Installed Deaver 3 Leaf Aal-- Not Happy

[kylant]

I just installed the Deaver 3 leaf progressive AAL from Wheeler's. The AAL is supposed to give 1.5" of lift and be a progressive leaf unlike the normal AAL.

Well, the new leafs DID NOT give me 1.5" of lift. It gave me MAYBE AT BEST 1/2" of lift. I am so mad!! I don't what to do!!? Do I take it off, put the overload leaf back on, do I use a block, or do I put a regular AAL in?

Any thoughts, suggestions? Has anybody had similar experiences?

I really need the added lift and the increased load capacity for towing the boat!!

thanks for the help

[wylcat]

this might be a stupid question but did you remove any of the stock leaves when installing the AAL?

[kylant1]

no, the only thing i removed was the overload leaf on the very bottom. this 3 leaf pack is supposed to replace that leaf.

[wylcat]

I wonder if you would get the correct lift with that overload leaf back in place with the AAL. The AAl I used from Skyjacker was a 1.75" lift spring as well and I did get atleast that much. I have never had any experiance with that paticular set up you have...Maybe RockyMtnRay will chime in on this for you...

[kylant1]

this is from wheelers website

Deaver Racing 1.5" Lift Progressive Add A Leaf Kit: 169.00 Replaces factory overload with a 3 leaf progressive add a leaf kit. Includes U-bolts.


and this is from donohoes web site

PROGRESSIVE ADD-A-LEAF PACK:
Replaces the overload leaf with a 3-Leaf Progressive Add-A-Leaf Pack. Offers 1-1/2" of lift. Comes with Teflon Slider Pads and U-Bolts.

here is the pic

http://www.donahoeracing.com/prod_ph...p?productID=16

[TMS2U]

They replace the OL.

I put a set in a Tacoma a lill while back and got almost 2" out of it. They are the same ones for the Tun.

How did you measure? Bed unloaded?

[RockyMtnRay]

Originally Posted by wylcat

I wonder if you would get the correct lift with that overload leaf back in place with the AAL. The AAl I used from Skyjacker was a 1.75" lift spring as well and I did get atleast that much. I have never had any experiance with that paticular set up you have...Maybe RockyMtnRay will chime in on this for you...

IMO, AAL type mods in general aren't a good idea so no idea which ones give what lift. My problems with using AALs are these:

• They're a really, really crappy way to eliminate trailer-tongue-weight induced rear sag. When you hook up a heavy trailer tongue the truck's front goes up at the same time the rear goes down. AALs don't fix the unweighting of the front suspension and resulting weight transfer back to the rear suspension. The proper way to compensate for trailer induced sag is to use a weight distributing hitch which puts a third of the tongue weight on the truck's front tires, a third on the rear tires. and a third back to the trailer tires. The truck stays level and the amount of weight going on the rear suspension is usually only a quarter of the tongue weight so there's barely any rear spring compression to begin with.
• AALs (at least those that produce some lift ) change the static ride height of the rear suspension which in turn causes the brake proportioning valve (BPV) to close. A closed BPV means the front brakes are doing all the work...so you get front rotor "warping" and extremely rapid front pad wear. The good news is the BPV can be relocated downward to compensate for the change in static ride height.
• AALs also increase the rear suspension spring rate...the amount of deflection of the rear springs for a given increase in the weight on the suspension. Although the increased spring rate does keep a given amount of load from fully compressing the rear suspension (the normal goal), it has at least 3 bad side effects:
  1. The rear shock dampening rate (especially the "rebound" or shock extension dampening) is now insufficient to properly control the spring when the axle drops or the truck rises.
  2. The BPV no longer provides appropriate increases in pressure to the rear brakes as the load on the rear axle increases. This also results in excessive front brake wear and overheating. Unfortunately, relocating the BPV does nothing to fix this change in dynamic proportioning. Good luck finding a replacement BPV with a proportioning rate appropriate for the increased suspension spring rate.
  3. The decreased suspension compression from increased spring rate tends to cause people to think the truck's payload capacity has been increased....so they tend to load it heavier. Unfortunately, neither the rear axle nor the rear frame are a whole lot stronger than the rear suspension. People who have really beefed up their rear suspension in a foolish attempt to carry gross overloads have actually snapped the rear axle and/or cracked the frame. Picture of cracked frame resulting from using overload springs to carry a too-heavy load

Bottom line is that trailer tongue weights should be compensated for by a WDH. Increasing the spring rate and/or lifting the rear has really bad effects on the truck's front-rear brake balance. Stiffening the rear suspension should not be considered a way to improve the truck's load capacity.

[kylant1]

i stopped by Wheeler's Offroad today and talked to them about my issue. They said I was the second or third guy with a D-cab with this problem. They said they were going to let Deaver know. It must be something with the D-cab; weight maybe

We brainstormed a solution and came up with a 1" block or just adding the overload spring back to the bottom of the spring pack. I am going to try both and see which one is better.

They guys there were super awesome and gave me a smokin' deal on the new block, new center pins, and a Donahoe spanner wrench. Awesome customer service. Good people

I will post results tomorrow

[TMS2U]

Good to hear-

Gary has always done me right!!!!

