Did i install the wrong Bilstein shocks on my GX470? (1 Viewer)

[danmm7]

Few weeks ago i bought and installed a new set of rear shocks for my '05 GX470.

I bought the Bilstein 5100 - 33-187174 - 2" Lift Rear Shock for Toyota from Amazon.

This is the part number that was mentioned on the forums a few times and it is also the part number that is supposed to fit the FJ Cruiser and the 4 Runner.


Why am i having doubts now?

1. My GX470 is 100% stock. It is not lifted at all. It uses the original OEM air bags (they work well).
2. In the description, these shocks say that they are for a 2" lift. Again, my car is NOT lifted.
3. During the install, i realized that i need to compress the Bilstein shocks fully to the max in order to barely fit them on my car. They were so compressed when i finally put them in, i was wondering how are they supposed to absorb any impacts from the road ?!?!
4. The ride seemed fine when i first drove the car. Not too bouncy, not too harsh, not too soft. Felt well controlled. I drove the car yesterday and today and i noticed that the rear seems to bottom out more often when going over speed bumps. Maybe it is all in my head, but this seems to be a new development since i installed the bilstein 5100s. Did they get damaged? Or are they the wrong model/part# for my car?
5. Everyone was giving great positive reviews for the 5100s as far as ride quality and handling .... and i don't think my experience so far matches that. I wonder why?

I guess my main question is.... can i really install shocks that say "2 inch lift" on a non-lifted truck?

If the answer to the above question is "no", then what is the correct Bilstein rear shock (part#?) for a stock GX470?


Thank you for any feedback!

 

[Brake Weight]

Here’s the 5125 that I mounted June 2017. Remember that these airbags have ride height adjustment. Our GX, to me, always felt like it was bottoming out when it was stock. I just didn’t like it. So it got a mild lift and new suspension.


You didn’t compare them before installing?

 

[kbahus]

Product Search Detail - BILSTEIN

They are spec'd for 0.5" to 2" lift, but without flexing the truck and measuring your compressed and extended lengths there is no 100% way to tell. If you really wanted you could disconnect one, compress it all of the way and mark that point on the shaft, put a small zip tie on the shaft, drive it around, and see if the zip ties has moved to the point the travel runs out. This shock is the only option Bilstein offers in the 5100 series for the 120 series. You could go to a 4600 Series, those were designed for a stock vehicle. Here is the 4600 part number: Product Search Detail - BILSTEIN

Here is my guess: if you feel them bottom out they are too long. I run the same shocks with a low lift (895E springs) and I have never felt them bottom out.

 

[Jstawgn]

Check your bump stop. The OEM air spring bunp stop are known to crack and lost part of it causing a lot less progressive damping.

The shock should be fine since it was never required to use extended bump stop as long as the original bump stop is still in good condition.

You could adjust your rear ride height a little bit by adjusting the ride height sensor attached to the rear axle upper control link.

 

[Kelevra]

What coils are you using in the rear?

 

[GXer04]

I ran those at stock height for a month without issue before raising the rear.

Jstawgn has a good point to check your bump stops. If they are okay, I'd cover the bump stops in chalk and drive it to see if it's impacting the axle.

Lastly, double check your part numbers and the pics above. The trouble you decribed installing them sounds like the wrong shock possibly.

 

[fastlane1000]

He's got the right part number. I just ordered those for my GX. I just haven't installed them yet. I bet he's bottoming out on the stock bump stops and needs to adjust his ride height sensors. Once those bump stops get old they harden and make a more noticeable impact when they hit. If you don't want to raise the rear a little via the ride height adjustment then cut the bottom of the bump stops off.

 

[danmm7]

So it sounds like i ordered the right parts. This is the good part.

The bad part is, clearly my ride is not that great, mostly over bumps. The bump stops, at least visually, look great, BUT, on a 2005 truck with 140k miles, rubber must be really hard. I can replace the bump stops but i am pretty sure this will not fit the bottoming out over speed bumps.

Here are some questions:

1. Since my front height is stock, if i adjust the rear height sensor to raise the truck on the back.... will that cause the truck to be uneven?

2. If i cut the bump stops a little (not sure how much exactly).... will that affect anything else negatively?

3. Since these Bilstein 5100s introduced all these complications on my stock truck.... i am starting to wonder if they are really worth it?!? Perhaps i should go back to something simple like KYB shocks or OEM 4Runner shocks and sell the 5100 for a few bucks.

