS conversion. I got a bit of sticker shock when I added up all the expenses and decided I needed to save a few bucks... and it was something I could do in a weekend.


RobD said:
I have the RAS with Bilstein 6112s/5150s and while it is firm, I'm not sure I'm hitting bump stops. Maybe I should investigate and see if they're actually making contact.
Click to expand...

You'd know if you were... the rear end stops dead in its upward articulation when it runs out of uptravel for a big bump. The remaining upward energy is absorbed by the passengers' spines.

No one else I could find has reported the characteristic I found with the RAS without XREAS. Either my truck is different or my expectations are different. I would bank on the latter because the former is just a machine.
 
So how do you like your ride now? Do you think your ride is better now or it was good with the Xreas?
I want a little bit of lift too but not a lot so that the passengers sitting in the back seat suffer. If I keep RAS and adjust their height the rear suspension will become stiffer. I have not had a chance to ride in a lifted 4runner so I dont know for sure how the ride feels with a stiffer suspension.
 
tuborg_15 said:
So how do you like your ride now? Do you think your ride is better now or it was good with the Xreas?
Click to expand...

So, I guess you may be interested in the whole story then:

It rides very nicely now on-road. I would say it inspires more real confidence the driver can count on under any road conditions. The shocks and springs handle uneven roads at high speeds competently and the Addco sway bars keep the truck flat and planted under virtually any conditions. Certainly my limit of traction is in the tires, being fat all-terrain tires. The truck, delightfully, approaches the limit of adhesion and lets you know you're approaching the limit with some squealing and feedback in the steering wheel. The Addco sways put more weight into the inside tires under cornering, so I'm confident to say that it'll corner harder/faster than it did on the stock 32/24mm bars.

My ex has a 3rd gen that rides on 5100s and OME springs and many maneuvers and rough roads that are dramatic in her truck are smooth as butter in mine.

I would assume though that my off-road capability via articulation will be diminished because of the sway bars. The XREAS could move weight to the inside wheels using hydraulic force... my truck does it with the steel sway bars... thus, the XREAS would provide on-road benefit without sacrifice of offroad articulation.

It's been said that the heavier sway bars will cause a see-saw effect through bumps/holes/surface changes, however I have found the opposite when negotiating large embankments and approaches to parking lots and such. Before the Addco bars, the truck would bounce back and forth after being upset going through the approach, where the two axles have to articulate in opposite directions. Now the truck blasts through it without hesitation.

Note I drove for a year on the 6110/5160/Moog springs without the Addcos, using the stock sway bars and all new poly bushings through the entire sway control system. I had to replace the sway bar system bushings because the truck felt very tedious, nervous, and generally inspired zero confidence once the XREAS was out and 6110/5160s were in. The ancient bushings had so much slop that the sway control system wasn't even being activated. (note this is probably a testimony to effectiveness of the XREAS and sway control... never noticed it before they were gone).

I upgraded to the Addco bars because I was told by passengers that the rear seat was like riding a rollercoaster through turns. I deduced that the XREAS would provide significant sway control (making up for the tiny sway bar in the back) and removing it would certainly have the effect passengers described. Anyway, the Addcos are a vast improvement and riding in the back is normal now.

tuborg_15 said:
I want a little bit of lift too but not a lot so that the passengers sitting in the back seat suffer. If I keep RAS and adjust their height the rear suspension will become stiffer. I have not had a chance to ride in a lifted 4runner so I dont know for sure how the ride feels with a stiffer suspension.
Click to expand...

No two lift kits will be identical, and some will handle on-road better than others. It really depends on who designed the kit and what they wanted out of it. Hopefully someone designed it and didn't just slap-bang something together for valve setup and call it good.

Just keep in mind that you're replacing an engineered system: The RAS and XREAS were designed to work with each other to get a specific result. Hence why I experienced so many trials and tribulations to get back to amicable handling. Throwing any old shocks and whatever springs into the truck will make it handle... just might not handle that "great". Great is a subjective term, as well.

Confident & competent handling is +120km/hr across broken and undulating pavement in a short passing zone under wide open throttle, and thinking you could have probably gone faster but wanted to "take it easy". Negotiating speed bumps and driving over traffic control equipment aren't live and die moments... yet seem to be used often to relate how the "ride feels".

Anyway, hope that helps.
 
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Keros said:
You'd know if you were... the rear end stops dead in its upward articulation when it runs out of uptravel for a big bump. The remaining upward energy is absorbed by the passengers' spines.

No one else I could find has reported the characteristic I found with the RAS without XREAS. Either my truck is different or my expectations are different. I would bank on the latter because the former is just a machine.
Click to expand...

Oh, I know. My original XREAS had around 290k km on it before I removed it. It was shot. Speed bumps were eye wateringly painful.

I detailed some of my adventures on here. I think I called the article "My Bilstein Adventures" or something like that.
 
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