[clongjax]

Originally Posted by RockyMtnRay

IMO, AAL type mods in general aren't a good idea so no idea which ones give what lift. My problems with using AALs are these:

• They're a really, really crappy way to eliminate trailer-tongue-weight induced rear sag. When you hook up a heavy trailer tongue the truck's front goes up at the same time the rear goes down. AALs don't fix the unweighting of the front suspension and resulting weight transfer back to the rear suspension. The proper way to compensate for trailer induced sag is to use a weight distributing hitch which puts a third of the tongue weight on the truck's front tires, a third on the rear tires. and a third back to the trailer tires. The truck stays level and the amount of weight going on the rear suspension is usually only a quarter of the tongue weight so there's barely any rear spring compression to begin with.
• AALs (at least those that produce some lift ) change the static ride height of the rear suspension which in turn causes the brake proportioning valve (BPV) to close. A closed BPV means the front brakes are doing all the work...so you get front rotor "warping" and extremely rapid front pad wear. The good news is the BPV can be relocated downward to compensate for the change in static ride height.
• AALs also increase the rear suspension spring rate...the amount of deflection of the rear springs for a given increase in the weight on the suspension. Although the increased spring rate does keep a given amount of load from fully compressing the rear suspension (the normal goal), it has at least 3 bad side effects:
  1. The rear shock dampening rate (especially the "rebound" or shock extension dampening) is now insufficient to properly control the spring when the axle drops or the truck rises.
  2. The BPV no longer provides appropriate increases in pressure to the rear brakes as the load on the rear axle increases. This also results in excessive front brake wear and overheating. Unfortunately, relocating the BPV does nothing to fix this change in dynamic proportioning. Good luck finding a replacement BPV with a proportioning rate appropriate for the increased suspension spring rate.
  3. The decreased suspension compression from increased spring rate tends to cause people to think the truck's payload capacity has been increased....so they tend to load it heavier. Unfortunately, neither the rear axle nor the rear frame are a whole lot stronger than the rear suspension. People who have really beefed up their rear suspension in a foolish attempt to carry gross overloads have actually snapped the rear axle and/or cracked the frame. Picture of cracked frame resulting from using overload springs to carry a too-heavy load

Bottom line is that trailer tongue weights should be compensated for by a WDH. Increasing the spring rate and/or lifting the rear has really bad effects on the truck's front-rear brake balance. Stiffening the rear suspension should not be considered a way to improve the truck's load capacity.

Ray, you make some pretty convincing arguments to not use a beefed up spring system in the rear. I was particularly interested in how it messed up the braking ratio between front and rear. Is it safe to say that raising the front end, say by 2 inches with a new coilover shock going to have the same effect?

[RockyMtnRay]

Originally Posted by clongjax

Ray, you make some pretty convincing arguments to not use a beefed up spring system in the rear. I was particularly interested in how it messed up the braking ratio between front and rear. Is it safe to say that raising the front end, say by 2 inches with a new coilover shock going to have the same effect?

If...really big IF...you don't do anything to the rear when you raise the front end, then no, no problem with the BPV. That's not to say you won't have some problems...the greater angle on the front half shafts causing CV joint problems being one. But as long as the rear stays the same, then no problem with front/rear brake proportioning.

However, raising the front by two inches is likely to make the truck look pretty nose high, especially if you have any load in the bed (the reason the stock truck comes nose low from the factory is so it looks level when you have some load in the bed). And so you're likely to want to raise the back, maybe only by an inch or so. And that's when the troubles will start if you do it by increasing the rear spring rate (like with AALs)...then you get into exactly the issues I discussed earlier...incorrect shock rates and bad BPV performance. But if you do it with spacers, you may be OK as long as you also relocate the BPV by exactly the same height difference.

Suspension mods are far trickier than they look to be with this truck...Toyota put a lot of engineering into choosing/optimizing the factory ride height and any changes to that ride height need to be very carefully thought through. I've made dozens of mods to my truck but one area that I won't change is the suspension.

[clongjax]

Thanks Ray, your insight is always appreciated.

[H2O_MAN]

Originally Posted by RockyMtnRay

I've made dozens of mods to my truck but one area that I won't change is the suspension.

I did make many changes to the suspension on my T100 (T-barz, Air-Lift, Alcan's), but after reading what RockyMtnRay has to say about the Tundra I decided not to change my suspension with the exception of TRD 4WD coils in the front and the possible addition of Ride-Rite bags in the rear if I get back into the bottled water business.

Hey RMR, when you have the time - could you post pictures of your mods, trailer, etc...?

Thanks for all of the solid advice ~

[RockyMtnRay]

Originally Posted by H2O_MAN

Hey RMR, when you have the time - could you post pictures of your mods, trailer, etc...?

Gladly...when time is available and the weather is decently comfortable (it's winter here in Colorado and I'm totally buried with work). Kinda doubt that both time and suitable weather will be available until at least April or May so please don't hold your breath.

Thanks for all of the solid advice ~

Welcome.

[ride4life]

Ray is the BPV still used with ABS? Or did this become a non-issue when ABS became standard (2004?)