 

[Jstawgn]

Are you still running stock front shock? Unmatched shock would change the suspension frequency between front and rear.

What you are feeling is the weak rebound front shock tranfering too much weight to the resr. The bilstein is much more progressive speed sentive valving trying to dampen the compression and you feel like it's hitting the bump stop.

In this case you need to update the front or get much softer rear shock.

 

[kbahus]

3. Since these Bilstein 5100s introduced all these complications on my stock truck.... i am starting to wonder if they are really worth it?!? Perhaps i should go back to something simple like KYB shocks or OEM 4Runner shocks and sell the 5100 for a few bucks.

If you are staying stock, may as well find some low mileage used OEM shocks so you can at least retain the all of the factory functions.

 

[kbahus]

Are you still running stock front shock? Unmatched shock would change the suspension frequency between front and rear.

What you are feeling is the weak rebound front shock tranfering too much weight to the resr. The bilstein is much more progressive speed sentive valving trying to dampen the compression and you feel like it's hitting the bump stop.

In this case you need to update the front or get much softer rear shock.

He has to lift the truck if he wants the 5100’s to work. If he wants a factory ride height, 5100’s are not the proper shock. It is not about if the firmness of the damper.

 

[danmm7]

To add some more detail ... yesterday i replaced the stock front OEM struts/coil assemblies with KYB Ready Strut Assemblies (strut+coil combo).
This definitely improved the ride on the front. A lot less body dive/squat now and the truck rides smoother over bumpy roads. I like it.

Sadly, the rear bottoming out over speed bumps did not chance one bit. I think i am going to put the slightly used rear KYB shocks back and just sell the 5100s.

*****
Here is a new one...

Since now i am spending a bit more time with the truck and i am observing the suspension a lot more (usually my wife drives it all the time), i noticed something else that is kind of disturbing.

If the truck sits parked for an hour or more, the rear sags, especially on one side (Passenger). As soon as i start it, the compressor comes on and in a few seconds the suspension is back to normal. Looks like the air bags (or one of them) are slowly leaking. They have about 145k miles on them...13 yrs old.
Luckily, i have a set of brand new OEM airbags sitting in boxes. I got them cheap a year ago, just in case.
From the limited research i did, it appears that the airbags swap should be pretty easy, DIY procedure.
Am i underestimating this?
Any other more likely causes for the sagging when parked, aside from the airbags?
Any tips/trips for the swap?

Thanks!!

 

[Brake Weight]

So no measurements of either stock nor 5100 prior to install?

If you set your rear ride height to the highest setting, does it still bottom out? Just for giggles. Set the ride height at the lowest and let it settle out. Flip the switch to the highest and watch it air up. Does it move equally on both sides?

Here’s what I came up with before the rear coil swap. The shock measurements are with it still mounted so that I could gauge what to get with a lift.

Aired up rear bags
21.25"-shocks
23"-hub to fender

Collapsed rear bags
19.5"-shocks
21"-hub to fender

 

[runningdrew]

To add some more detail ... yesterday i replaced the stock front OEM struts/coil assemblies with KYB Ready Strut Assemblies (strut+coil combo).
This definitely improved the ride on the front. A lot less body dive/squat now and the truck rides smoother over bumpy roads. I like it.

Sadly, the rear bottoming out over speed bumps did not chance one bit. I think i am going to put the slightly used rear KYB shocks back and just sell the 5100s.

*****
Here is a new one...

Since now i am spending a bit more time with the truck and i am observing the suspension a lot more (usually my wife drives it all the time), i noticed something else that is kind of disturbing.

If the truck sits parked for an hour or more, the rear sags, especially on one side (Passenger). As soon as i start it, the compressor comes on and in a few seconds the suspension is back to normal. Looks like the air bags (or one of them) are slowly leaking. They have about 145k miles on them...13 yrs old.
Luckily, i have a set of brand new OEM airbags sitting in boxes. I got them cheap a year ago, just in case.
From the limited research i did, it appears that the airbags swap should be pretty easy, DIY procedure.
Am i underestimating this?
Any other more likely causes for the sagging when parked, aside from the airbags?
Any tips/trips for the swap?

Thanks!!

Yes, sounds like you have an air spring/bag that is going out. My air compressor was working overtime - I was hearing a loud hiss of air being released form the leaking bag each time I turned the truck off, and it would ride very rough. I swapped out air bags this Saturday, all is good now.